tranny

[Booreatta]

Who knows the model of the transmission that GM put in the 84 Riviera. I have had mine rebuilt and I still have a few issues. I want to trouble shoot it myself but I need to know what the model number is.

Thanks

[RivNut]

325-4L. I understand that this is the FWD version of the 200-4R.

[sosuzguy]

We've been discussing this on and off for a few months now if you'd like to catch up at this thread.

http://forums.aaca.org/f177/transmission-rebuild-1985-a-281300.html

[Booreatta]

We've been discussing this on and off for a few months now if you'd like to catch up at this thread.

http://forums.aaca.org/f177/transmission-rebuild-1985-a-281300.html

Jayson I thought that I had my issues solved, but no still some issues. I am to the point of selling the car, It just consumes my time. I thought it was going to be ok but I had the car up in Ames and it just is not correct. Oh well I will keep trying

[sosuzguy]

What is it doing?

[Booreatta]

Jayson its the same ol thing. I had it rebuilt and it seemed to be working fine, I put on a couple of hundred miles and now it is shifting ok from 1st to 2nd then each shift after that is a studder shift. The down shift is lousy and it is in lock up and out of lock up and acts like a miss in the motor. I tuned the motor to see if that would make a difference and it did not. I am convinced that it is in the Throttle Valve somewhere. If this keeps up I will try to find a new tranny and see if that makes a difference but I am tired of throwing money at it and getting nowhere.

The car only has less than 60000 miles and is in good shape except the trany. I just cant trust it to put it on the road. So ???????

I know we have talked about this before, so I keep trying in hopes the problem can be resolved.

Thanks

Chuck

[Guest pfloro]

Chuck:

Let's try to isolate the cause of the poor quality shifts. From what you are describing, it sounds like the TCC (Torque Converter Clutch) might be involved.

Disconnect the TCC connector at the transmission. This will prevent the TCC from ever applying. Take a test drive. Is there any difference in the quality of the 1-2, 2-3 and 3-4 shifts? What about the forced downshifts? What about the engine miss you described? Even if the problem still exists, it could be a defective TCC solenoid. I understand they can hang up & not release even when power is removed.

Let's assume the problem goes away when the TCC is disconnected...

This is my logic: If the ECM is malfunctioning and applying the TCC at the wrong time, both the upshifts & downshifts will be poor. Even if you 'hot wired' the TCC solenoid to permanently energize it, the 325-4L will not lockup the torque converter until after the trans shifts into 2nd. No lockup hydraulic pressure is available until the intermediate servo applies (2nd gear). But if you have lockup too early (for example, as soon as 2nd gear occurs), the 2-3 and 3-4 shifts will be abrupt. This is because the shifts are not cushioned by the trans fluid (direct coupling now exists between the crankshaft & the transmission).

By design, the TCC is not meant to lockup until the car is in a steady cruising state above a certain speed. The ECM uses the inputs from various sensors to determine the lockup (& unlock) point. Vehicle speed, throttle position, engine vacuum and temperature are all involved in the ECM's decision.

Since you mentioned 'it is in lockup and out of lockup', let's try another test. Reconnect the TCC connector. Take a test drive & cruise on a level road at about 45 - 50. The TCC should apply at about 40 and remain applied unless you apply throttle to accelerate. If the TCC randomly releases & re-applies, the very likely culprit is the TPS (Throttle Position Sensor). As they age, the resistive material wears out & the TPS develops electrical 'opens'. This fools the ECM into believing that you mashed the accelerator to the floor. The ECM responds by unlocking the TCC. Once the electrical connection within the TPS becomes normal, the ECM will re-apply the TCC. Until the TPS really gets bad, the ECM will not set trouble code '21' and turn on the Check Engine light. You might want to 'flash out' any stored codes and see if a '21' is in memory.

I have been around the block with worn out & defective TPS sensors many times in the 26 years (192,000 miles) I've driven my '84 Toronado. IMHO, the TPS sensor is the weak link in GM's first generation CCC (Computer Command Control) when used with the DualJet or QuadraJet carburetor.

Keep us posted,

Paul

Edited August 15, 2010 by pfloro (see edit history)

[RivNut]

Chuck,

Read this thread and see if your problems sound familiar. The downshift part sounds like a TCC solenoid (Torque Converter Clutch). If the torque converter is locked, you could have problems on your upshift as well.

http://forums.aaca.org/f177/problems-my-85-307-a-283969.html

[Booreatta]

You guys are really great, once again I am printing off all of the info that you all have supplied and taking it to my tranny guy. Lets see what he comes up. I will keep everybody posted as to what I find out. I also have found some interesting reading on the web at Bowtie overdrives/TV made EZ the article addreses Throttle Valve Cable system 101. It is more that I understand but a good tranny guy will surely understand it.

Any way thanks so much I appreciate everybodies effort to help me solve my problems

Chuck Kerls

[sosuzguy]

For an update please see my thread here http://forums.aaca.org/f177/transmission-rebuild-1985-a-281300-2.html#post786646 Thanks