@Rod Knox: My transmission has never jumped out of gear. The only symptom is the low grinding noise when the car is driving.
Okay, time to profess my ignorance. Now that the car is in the shop, the mechanic says he thinks the noise is coming from the differential. How is this related to the transmission? I will know for sure what has failed on Monday, but I like to understand things about cars in the meantime.
On front wheel drives the differential is incorporated into the transmission but can be serviced separately on some cars. On many a failed differential would be best repaired by replacing the entire transmission with a used unit.
You’re misinterpreting me susanrm. I’m not trying for one second to paint you as incompent.
What I am pointing out is that many car problems have root causes that are owner inflicted. The problem with your transmission has gone from mainshaft bearings to a possible bad differential at this point with still no clarity.
You have stated that you have had every required maintenance performed at specified intervals and I take your word on that without hesitation. The issue is not with what you’re telling me; it’s with what was actually done by the facility that was providing those maintenance services.
If all maintenance intervals were performed as required then you should have copies of the repair orders. On each repair order for the specified transmission oil change intervals the transmission oil should be shown as a separate charge on that ticket.
So the question is this. Do your copies of the repair orders actually show any labor operation for a transmission oil change or in the event of a set hourly time for the entire maintenance service does the repair order show transmission oil being charged out?
If it’s not on there then it wasn’t done.
There are bearings, gears, and shafts in the differential. As another post said all these components on a FWD car are housed either in or very close to the transmission so in effect it all looks like one unit from the outside casing.
What is a bit confusing is the change in the noise when the clutch is depressed and the car is moving. The transmission gears don’t stop when the clutch is depressed as long as the wheels of the car are moving. But the torque on the transmission (or stress) is greatly reduced and the transmission is in effect coasting along as the wheels spin. The same change in torque would have the same kind of effect on the differential as it is also spinning if the wheels are turning.
My guess is the noise is reduced when you depress the clutch with the vehicle moving but it is still making noise. That noise is just much less and is masked by other ambient noise from tires rolling and the motor, etc.
Bottom line, it could be a differential problem and the mechanic is just going to have to get in there and find out what’s going on.
Another link with interesting reading: http://www.carcomplaints.com/Toyota/Corolla/2003/transmission/transmission_and_differential_failure.shtml
@ok4450 - I have all the receipts, just no time to go through them all to answer your question! But for the first, oh, maybe 80,000 miles I had the car, all the service was done at the dealer, so they should have done the oil change at the very least. Again, this is not my problem. It is a pervasive one with a high “lemon” rating.
Finally got the verdict from the transmission shop. They said they found three bearings that went bad - they were making noise and allowed extra play in the shaft that passes through the hole, which caused the differential to break.
There were also two mounts that were broken. The synchros were too dulled to reuse, even though he also admitted the car still drives very well and shifts easily.
The transmission rebuild, new clutch (old one is okay, but is also fine to replace), new differential, and new mounts will add up to just under $3,000, with a 12-month, unlimited mile warranty. If I were to get a whole new transmission, it would be about $4,000 with only a 6-month warranty from the dealer.
I decided to go with the rebuild after speaking with the shop manager, who told me that the car is so well maintained and tight despite the mileage, and with little rust, that it should be okay for a while (fingers crossed). He also said they found no sign that any driver abuse or neglect caused any of the problems.
The parts shop subbed in the bearings for a six-speed, saying they were interchangeable and better built than the parts specified for the five speed.
…I think “thingies” should be “shaft”…