'94 LT1 F-Body/ $EE tuning change for '95 transmission (PWM)

**jthompson122183** · 11-04-2016

i have looked at the bin in post 30 and your good to go as far as using "95 pwm code". your problem lies elsewhere.

**Gojira94** · 12-01-2016

Originally Posted by jthompson122183

i have looked at the bin in post 30 and your good to go as far as using "95 pwm code". your problem lies elsewhere.

Thanks for looking at it and apologies for the tardy reply. It's been... busy. With stuff I haven't wanted to deal with. Anyway, I'm thinking my next step will be to pull the harness out of the trans and see if anything unusual was done with it by the unknown builder. Bummer I don't have a known good 95 4L60E lying around, lol. I'll go out on a limb and speculate that maybe the builder put this thing together with something different electronically to sell it to buyers with 94 cars. If the trans was a bill of goods, what I've done should have worked, adding the wire from PCM to PWM solenoid and switching to 95 code.

**Gojira94** · 09-19-2017

I fished the case connector from the trans up to the engine bay. I'm going through the transmission wiring harness with it out of the car, connected up top so I can troubleshoot everything inside the trans as an assembly. It appears to be a reused OE harness because it only has one connector for the 3-2 solenoid. Aftermarket harnesses have 2 for the 3-2; one for 95 solenoid, one for 96-up solenoid connector.

Confirmed the valve body has a 95 casting mark on it so at long last that's confirmed.

All the tuning help I could have needed to address my problems with this thing I got here. Thanks again to all who reviewed my work. I thought I'd at least come back with the outcome. I'll post up the results of the electrical troubleshooting soon.

**Tom B.** · 09-20-2017

You may have a mechanical problem with the PWM valve and bore wear in the valve body. Another issue may be that the PWM (95-newer) transmissions use a different tcc spool valve in the pump. If your trans is a 94 w/a 95 valve body and no tcc valve swap, you can have all kinds of issues w/OD and lock up.

**Gojira94** · 09-20-2017

Originally Posted by Tom B.

You may have a mechanical problem with the PWM valve and bore wear in the valve body. Another issue may be that the PWM (95-newer) transmissions use a different tcc spool valve in the pump. If your trans is a 94 w/a 95 valve body and no tcc valve swap, you can have all kinds of issues w/OD and lock up.

Thanks for offering additional insight! I should have mentioned that the case is a 95 K case and the pump does have PWM stamped on it and it was equipped with a 3-2 control solenoid appropriate for a 95. So on the surface everything seems to match as a 95 aftermarket built transmission. The transmission has about 1000 miles on it at most. I do see some friction material shed into the transmission from being driven with the 3-4 clutches getting extra wear as a result of it being driven by a 94 PCM and no control of the PWM solenoid (now corrected in the 95 tune and extra wire run to control the PWM control solenoid). I'm hoping that no mechanical problems due to wear in the valve body bores has arisen yet. I've accepted that if I get it operating error free, I'll have a transmission with some accelerated wear on it (like 20-30,000 miles of wear in less than 2,000 or something). Maybe higher simulated miles or worse damage than expected.

I'll be getting back to it later today and hopefully have some more answers.

**Gojira94** · 09-21-2017

Values in ohms are:

1-2 shift 21.2
2-3 shift 21.9
Press. Control 4.6
3-2 control 11.4
TCC 23.8
TCC control 11.2

Here's the bench- notice the PCM removed so I can apply voltage down the wire to pin E and ground through the PCM connector pins for each solenoid (except the pressure control solenoid). PCS can be tested with a 9V battery briefly. Testing from PCM down to solenoids gives me more confidence things are working. Honestly, I'm hoping to find something wrong with the harness and just replace it and be done.

**Gojira94** · 09-21-2017

I tested all the solenoids except the PCS, will have to dig up a 9V battery for that one, but I did check the resistance between the PCM pins that go to it (no direct 12V from pin E, only gets signal from PCM).

The 3-2 is the newest solenoid since I replaced it back in 2011 when I first encountered the issues. The PWM solenoid click doesn't sound nearly as stout as the 3-2. They are 2 different manufacturers, the PWM has been in there since before I got the car.

Here's the kicker- the TCC solenoid (built into the harness) does NOT click for me. I can't find a definitive answer as to whether it SHOULD make an audible click, but I'd at least think so. I tested 1-2, 2-3, 3-2, TCC, PWM with IGN239 circuit hot with PCM disconnected and used a small wire to ground the PCM connector pins at each solenoid's PCM location. To eliminate the engine harness I went through the case connector on pins E and T straight off the battery. Again, the TCC solenoid does NOT click. Its resistance is still at 24 ohms after this testing through PCM connectors and direct to battery.