hi im new the this forum i recently purchased a 1995 sc riv and am having tranny issues.It occasionally slips heavily during WOT or after heavy driving which is than accompanied by the ses light.it almost seems like the car is dropping into neutral.It usually only does this until i take my foot off the gas and than works fine however today it would not go back into drive i was basically free revving it until i put it in park and back in drive and than it was fineThe tranny has a very slow leak which i dont think is the cause and it has about 167,000 im getting it scanned tomorrow but if you guys have any thoughts or may know the cause in the mean time i would really like to know thanks in advance

You have to find out what code is being set. Can't help much without it.

Although it kind of sounds like if the tranny has 167K on it and has not had a filter change/flush/fill, you're way overdue. Might want to get it done somewhere where they will use the new Dexron.

Albertj

just got back from mechanics its a qdm1 failure code p1640 iirc what exactly is the quad driver module and how would i go aboiut fixing this problem?also albertj the fluid does not look bad at all and the previous owner was a rabbi who was pretty meticulous with the car so im assuming that the tranny has been serviced in the past.i am however worried to do a drain and filter changeon a car with this many miles because my last car blew the tranny a couple hundred miles after

Found this using google...

ALLDATA.com


DTC P1640 Driver-1-Input High Voltage
Refer to PCM Power and Grounds for wiring view

Circuit Description
The PCM contains chips called Output Driver Modules that provide 7 switchable ground outputs for operating solenoids, relays, telltales, and other devices. Each of these ground outputs has fault lines that feed back to the PCM's microprocessor. ODM #1 can also sense high voltage coming in which might damage the chip. DTC P1640 is used to monitor ODM #1's overvoltage sense line.

Conditions for Setting the DTC
Test Condition
Engine running at least 10 seconds.

Failure Condition
Overvoltage is sensed for 2 seconds.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.
Conditions for Clearing the MIL/DTC

The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test.
Use a scan tool to clear DTCs.
Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.
Diagnostic Aids
Since an overvoltage at ODM #1 should also trigger DTC P0563, the diagnosis for DTC P0563 may be used if vehicle voltage is actually too high.

A loose or faulty connection at generator L terminal may cause DTC P1640 to set intermittently.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.

If ignition voltage and IPC battery voltage are within 1.5 volt of each other, there may be a system voltage problem. If they are not within 1.5 volt of each other, find out why the PCM is different.

Checking if PCM ignition voltage is actually displaying system voltage.



1
Was the Powertrain On Board Diagnostic (OBD) System Check performed?
--
yes- Go to Step 2
no -Go to A Powertrain On Board Diagnostic (OBD) System Check

2
Start and idle the engine.
Using a scan tool note the Ignition 1 display.
Compare this voltage to the voltage displayed by the vehicle message center.
Are PCM and vehicle voltage readings different by more than the value specified?
---1.5 volts
yes - Go to Step 3
no - Fault not present. Refer to Diagnostic Aids

3
Using DVM J 39200 measure voltage to ground on PCM fuse (installed).

Is voltage measured and the Ignition 1 voltages different by more than the value specified?
---1.5 volts
yes - Go to Step 4
no - Perform Charging System Check

4
Check for high resistance in CKT 439.
Repair high resistance if needed.
Was a repair made to CKT 439?
--
yes - Go to Powertrain Control Module Diagnosis for Verify Repair
no - Go to Step 5

5
Check PCM terminal contact at connector C1 terminal 19 and connector C2 terminal 37.
Repair terminal contact if needed.
Was terminal contact repaired?
--
yes - Go to Powertrain Control Module Diagnosis for Verify Repair
no - Go to Step 6

6
Replace the PCM (Go to PCM Replacement/Programming ).

Is the replacement complete?
--
Go to Powertrain Control Module Diagnosis for Verify Repair
--

QDM 2 IIRC covers the
Boost control soleniod
TCC lockup
Evap soleniod
And I forget if there's one more.

Figure that code is probably thrown from the TCC being commanded on and not locking.

I would suggest checking flluid level first. Then the condition of the fluid.

Has the transmission been serviced that you know of? aka drop pan, change filter and replace about 7 quarts of new fluid.

On these cars the TCC solenoid is just a plastic plug and wears out. A good tranny shop can get one made of billet aluminum. My 4T65E transmission TCC failed about 90,000 miles ago. While replacing I also replaced engine's rear main seal and as well put in hi-durability rebuild kit (bands). I have had the tranny flushed and filled twice (about each 40 K miles) since. I do not baby it but I don't race or thrash it either.

That TCC solenoid is a PITA to reach. But when you do replace it suggest you get an aftermarket billet one, not OE plastic. GM may have a billet one too, ask the parts folks, though.

Albertj

I'm having this exact problem with my 95 riv'

Thanks for the information!

Keep in mind the 95 has the 4T60E. I don't know if the solenoids are the same. If they are, this should be it:

http://intense-racing.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IR&Product_Code=GMH-TCCS&Category_Code=T

Thanks for all the help guys the transmission is still doing it i havent had time to post on here in awhile,i turned up the adjusting screw on the vac. modulator to turn up the line pressure during part throttle in case it was a valve sticking or something but it didnt do much but tighten up the shifts i also noticed that it only slips when i break hard into 1st gear an than resume accelerating so im not 100% sure its the tcc solenoid

there was a service bulletin about that, I think - might have to ask a dealer.

Albertj

Turns out my problem was all in the vacuum lines. I noticed some cracks in the old rubbers and one of the lines was split. I put some electrical tape to work, let the car idle for a bit and then took it for a drive. The engine light went out and my car shifts excellently now.

jamie do you know which vacuum line was causing the problem because i havent replaced them all theres a few still that are rotted

I'll go take some pictures. It'll give me a chance to get the riv' online anyhow

edit: Had to use imageshack, as I locked myself out of photobucket with wrong passwords.





I put those two pieces of tape on and all has been well for a few days. I'm hoping that it was the issue. haha.

and yeah, I've gotta touch up on both of those tape attempts.

Just a truthful answer, did I do the right thing by going to aamco to repair all seals axel and fluids and filter and rebuid trans for 2500 even is that a good deal

Aamco is a hit or miss, a full rebuild for $2500 is about average. If the trans holds up over time then you are all set. Nice thing about Aamco is that they have a decent warranty!