#02-07-30-039C Firm Transmission Shifts, Shudder/Chuggle, Transmission Wont Downshift [Archive] - GrandAmGT.com Forum


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09-26-2003, 10:04 AM
Firm Transmission Shifts, Shudder/Chuggle, Transmission Wont Downshift on Deceleration, Service Engine Soon Light Illuminated, DTC P0742 Set (Perform Diagnostics and Replace TCC PWM Solenoid) #02-07-30-039C - (06/12/2003)
Firm Transmission Shifts, Shudder/Chuggle, Transmission Won't Downshift On Deceleration, Service Engine Soon Light Illuminated, DTC P0742 Set (Perform Diagnostics and Replace TCC PWM Solenoid)
2003 Buick Century, LeSabre, Park Avenue, Regal, Rendezvous

2003 Cadillac DeVille, Seville

2003 Chevrolet Cavalier, Impala, Malibu, Monte Carlo, Venture

2003 Oldsmobile Alero, Aurora, Silhouette

2003 Pontiac Aztek, Bonneville, Grand Prix, Grand Am, Montana, Sunfire

with 4T65E Transaxle (RPOs MN3, MN7, M15, M76), 4T40E/4T45E Transaxle (RPOs MN4 or MN5) or 4T80E Transaxle (RPO MH1)

with Transaxle Manufacturing Julian Dates Between 219 and 3048

This bulletin is being revised to clarify information regarding the 4T80E transaxle. Please discard Corporate Bulletin Number 02-07-30-039B (Section 07-Transmission/Transaxle).

Some customers may comment that the transmission shifts hard, a shudder/chuggle is felt on deceleration or the Service Engine Soon (SES) light is illuminated.

A technician may find DTC P0742 set.

Customers with 4T80E transaxles may also comment on a "bump" feeling at approximately 61-68 km/h (38-42 mph) when they lift and then tip into the throttle. There may also be a concern of whine noise in 3rd or 4th gear with or without the Service Engine Soon light/message displayed and with DTC P0742 set.


This test is not applicable to the 4T80E transmission. Instead, replace the TCC PWM solenoid on vehicles with a 4T80E transmission using published procedures for the vehicle being serviced.

Perform one of the following diagnostics:

Test drive the vehicle with the Tech 2 installed, Monitor Transmission Release Pressure. The Status will be YES until TCC applies and then the display will read NO. If during acceleration the status remains NO and the upshifts are harsh and during deceleration the vehicle shudders during downshifts, suspect the TCC PWM solenoid.
With the Tech 2 installed in the vehicle, start the engine. Build the vehicle on the Tech 2. Apply and firmly hold the service brake. Place the transaxle in D4 and command Drive 3 with the Tech 2. If the engine stumbles and/or stalls, suspect the TCC PWM solenoid.
Replace the TCC PWM solenoid using published procedures for the vehicle being serviced.

Parts Information
Transaxle Model
Part Number

Valve Assembly


Valve Assembly

11-05-2003, 12:08 PM
It isn't mentioned specifically, but this is almost exactly what I'm experiencing.

I have a 2000 Grand Am GT sedan. Does this TSB extend to that year as well?

A bump/wheel hop sensation on acceleration and a vibration intermittently at times (when slowing to a stop and then accelerating before a full stop is achieved).

Will this be covered even though I'm no longer under warranty, and if not is it an expensive fix?



11-08-2003, 07:55 PM
Hmm, yeah, my car has done that too, the whole front end feels like it just ran over a speedbump when you know it is completely flat, when its done it for me its 1/2 throttle to WOT. I don't know what to think about that, anyone else know? or comments on whether this happens to anyone else?

11-10-2003, 09:41 AM
You know, I was going to ask about this at some point or another too! Mine shifts real hard when the engine is cold, but it shifts firm even with it warmed up. Thats why i've been so scared to throw an shift kit on that thing. I haven't felt any chuggle or shudder on deceleration though.

11-10-2003, 10:39 AM
For me, it's not so much on the decel that it happens, but more when you reapply the accelerator. It's that transition from slowing down to accelerating where you feel the shudder.

I also feel the "wheel hop" type sensation mentioned above. Seems like it happens when I'm at a dead stop and give it some gas, not flooring it mind you but what I'd call mildly agressive acceleration.

The whole car seems to jump and then settles back down. At first, I thought it was the tires slipping and the traction control kicking in to limit the wheelspin, but sometime after this started, I noticed the "Low Trac" light didn't come on when this happened. To test it, I switched off ETS and tried to duplicate the problem, it does happen when ETS is off so it shouldn't be traction control.

I took the car into the dealership last week. They in fact (with no mention of the TSB from me) diagnosed the problem as related to a solenoid. The bad news was that they told me that (in addition to the 1.5hr diagnosis time) that the repair job would require 7.5hrs repair time and that even though the part was only $82.00 Canadian, the entire job would cost me close to $1000.00 Canadian to fix. They advised me that I could drive the car like this for now, but if left unrepaired, it would eventually do this at all speeds in all gears.

After haggling with GM for two days, they agreed to fix the problem as though I had purchased the extended warranty. I will pay the $100.00 deductible and they will cover the rest. It helped that I told them that this was my 3rd GM car and that I'd only been to GM service technicians for all service and maintenance (down to oil changes) ... that and the fact that I had reported hard shifting while I still had 10,000 km on my warranty that they were unable to duplicate at the time.

Also interesting was the fact that the dealership told me the repair time would be 7.5 hrs labour, and the GM rep I spoke with said that I would pay the deductible and that they would cover the 5.5 hr shop cost.

Seems to me that the dealership was trying to hose me for 2 unneeded hours of labour. This will be the last time I go back to them because of that. Problem is I'm having trouble finding a quality GM service station. Up to this point I had only had warranty work done there and thought they were good, after learning about the price discrepancy from GM, they have now lost my trust.