Low line pressure 2-3-4
Low line pressure 2-3-4 Got a 60e that loses line pressure in 2nd 3rd and 4th.
Tore trans apart do not see anything obvious.
has a basic Transgo jr shift kit
Tg Boost valve
vette servo
oversize afl
new solenoids
bypassed EPC, still does it.
first gear in Drive, pressure is 200 psi
command 2nd gear with hptuners scanner, drops to 90
command 3rd gear, drops to 50 psi
command 4th gear drops to 90 psi
first gear, reverse, park neutral all good line pressure readings
any ideas?
Looking up hydraulics on atsg PDF and only thing that sorta makes sense is the relay and sequence valve 3-4 4-3 (maroon also recommended this)
I have checked everything else, no issues with bonded pistons, no issues with seals on the servo assembly
no issues with input shaft teflon rings
I air checked the assembly and it all checks
Tore trans apart do not see anything obvious.
has a basic Transgo jr shift kit
Tg Boost valve
vette servo
oversize afl
new solenoids
bypassed EPC, still does it.
first gear in Drive, pressure is 200 psi
command 2nd gear with hptuners scanner, drops to 90
command 3rd gear, drops to 50 psi
command 4th gear drops to 90 psi
first gear, reverse, park neutral all good line pressure readings
any ideas?
Looking up hydraulics on atsg PDF and only thing that sorta makes sense is the relay and sequence valve 3-4 4-3 (maroon also recommended this)
I have checked everything else, no issues with bonded pistons, no issues with seals on the servo assembly
no issues with input shaft teflon rings
I air checked the assembly and it all checks
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Joined: Mar 2023
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From: BERWICK PA
Yes redundent statement but certainly a massive internal leak . And I would agree valve body related as you drop over 100 lbs on the 1-2 shift which would indicate valve body issue. Honestly even if seals were missing or rings damaged I do not think you could get a presure drop that large, I have seen runs on the DYNO with the entire piston missing and even once with the second servo missing and and didnt see presure drop anywhere close to that. As I remeber when someone left a second servo out , 4th was there they had been checking clearance and just forgot after lunch once, The drop was only like 30lbs.
4L60E pumps can move alot of volume.
The only other thing I have seen is the screen missing from pump , Thats can cause the line to be that low but would be all positions pretty much not just after the 1-2 shift.
4L60E pumps can move alot of volume.
The only other thing I have seen is the screen missing from pump , Thats can cause the line to be that low but would be all positions pretty much not just after the 1-2 shift.
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Frank formerly of Performabuilt, Now just me, What can I build for you today? Call or message me. Click sig pic for my facebook
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TECH Junkie
Joined: Dec 2012
Posts: 3,605
Likes: 1,316
From: Iowa
I recommend swapping a different valve body on this case. If it persists, throw the case in the gutter and go find another.
To get everyone up to speed here, OP has verified EPC amps stay the same when shifted to 2nd. And then depinned the EPC and commanded gears with a scanner just to be extra sure there was no funky epc action going on.
Report back what you find!
To get everyone up to speed here, OP has verified EPC amps stay the same when shifted to 2nd. And then depinned the EPC and commanded gears with a scanner just to be extra sure there was no funky epc action going on.
Report back what you find!