My car became totally inoperable after the repair shop changed the timing belt and performed the 90k service (including transmission flush). The car vibrated pretty badly at idle on day 1 we drove it. RPM jumped by itself at idle. Took the car back three times, and the issue was not fixed. After the third time, the shop told us that the transmission was dead.

Our car was in great driving condition before the service. Now the transmission was dead and the car also has another 2 engine codes. We were very upset. What the shop did could have caused the transmission to fail? Your advice is highlyh appreciated.

 

Its hard to tell. First instinct is to assume that the timing belt was installed incorrectly. Although it is running, if the belt is off one tooth, it will not run correctly. If you havent done regular services (we recommend every 30K at my shop) on the trans it could in fact be hurt. I've seen cars with no issues come in for a flush, and leave wounded. The probelm is the fluid develops almost a varnish after so long and the detergents in the new trans fluid clean it off rendering the clutches nearly useless. Though transmission malfunction is a possibility and can make a cvar stall, I've not seen a one affect engine idle speed. I would make sure that the shop double checked the belt installation and didnt just wing it in a attempt to sell more service. I know when i did the t-belt on my freinds SVt focus the crank pulley jumped 1 tooth. It ran but had no bottom end and choppy idle. Thats where I would start.

 

It's been my experience that a Transmission Flush is the worst thing you can do to a High Mileage car. Apparently, flushing the tranny "loosens" things up that were being held by the very "gunk" you're trying to get rid of, causes clutch-packs to slip and generally reaks havoc. I'm not a Transmission expert but that's what I was told. I did it to a car I had that had 120,000 miles on it and the Tranny was toast within 3 weeks. Unfortunately, the shop that did it said they only did what I told them to do and they can't be to blame if my tranny was old and tired.

The other engine codes and the roughness at idle may also be a result of the tranny problem.The engine may be working harder than it should to move the transmission so the ECU is confused and doesn't know exactly what to do. Sorry to be the bearer ofpossibly bad news. Good luck. Wish I could help more.