Low trans oil and noise question

Off the top of my head I would say that if it sounds like a bad tire noise it probably isn't related to your transaxle directly. Keep in mind I haven't heard it myself : )

Sometimes wheel bearing noises can be extremely low frequency and sound tirelike. See if the noise seems to change any if you load up one side or the other by cornering. Get the noise to occur as loudly as possible, then turn the steering wheel lightly to the feft, then right. A noticeable change in noise either way would point at a bad wheel bearing.

Keep in mind that the shop may not have drained you transaxle in the first place. Even if it the receipt states it was done, sometimes the service writer just enters on operation code and lines of descriptive text are automatically spit out on your receipt. Some trans. can be pulled down without losing any fluid out of the axle holes. I don't know about yours specifically but you get the picture. They may have lost some fluid out the axle holes and not topped it off. It may have been low in the first place and they did not top it off. Or it may have leaked out and you didn't see the trace of leakage.

But top it off immediately, then determine the cause / fault. It looks like your trans takes 80W90 gear oil. Good luck,

Toyota MDT in MO

I wondered about that and I did try steering left and right to see if it would change the sound at all, but no luck.

The leak is remotely possible, but I know it was full before they did the work; I had changed the oil twice before they did the clutch with the hopes that it would fix the original problem.

Thanks for the reply, I'll try to do that and post the end result.

I did check the receipt and I got charged for gear oil, but strangely not as much as I was charged when I had the oil changed out in my 94 about a year ago. It's like they added some oil, but not enough. It does use 80w90 oil BTW, although they like to use 75w85, probably to make things move a little more smoothly on cold winter mornings. Anyway I will put it to them and see what they have to say. Thanks for the reply.

I would explain your situation to the same service writer that wrote you up for the clutch replacement, or the service manager. Since they actually billed oil out, then that is proof enough that the trans should be full after the job. Its their responsibility (or atleast good business practice) to note any leaks and suggest repair during such a related job.

Be fairly certain that there are no signs of leakage at this time. Its only been two months since the repair. If a leak had occured on its own in that time, then 75 or 80 weight oil stains would most likely still be visible somewhere on the case or frame.

BTW 75 weight is great oil and I don't see a problem with using it if you're in a cold climate. Its harder to find in the nonsynthetic version at autoparts stores though, and the Mobil synthetic prices at about $5 a quart.

Toyota MDT in MO

So I dropped by the dealer today and got one of the guys to take a look and listen at the noise I posted about yesterday. Turns out the fluid level was fine (much to my embarassment, must be on a bit of a slant in the driveway) but he thinks the noise is probably the pinion bearing. He said it was the bearing that the output shaft spins in so it must be one of the mainshaft bearings. Anyway I'm probably looking at around $1000 minus my 10% of labour, just to see if that's the problem, so it's not the best news.. I wonder what else they should look for if they're going to be dismantling the whole thing. Has anyone run into one of these bearings failing before?

In any case it doesn't sound like the kind of thing I'd want to let go for too long, so I'm probably going to have to just take a deep breath and get it done.

So the noise stops when you step on the clutch then? I'd just live with it if you can.

Yes, it stops with the clutch in, or when maintaining a steady speed -- not accelerating or decelerating. I could probably live with it for a while to save a grand, but isn't it likely to only get worse and start leaving shards of itself in the trans fluid?

Not likely. My 300ZX has had a noisy pinion bearing for 50K miles. I don't even hear it anymore. It will get really loud before it grenades.

Find out what kind of bearing it is. If it's a set of rollers that use the shaft for the inner or outer race (or both), you don't want to rack up too many miles or the bearing wear will spread to the shafts. And shafts are NOT cheap. If it's just a cartridge bearing that fits into the transmission casing, you can probably forget it for a while unless the noise increases.

Dave

transmission

Well it seems to me that it has gotten worse in the past few months, but I could just be noticing it more now. Do you guys think the worn bearing would be due to a manufacturing or other defect, or is it more likely due to someone being hard on the tranny? I'm not sure how you would abuse it to cause that kind of failure...

Predicting bearing life is a difficult thing to do. Automotive engineers must choose a compromise between a large, expensive bearing that will last forever at the given loads, or put in a smaller, cheaper, more efficient unit. If the bearing is properly supported and under normal loading conditions, they can still fail sometimes. Grit in the tranny oil, manufacturing defect, etc are possible causes. Statistically a small number will fail sooner than expected.

Don't worry about the 'why' except to ensure that the party who replaces the bearing checks all of the adjustment shims so that the new bearing is operating in a proper setting.

Dave

Well I guess one positive thing about this kind of repair job is that it's a good opportunity to see if there are any other problems inside the trans... From how the tech at the dealer explained it, the whole thing pretty much has to come apart, so when it's all said and done hopefully I shouldn't have to worry about there being any other surprises in there.

I may take it to another place tomorrow just to get their take on it, although the dealer seemed very confident that the pinion bearing was my problem.