4l80e max line pressure. The converter is a triple disc lock up 9.
4l80e max line pressure It looks like the converter is fed from the TCC solenoid which is using line pressure. TFMPRS is what the PCS is commanded to produce (see the yellow hydraulic The tech. Jump to page: Similar Threads. You've got room at the lower throttle/load areas to increase what line pressure column you're calling if you want tighter part throttle shifts, but you said I have a 4L80E that has a manual valve body with trans brake. B. You might experience erratic shifting or excessive wear in certain parts. Chris, line pressure controls indexed to engine vaccuum are very accurate providing the engine uses a carbuerator,providing no supercharger or turbocharger is presentto produces positive pressure in the intake manifold which would result in a high vaccuum signal and low line pressure under maximum load. Played around with the torque management on the 4l65e a bit more and got it working pretty well. Rebuild a 4L80E Transmission with the TransGo HD2 Kit. That is located just above the shift lever on the transmission. 709 posts · Joined 2011 Add to quote; Only show this user #1 · Aug 6, 2015. Figure 4 shows the position of the pressure regulator valve with stock programming when desired and actual pressure is between 60 psi to 70 psi and line pressure duty solenoid percent near 22 to 24. does anyone know how high you can set the trans line pressure of the voltage for a 4L80E without burning up the solinoid. Shifts fine automatically or manually, and "locks up" in 3rd, but if shifter is placed in OD (4th gear), the car actually seems to "neutral out" unless transmission temperature is hot. pressure instread of tps vs. Also if you unhook the force motor it will go to max line pressure as the force motor raises line pressure with less If the actual line pressure reading is more than 172. Also change the Max Pressure to 96, as it usually is 90 stock. throttle angle/transmission torque demand. Line Pressure Booster Kit 4L80E; 6L80, 6L90; Dodge-Cummins Diesel; Powerglide; Line pressure booster kit 4L60E-LB1 fits early-style GM 4L60-E, 4L65-E and 4L70-E pumps. and the maximum output torque is 885 ft. This is not electronically controlled. I have Tunercat and a cable, have been looking at my pressure tables in the PCM. My transbrake is a Jake's D1, which requires the car to be in low. Is this line pressure high enough to keep the clutches from slipping with the high torque at low rpm of the 4BT or will I need to increase the line pressure when I set up my controller? In "drive" with no load on the trans 600 rpm 80 psi Sonnax Performance Pack HP-4L80E-01 upgrades GM 4L80-E and 4L85-E transmissions for maximum performance and durability in work/sport vehicles. jpg. no matter what throttle %,But when the torque convertor locks the line pressure goes The line pressure is about 220psi. The 4L80E also uses a reverse boost valve like the 4L60E does which roughly doubles the line pressure in reverse to increase the holding power since so many clutches are activated to get reverse. P0869 – High Line Pressure The transmission I just bought came shipped with a tag that reads a line pressure test of 235 PSI in every gear @ 2,000 PSI. 093” hole from the line pressure to converter charge circuit in the pump as shown. 4 kPa (25 psi) higher than the desired line pressure, but is less than the highest line pressure ever used in the current gear, P0933 sets. 0 KB, 17 views) 1985 C10 SWB, LM7, 4L80E. Remove the 60 second time delay for PE, set it to 0. and I noticed that other TH400's from the same place that are only rated for 650 HP max and less, all have a line pressure of 180-200 PSI. Low Line Pressure in 4L80-E in Diesel-Powered Trucks TASC Force Tips Author: Gregg Nader, Sonnax. Danny Cabral Our pressure regulator springs are approximately 10% stronger than OE and more conservative in impact than other aftermarket kit springs. Ive seen some tunes where the pressures are maxed out and they eat transmissions like they are candy. Many aftermarket “kit” springs are a compromise, raising pressure too much at idle and not enough at maximum pressures. I have power to all 3 pins for the pressure switch, at the connector with the ignition on as well. Speaking of line pressure Looking at a stock tune of my 2011 Corvette LS3 with 6L80E transmission -vs- a modified tune that was done to the car later on the only difference that I can find while looking at just the transmission data is that the 'Max Line Pressure' was increased from 726 kPa -to- 841 kPa this slight change made the part throttle and full This takes the electrical out of the equation and sends it to max line pressure. However this is an almost foolproof system that many builders have adapted in electronic controlled systems to prevent tuning caused failures. 0/4l80E With stuff from. Like I said my line pressure is still 160 ish in park according to Holley gauge and laptop. The converter pressure during a 3rd gear pull unlocked would drop to about 35psi and the level off to 50 psi. 4L80E STREET STRIP PRESSURE REGULATOR SPRING 4L80CC/SSPRS The installation of The max line pressure can cause problems if the transmission isn’t modified for it. Originally Posted by Jetn3. 73's. For example- stock spring will give you 190-200 with plug. I keep it nice and soft off boost (around 40 Your pressure tables appear to be pretty agressive at full throttle - you're calling 96% (which is max) line pressure for any shift at over 460 ft-lb and 93% for all shifts over 340 ft-lb. the advent of the tv cable and its regulation of The installation of this upgraded pressure regulator spring will raise maximum line pressure to approximately 195 psi. 9 but not at the expense of braking the transmission so i just want to make sure im set safely for the power its pushing when on the bottle (524 whp 555 Line Pressure with Transbrake- Jakes D1 4L80E 09-08-2014, 12:18 AM. If your MAF is disconnected, these will cause it to max the transmission line pressure. This device is a set of five, nor-mally open, pressure switches that detect fluid pressure within the valve body passages (Fig-ure 11). should be fairly steady when testing the max/1500rpm range, the What kinda line pressure should i see on the cooler circuit of a built 4L80 with a 3600 stall? I am measuring on the pressure side, off the front fitting of the trans (late model trans with front and rear fittings). If you are running fixed line pressure (with epc plug), you need less spring for desired pressure because the epc isn't bleeding off. It may say line pressure but it's actually duty cycle which effects your actual line pressure. bgblockelcamino Discussion starter. Many parts listed here also fit 4L85-E and/or TH400 units. png (373. I want to increase my shift firmness slightly. been chasing an issue with 4l80. HOT ROD Staff Writer Sep 19, 2013. The 4L80E was installed in a lot of different GM trucks and vans, so they are plentiful and easily found at a junkyard. 2@123 mph, since im so close i would like to get a 10. 50: 4L80-3FM: Full manual forward pattern: $6,231. yup i tried this. The You will need an external pressure gauge (or logger) on the 4L80E/4L60E line tap to see the actual line pressure. With fixed line the pressure may not reach the 4L80E; 6L80, 6L90; Dodge-Cummins Diesel; Stronger pressure regulator springs raise pressure equal amounts at idle and maximum pressure. the leak may be overcome with "max" line pressure. You just need to Pin Map this Input. I know when tuning my 4l80e w/ 411 Gen3 , The torque management The MPS lets the transmission know what gear that it is in. Having looked at other Terminator X files in the wild, they're pretty much the same. The trans has 5,000 street miles and about 20 track passes. For a more in-depth look at raising line pressure, read The Prescription for So i can turn up the max Line Pressure table up to 93, adjust the upshift tables (how much I dont know), & also adjust the FMC positive & negative tables (again I dot know how much) Using a pressure gauge is the safest way to tune a 4l60/4l80. rtuhro. 03-13-2022 #6. In the Shift Pressure section there are: Max Pressure Max Pressure B Max Clutch Max Line Pressure Table Base Shift Pressure Tables One other change that I typically do is to go to the Trans Diag Tab and Disable the Max Line pressure DTC's for P0101, P0102 and P0103. HPTunersShiftPressure. I ran an 80e for several years with deleted line pressure solenoid and had no problems with it at all. 3 with a GT2-3 cam and 2000 LS1B w/ COS 5. Values above 60% typically result in a line pressure too low for any throttle position. Pressure gauge is hooked to the line pressure port of the trans. pressure. I haven't seen a max line pressure DTC enabled since 2001. If you get a p1810 code, it commands max line pressure for your trans. Top. 2014 GMC Sierra Z71 5. Regulating point A is the connection to exhaust, which is connected back Line Pressure %, 4L80E 05-20-2021, 10:10 AM. Unplugged, the line pressure in the transmission will go to an uncontrolled max value that can mask a leaking concern inside the unit. David Jackson. The regulating feature appears to be the line pressure during lockup as opposed to a About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright when do i want to increase max line pressure? what is the difference between 'max pressure' and 'Max pressure B'? I did a nitrous pass on the camaro, it went 11. 2 posts · Joined 2009 Add to quote; Only show this user #1 · May 13, 2009 (Edited All, I've been digging for a solution on this, and it appears that some have issues w/ P59 and some don't. manufacture and distribution of I think these tables could play a role in why I don't see max line pressure after lockup. If you monitor the log, you can see TCC pressure rise as TPS increases. I installed a TCI reverse manual valve body kit which modifies the boost valve and regulator to lock the pump at line pressure. TFMPRS is what Below is from a 4L80E service manual: With engine running, shift transmission into Drive with foot on the brake, at idle in Drive, Park & Neutral, the main pressure should be To start, this is a turbo (S366) third gen 5. The computer controls the relationship between transmission line pressure and engine power, and it knows exactly what the amperage of the transmission pressure-control solenoid (PCS) should be at any given throttle position and engine speed. www. Like earlier automatics, the 4L80 features one line pressure tap available for testing and diagnostic Diagnosing a 4L80-E shift concern can be easy, as long as you understand some basic techniques to help get to the root of the problem. com Page 1 PERFORMANCE Pump Parts • Line Pressure Booster Kit • Lube Regulated Pressure Regulator Valve Valve Body Parts • TCC Pressure Limiter, Valve, Spring & Plug max line pressure and lubrication. 1-2 shift quality and reverse may be okay when cold, then slowly deteriorate into a long shift or slide bump as the temperature increases. Cars running great. When cold the transmission will go in reverse and forward, after it warms Right, going to make a statement about stock 6L80 / 6L90 Raising the max pressure, max pressure B, max clutch & max line pressure tables does nothing on a stock unit to increase line pressure. You don't want that to happen. 98 amp, since its resistance is about 5 ohms it is tempting to use ohms law to conclude you can apply 4. (moving towards 0%) increases line pressure with 0% providing maximum line pressure applied. Line pressure then goes into a valve in the valve body called the AFL (Actuator feed limit) which regulates how much line pressure goes to the clutches/bands servos. This prevents the converter from suffering charge loss during max line pressure situations. Heavy Duty Forward Clutch Hub 34322-01; Heavy Duty Clutch Retaining Ring 28124 Put it into my street rod which already had a 4L80 and a first gen compushift controller. com Racing GM Automatics 4L80Experts. Page 1 of 5 1 2 3 Last. The pressure should rise with throttle. The Pr. In the ECM Constants table, it has Max Line Pressure set at 90psi. The current specification is 0. The turbo 4L80E guys go with 0. We just made it neater. 3LS10 Experienced MS/Extra'er Posts: 365 Joined: Tue Sep 24, 2013 8:31 pm. By rcapone March 19 By adjusting the line pressure, the PCM can maintain acceptable transmission shift times. Automotive Repair Shop. off valve to maintain a desired pressure. Reverse will act in the same manner, 4L80E Intermediate Clutch Failure, 1-2 Slide Bump, Slips in Reverse (continued) 2nd gear: When pressure is at maximum at idle, cooler flow drops further to . At maximum pressure, you’ll get incredibly hard shifts. 3 GPM. Oddly enough, i checked line pressure with the trans connector unplugged and i got about the same readings as when it was plugged in (maybe 5psi higher, tops). barthautala. This consisted of: - New clutches and generic rebuild kit - Billet input shaft and forward hub - New pump with Sonnax boost valve and PR valve - Transgo HD2 I have some general questions about the Shift Pressure section of the 6L80E Transmission tune. Toyota Sequoia And in the case of a turbo 400 you have modulator line pressure that goes to this hole and that's coming off the the modulator valve after in the modular valve reduces it to depending on the vacuum source The set time is a bit slow on this video because we forgot to max out the line pressure with the pressure control solenoid. Reverse always has a higher line pressure. -2000 S10 5. Temporarily assemble Allows regulated flow to the converter charge/lube circuit at vehicle idle. The converter is a triple disc lock up 9. November 17th, 2010. One of my Trans cooler lines on my 01' GMC 2500 (with 4L80E) tow rig rusted through at a clip and produced a pin hole. or N, and 67-324 in R. 8, S480 Turbo, MS3x. Can I just cut out the small section of rusty hard line and use a small section of hose with maybe a double clamp at each end. TH400/4L80 Band Adjustment. The only way to increase line pressure is raise the reported torque via the torque model or install a Sonnax line pressure boost valve kit. Operation: Max Line Pressure. The 4L80E uses an electronic control module to monitor a number of vehicle and engine inputs as well as In other words 100% PWM TCC for 80PSI vs 150PSI of line pressure is two completely different converter pressures despite both having 100% PWM TCC signal. sonnax. I've altered settings in the trans elsewhere with no softening of the shifts. 4L80E line pressure. To check rear servo clearance disassemble the servo as shown. After a year of fiddling around with my car, I've finally started driving it a bit and datalogging. TAP cell 4 is the lowest adaptable torque range and TAP cell 14 is the highest adaptable torque range. 5TD 2500 4x4 4L80 3. The 4L80E is notorious for getting Search titles only By: Search Advanced search 2003 GMC Sonoma LQ4 6. I have a pressure gauge on the trans cooler line. Joel Johnson 1969 Nova LS 408 Dominator EFI Jakes Performance Stage 3 4L80e Moser Wavetrac 12 bolt. 06-18-2018 #3. There is insufficient oil volume to work the balance side of the pressure regulator valve to open the converter charge circuit. With engine running shift transmission into drive with foot on the brake, at idle in drive, park and neutral the main pressure should be approximately 40-70 psi and with throttle depressed to In other words 100% PWM TCC for 80PSI vs 150PSI of line pressure is two completely different converter pressures despite both having 100% PWM TCC signal. Truck Repair. 3LS10 Experienced MS As the title says, I have a fixed line pressure 4l80e that makes good pressure when cold, but slowly drops as it heats up. It is a force motor that responds to current. Jump to Latest 14K views 3 replies 3 participants last post by Crosley May 14, 2009. 00 command shift times. The valve body separator plate and accumulator mods have a large part in the shift feel of the unit and At max line the normal pressure in the cooler, not the converter is usually 80 psi. By pullincrazy88 in forum 4speed RWD/FWD Transmission Tuning (incl T42) Replies: 2 Last Post: November 17th, 2010, 12:56 PM. The 2-minutes is so the Trans doesn't overheat & cause clutch damage especially with new clutches. By dezzi in forum Allison 5 & 6 Speed Don't just block the TCC regulator valve in place at full open, because this will put max line pressure into the torque converter, ballooning it during WOT and possibly damaging the crankshaft thrust bearing in the process. Doctor Steve's Transmission Clinic walked us through the rebuild of this electronic gear changer. Volvo 940, 2jzge, MS3Pro, daily 240Z, 2JZ, MS3Pro boost control. Fits 4L80-E, 4L85-E. All of which I am experiencing. I got it back in the truck and when starting for the first time I put a 0-300 psi gauge on it to verify line pressure. A voltage source in not a good way to control this electronic pressure control. | video recording Uh we have a 4L80E 3 r d Gear “D3” Transbrake We recommend drilling a . Always replace the 3rd/Reverse 4L80E behind a 2001 5. In my case, the transmission is maxing line pressure due to the P0102/0103 codes. Lower the 5,500 RPM down to 2,000. Ensuring that 30/35 psi is not max line pressure, but is somewhat high for idle (expected is 5-10 psi). As you see in the diagram below, the pid GM. 73's reg cab, The Feed Wagon, Max-E-Tork, Flowmaster DP, straight piped, manual GP overide, posi-lock actuator, 3" body lift, flat bed, trip hopper feeder, The transmission goes into protective mode to protect itself MAX LINE PRESSURE AUTOMATICALLY AS A SAFEGUARD AND STAYS IN 2ND. Was wondering on a 4l80e, when the converter is locked and the line pressure is at max, what charge pressure is the converter seeing? Trying to understand the fluid schematic. 50: 4L80-3RMTB: Reverse manual Transbrake: $5,505. line pressure. Heavy Duty Truck Basic Build; High Performance Build (Under 1,000HP) Line Pressure Booster Kit 4L80E-LB1* Internal. 50: 4L80-3ATB1: Automatic shift with Manual Low Transbrake (transbrake can only be activated in manual low position) $5,626. Body Check. 0 seconds. Shifts feel like stock but pull 15 to 30 degrees of timing, Check out these handy Sonnax build guides to get maximum results out of your rebuild. I’m getting a solid 200psi in every forward gear, park, neutral, and with trans brake applied. The Line Pressure transducer harness connector is simply plug & play into the optional Holley EFI 554-136 500 PSI Pressure Transducer. You will need an external pressure gauge (or logger) on the 4L80E/4L60E line tap to see the actual line pressure. 73's reg cab, The Feed Wagon, Max-E-Tork, Flowmaster DP, straight piped, manual GP overide, posi-lock actuator, 3" body lift, flat bed, trip hopper feeder, The editor should clamp the max pressure to 96 psi. Reverse is about 105psi. Holley has them ramp to 100% duty cycle very early on when 4L80e Pressure drop during 1-2 shift only 4L80e Pressure drop during 1-2 shift only. Jump to Latest 7. My cooler pressures were as high as 130 when the converter was in lock up. 3L, LJMS turbo cam, 4L80e, 8. 55 Chevy. hot. Required. The pwm solenoid will automatically max out line pressure (hydraulic pressure) 1994 6. View Profile So I should be running the correct 4l80e segments. M. I have a 3. I know this works with smaller vehicles but I When the engine attached to a 4L80E is idling in drive, between 500 to 1000 rpms, the pump output or volume is VERY LOW. The question I have in Line pressures at start up were 150 psi in all forward gears and 275 ~ 300 in reverse. Lower the HOT/COLD pedal enable from 90% down to 70%. jakesperformance. who built my 4L80E recorded the following line pressures when testing the transmission in shop. For a year and a half, the pressure would be around 35-40 psi at idle and driving around. Its in a heavy 4x4 with a fresh SRTA 4L80E 2K stall and 3. When Troubleshooting the 4L80E Automatic Transmission Page 9 Transmission Range (TR) Pressure Switch Assembly. It is normal for TAP cell values to It’s easy to upgrade GM 4L80-E and 4L85-E work/sport vehicles for maximum performance and durability with this new comprehensive kit from #Sonnax Uh we have a line to lube pressure 4L80-E, 4L85-E Line Pressure Booster Kit Sonnax hydraulic line pressure booster kits contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases as driving conditions become more demanding. Comment. " Last edited by DRIVER456; 06-07-2022, 04:33 PM. i can get a 4l80e for $800, shift kit for $100, make a controler for probably $300 or so. Last edited by barthautala; 06-25-2018 at 01:31 PM. 9 volts to it and get the maximum current; however this is not a good solution, the variation of the force Operation: Max Line Pressure. This raises line pressure 35-40 psi over stock, resulting in firmer shifts and increased transmission torque capacity at all throttle angles. Motor Mechanics. The newer trucks don't have that table, and I just did a SD tune on a 2007 6L truck with the Gen III pcm and no shift pressure issues. Large ratio boost valves provide higher pressure incrementally and when it is needed the most. 5. The thing that is unique about the trans, when compared to the TH400, which can have extremely high converter charge pressures when high line pressures are in use, is The Ford 4R70W transmissions already have the "Line Pressure Signal" wired to J4-B21. 100 PSI of converter charge pressure generates 89 pounds of rearward thrust on the GM 4L80-E, 4L85-E PERFORMANCE PACK 800-843-2600 • 802-463-9722 • F: 802-463-4059 • www. Line pressures at start up were 150 psi in all forward gears and 275 ~ 300 in reverse. Lower The 4L80E is a prime example of an advanced, electronically controlled transmission. For a 4L80E with the transbrake you 2000 TransAm, 4L80E transmission with Rossler D3 transbrake. I just rebuilt this 4l80e the other day and got it installed. The case is die cast aluminum. 4K views 19 replies 6 participants last post by jakeshoe May 26, 2020. Part # 34200-14K 4L80-E, 4L85-E Line Pressure Booster Kit 4L80E-LB1. After a couple minutes of running the pressure in forward gears No power results in 2nd gear only, max line pressure and no TCC PWM. might need to have my converter reworked to work but the circle D guys are cool and would Maximum engine input torque for the 4L80 is 440 ft. transmission line pressure 4l80. With the exception of the line pressure. 4L80-3A: Auto Shift for computer controlled applications: $5,263. Post Cancel. 50: 4L80-3FMTB1: Full manual forward pattern with Manual It’s easy to upgrade GM 4L80-E and 4L85-E work/sport vehicles for maximum performance and durability with this new comprehensive kit from #Sonnax. 4l80e. The combination of these springs and valves in a Sonnax kit gives you the best of both worlds: a modest pressure increase at the When dealing with 4L80E transmission problems, knowing the common issues and their fixes can save you time and money. Innovative components work together to precisely recalibrate pressures and shift accumulation, delivering firmer shifts under load without sacrificing low-speed drivability. It also looks like the converter limit valve isn't doing anything at this point. I'm not sure what happened here as I'm using an GCF 4L80E from Holley's pre-configured base calibration. . Because converter charge pressure is a derivative of Line Pressure, converter charge pressure will vary with operating conditions, ie. My car took out a thrust bearing last year and on tear down i The 4L80E can be a complicated transmission. There is nowhere in the trans diag page to disable the Maf fail - max line pressure setup. Information regarding fixes and mods for this are currently being added to our 4L80E Raising the max pressure, max pressure B, max clutch & max line pressure tables does nothing on a stock unit to increase line pressure. I also realize that playing with the line pressure can cause the TCC to refuse to lockup under certain conditions. Post I have a 4wd 80e with a d3 transbrake built at a local shop rated to 1500hp for a truck I’m building. If there was a way to monitor exact internal pressure it very well may be what GM Powertrain spec is. Attached Images. After a couple minutes of running the pressure in forward gears slowly dropped to as Line pressure is best done with a pressure gage installed to the pressure tap. 5" I believe its around a 3800 stall. and even more line pressure to live. 8 Buick engine that ate 2 sets of thrust bearings. On the older vehicles with the max pressure DTC enabled, in SD mode with stock shift pressures, the trans shifts are very hard. I can say now I think I have a pretty good grasp of 4L80E hydraulics and the Hydramatic engineers did some pretty neat stuff there. This is after about 20 minutes of driving, the tran 4L80E main line pressure adjustment. I was struggling with my 4l80 shifti Trans worked fine when I tuned it with EFILive,Installed terminator x max with trans control,My line pressure will not rise leaning on the throttle,1,2,3 and 4th gear it stays at 97psi. 60-65 forward and 90-100 Reverse, even unplugged, even at full throttle while driving. Do you use the same procedure when tuning 4l60e's with shift kits and can it be used on 4l80e's as well? 1999 corvette FRC - LS2, Tick tq max stage 3 cam, AI 232cc 243's, FAST 102 intake, NW 102 TB, 1 7/8 headers, X pipe, Borla When hot, max line pressure may test low in reverse when the piston is cracked. mert4787 Discussion starter. 3 N/A Mod'd stock intake Right, going to make a statement about stock 6L80 / 6L90 Raising the max pressure, max pressure B, max clutch & max line pressure tables does nothing on a stock unit to increase line pressure. 06 to 0. manufacture and distribution of the highest quality products to the In the 4l80 repair manual, it reads that an illegal combination of grounded pins at the pressure switch will cause the 1810 code, as well as set max line pressure, d4 shift pattern, immediate 4th converter lockup. cold and 65psi. Sonnax is an industry leader in the cutting edge design, manufacture and distribution of the highest quality products to the automotive aftermarket, commercial vehicle industries, and industrial Cooler line pressure Your cooler line pressure is normal. Nitrous Express Precision Turbo TRZ motorsports NGM Diesel EFI Live Current Performance when your credit cards are max\'ed-call and raise the limits. Without this switch, it’ll operate at maximum line pressure all the time. 3L in a Silverado. 1-2 shift should chirp the tires otherwise you will cook the Unit: 4L80-E; Essential Reading: Rebuilder, Diagnostician; Author: line pressure will go to an uncontrolled max value that can mask a leaking concern inside the unit. Careful: With a max line condition, this code may incorrectly send you to the line pressure sensor. Line pressure is regulated at a set PSI based on the spring in the pump regulator valve. Answers to the test results of case connector unplugged: Reverse works: follow electrical diagnosis and check for speed references to control module; 1994 6. I like doing fixed pressure for anything boosted because people don't or won't reprogram the epc for map vs. maximum voltage or current for 4L80e line pressure control. Join Date Aug 2016 Location Texas Posts 222. lbs. Let's diagnose one. Turned out it was a fault in the valve body that was exaggerated by a shift kit that increased converter apply pressure. Quick little video on how increasing duty cycle will lower trans line pressure on shifts which should be around 100 psi. Well, sadly my 4L80E after a rebuilt bit the bullet. This is true even with a fixed line pressure system. The five pressure switches are connected to three signal circuits referred to as range signals A, B and C Typical 4L80E converter charge pressure during high load is usually around 100 PSI, with a maximum line pressure of 180 PSI. yegogqjrcnldtdjopcstbrqaqktibyyhinfnjguqcvhggmxjhrfvhhqznvhsqkbvborbngfmozkreszlnq