200 psi at idle
Thread Starter
TECH Apprentice
Joined: Jun 2009
Posts: 318
Likes: 5
From: Oklahoma
200 psi at idle So, I've had a **** load of issues with my( built )transmission. The first guy turned the EPC noid up a full turn. The shop that built it the 2nd time never checked the line pressure and exoded 4-5 pumps. Shifts 1-2 great but 2-3 TOTALY sucks. You can feel the slow *** shift. They say they will change the drum and that should fix it. ( agin )
My question is: what would cause a very f'n slow 2-3 shift and soft 3-4 shift. Is something busted? The car is a 2000 TransAm, lq4 with a PTC converter. The transmission has a TransGo HD 2 kit. New clutches & drums. I'm sick of dumping cash into it. Please help
My question is: what would cause a very f'n slow 2-3 shift and soft 3-4 shift. Is something busted? The car is a 2000 TransAm, lq4 with a PTC converter. The transmission has a TransGo HD 2 kit. New clutches & drums. I'm sick of dumping cash into it. Please help
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
I see that no one else had replied yet, probably because the trans builders are thinking "good grief where do I start".
First, the over-high pressure at idle needs to be fixed. With the HD2 kit, you should have somewhere around 125 at idle in Park/Neutral/Drive and around 200-225 in Reverse or when you blip the throttle. Sounds like the EPC solenoid is messed up and is commanding max pressure at all times; not good. Alternatively, if you have a 2007 or later trans, the HD2 boost valve needs to be installed differently; tell me if that is the case.
The 2-3 and 3-4 shifts are NEVER as crisp as the 1-2. They should seem fast, but without the snap. If the 2-3 really is slow and sloppy, the possible reasons are:
* Worn out 3/4 clutches.
* Leak of 3/4 fluid in the input drum
* Leak of 3/4 fluid in the servo assembly
* Leak of 3/4 fluid past the 3rd accumulator check ball
* Leak of 3/4 fluid in the 3/4 accumulator
* Insufficient size 3rd fluid hole in the separator plate
(HD2 kit specifies .092 which is sufficient, but can go up to .125)
A good rebuilder will check everything to ensure there is no 3/4 leakage, make sure the 3/4 clutches are of good quality and have the proper clearance. There are too many details to cover here.
First, the over-high pressure at idle needs to be fixed. With the HD2 kit, you should have somewhere around 125 at idle in Park/Neutral/Drive and around 200-225 in Reverse or when you blip the throttle. Sounds like the EPC solenoid is messed up and is commanding max pressure at all times; not good. Alternatively, if you have a 2007 or later trans, the HD2 boost valve needs to be installed differently; tell me if that is the case.
The 2-3 and 3-4 shifts are NEVER as crisp as the 1-2. They should seem fast, but without the snap. If the 2-3 really is slow and sloppy, the possible reasons are:
* Worn out 3/4 clutches.
* Leak of 3/4 fluid in the input drum
* Leak of 3/4 fluid in the servo assembly
* Leak of 3/4 fluid past the 3rd accumulator check ball
* Leak of 3/4 fluid in the 3/4 accumulator
* Insufficient size 3rd fluid hole in the separator plate
(HD2 kit specifies .092 which is sufficient, but can go up to .125)
A good rebuilder will check everything to ensure there is no 3/4 leakage, make sure the 3/4 clutches are of good quality and have the proper clearance. There are too many details to cover here.
Thread Starter
TECH Apprentice
Joined: Jun 2009
Posts: 318
Likes: 5
From: Oklahoma
I turned the epc down a complete turn. Pressure now at idle is 95. The Transmission case is from a 98 as my original case was so scared up it was unusable. Does this help?
Thanks for the reply.
Thanks for the reply.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Glad to hear you got the idle pressure fixed.
Keep in mind that a high-stall converter makes the shifts feel softer.
You might need an experienced trans expert or tuner to tell you whether your 2-3 shift is OK.
Keep in mind that a high-stall converter makes the shifts feel softer.
You might need an experienced trans expert or tuner to tell you whether your 2-3 shift is OK.
