NJNETSFAN

iTrader: (15)

I used the old servo, but I did take it apart to install new springs and did jam the pin at one point and needed to use some force to get the pin free so there's a good chance that I damaged it during that time. Hopefully I'll know more on thursday if the weather is good enough to take the car for a short ride and then I can begin taking the trans out this weekend.

NJNETSFAN

iTrader: (15)

Ran the test on jack stands today since I couldn''t find a good way to route the pressure line away from the exhaust.

Idle- 65psi
Reverse-75 psi
Brake stall in drive(1st gear, 4k rpm): 100 psi

On shutdown, I see the gauge spike to 200 psi..is this normal?

clinebarger

Reverse pressure is way low, Idle is normal.

You need to apply 100% load, But looks like pressure boost issues... Try D2 & Low to see if it will Boost. Hell....Unplug the trans, Raise the RPM, Keep it short!

NJNETSFAN

iTrader: (15)

I should have mentioned that I tried in D1 and D2 and pressure never went above 100psi. So you want me to put it in drive and unplug the trans electrical connection?

mrvedit

Unplugging the trans will put it in "limp mode" which is 3rd gear, but also should give you max line pressure.
It seems like the boost valve/system is not working. In reverse, the boost valve should move in its bore to give you very high pressure, around 175 psi. Either the pump cannot provide the pressure, there are major leaks or the boost valve is defective or its bore worn.
Sorry, don't time to reread this thread - did you install a shift kit and/or boost valve?

NJNETSFAN

iTrader: (15)

Well I think I have some good news.

With the trans unplugged,

I am getting 275 psi in Reverse and 200 psi in all other gears(1,2,3)

The trans was supposed to have a HD2 kit in it before I tore into it and what was in the trans before was put back in, so the boost system should have HD2 components in it.

I am assuming this is indicating something electrically is damaged.

clinebarger

Plug the trans back in & retest, The Boost Valve &/or Regulator could have been stuck, And you could have freed it up....

We now know your Pump Output is OK, And something in the Boost control is/was wrong.

Reverse Boost is purely hydraulic, There are 2 "reaction" areas of the Boost Valve/Sleeve assembly, One for EPC Boost (Controlled by the EPC), And one for Reverse that gets its signal directly from the Manual valve.....It should boost in reverse no matter what the EPC/AFL/Electrical is doing.

I was looking at some of your pics, The Pump Body pic....I can see clutch material still there after you installed the new Primer spring. This tells me you are not washing/cleaning your parts correctly/thoroughly.

Not trying to be an ***....But you HAVE TO be thorough or this thing is never going to be right.

NJNETSFAN

iTrader: (15)

Just tested the trans line pressure unplugged and plugged in back to back.

Unplugged line pressure was at 275psi in Reverse and 200 in all other PRNDL positions.

Plugged in, line pressure was at 100-110psi in Reverse and 60 in all other PRNDL positions.

It should be noted that pressure doesn't really rise when in gear and power braking.

mrvedit

Strange result that connecting the PCM would reduce the line pressure in Reverse. Looking at the hydraulics, don't see how that is possible.

I would suggest dropping the pan and removing the boost valve to be sure it is all assembled correctly. Personally I would replace whatever is there with the Sonnax 4L60E-LB1 boost valve to be sure you have the correct parts; also this has o-ring to seal even in worn bores. If you agree, order the Sonnax ahead of time.

My current hypothesis is that the boost valve is so loose (or incorrectly installed) that the reverse and boost circuits are cross-leaking and giving these unusual results.

coryforsenate

iTrader: (1)

Is it possible the boost valve for the wrong year was installed? I know when I purchased one from Sonnax the instructions were very clear that installing the wrong one of the two available would cause a lot of problems. No idea what problems those would be though.

NJNETSFAN

iTrader: (15)

The Sonnax 4L60E-LB1 boost valve will be here in a couple of days thanks to NJmooch hooking me up with one. In the mean time I'll see if I can drop the pan before it gets here.

mrvedit

Fingeres crossed this fixes your problem.
You just need snap ring pliers to drop the existing boost valve.
After removing the snap ring and cover, the boost valve, sleeve and spring should drop out. There is a control valve above the spring, but it generally does not drop out on its own.

NJmooch

Anything happen? Did you install the LB1? Update!!!!

NJNETSFAN

iTrader: (15)

I got the LB1 yesterday in the mail. I went to start working on the car today and ran out of propane for the heater about 20 minutes in so all I was able to do was drain some of the fluid via the cooler lines. I've got family visiting this weekend so the next time I'll be able to work on the car is Tuesday. I will post an update as soon as the car is running again. Thanks again NJmooch for the LB1!

Dynamic396

Your transmission hydraulics are working just fine, including the boost valve. Replacing it with another one won't fix anything. If you're getting full line pressure with the transmission unplugged, but when you plug it in, you're only seeing base line pressure in forward with some R/I boost in reverse, you have an electronic problem.

For whatever reason, the PCM is commanding the EPC solenoid closed, and never commanding any EPC boost. What that reason is...? That's the fun part...! You get to go find it.

clinebarger

The EPC doesn't effect Reverse Boost, The EPC amps will hover around 1.00 Amps (Minimum regulated pressure) in Reverse. And his reverse boost is way low, And little Torque Signal/EPC boost. Those junk trans-go boost valves can cause weird **** like this because the sloppy machining....Usually when the unit is hot though?? However if the Bushing fits loose in the Pump Cover, & the Boost Valve is loose in the Bushing.....Burning the candle at both ends!

If he has a capable scan tool, & a Amp Meter....He can verify EPC operation pretty easy.

mrvedit

As Clinebarger says, its the low Reverse pressure which makes me suspect the Boost valve.
Sure, a screwed up PCM or strangely shorted harness might be causing this problem too, so lets call it 50/50 boost valve or PCM. Since the boost valve is only $25 and easy to replace, I like to suggest the cheapest/easiest repair which has a reasonable chance of working. Heck even if I thought it was 20% Boost valve, 80% PCM, I would suggest changing the boost valve first, because replacing the PCM is more expensive and can be a pain.

Dynamic396

EPC doesn't effect reverse boost? Do you mean it's not in this particular case, or in general...? Because the EPC absolutely boosts line pressure in reverse! You get a small increase in line pressure in reverse when R/I oil acts on the large land of the boost valve relative to the small one, which is not a very large influence. He's clearly getting that bump from R/I oil both with it plugged in and unplugged.

I do agree that Transgo's stuff is junk, but the problem lies elsewhere...

mrvedit

You may very well be right Dynamic396 and your insight and detailed explanation is very much appreciated.
It appears the OP will first replace the boost valve and if nothing else, he will benefit from having the best one. If that doesn't solve it, we can then all help him with further diagnosis. Fortunately he already has a pressure gauge and hopefully can acquire a scanner that can control the pressure.

Dynamic396

I don't understand why you guys think reverse pressure is low. 275 psi is plenty healthy, especially in a car. Heck, I'd be happy with 275 in a truck application...

If the pump, existing boost valve, AFL regulator and EPC solenoid is capable of making 200 without R/I and 275 in reverse (with R/I), that is working correctly, and his problem lies elsewhere.

"Best one" when describing the Sonnax boost valve is debatable, I guess. I just don't tend to worship at the Sonnax altar as much as some, I guess...