Transmission problems

My son drives a 2001 Pontiac Grand Prix with 40K miles on it. Earlier this year the transmission went out and a local mechanic rebuilt it and gave us a one year warranty. One month later the transmission went out again. The mechanic says the differential is shot and it is our fault because we put low profile tires on the car. Is this possible? We have had those tires on the car for three years now.

So the same tires are on the car now that were there when he gave you the 1 year warranty?

He just doesn’t want to make good on his warranty. You may have to take him to small claims court.

The tires have nothing to do with the problem.

You need a new mechanic.

Describe “went out” when you say the transmission went out. Preferably both times.

When the car was in for repairs we had our winter tires on it. He didn’t see the low profile tires until later on.

I agree but the problem is that I have paid for the job and was given a warranty from his garage. The mechanic had a good reputation but for some reason is trying to get out of keeping his agreement.

When the transmission went out the first time. it stopped shifting, the check engine light came on, and the car would start off sluggishly from a dead stop. The mechanic said the gears in the primary were shot.

When we took the car back a few weeks later it was shifting poorly and a check engine light came on. I connected a code reader that said the torque converter clutch was stuck.

The mechanic dropped the pan and found metal debris. He tore the unit apart and found the gears stripped in the differential.

No, the tires did not make the final drive grenade. It sounds more like lack of lube from something he did.


I would want him to show me the damaged differential parts, I would look to see if damage appears to be from lack of lubrication or from a tolerence incorrectly set.

If the tires were on the car at the time of the first rebuild then 2 things, the mechanic who objected to them should have mentioned it then, and the cumulative effect of whatever problem this mechanic says has now damaged your transmission would have been evident during the inital rebuild.