|
Okay, here's the latest update...
I picked up my Tundra from the dealer tonight. I had a really good chat with the tech that's been working on it for the last couple of days. Super nice guy.
He said he's almost certain its a bad bearing inside the front differential. He explained that when you select 4WD, the transfer case locks onto the front driveshaft and there is a "locking sleeve" in the front diff that locks onto one of the front axles. He believes the bearing in or around this locking sleeve is the problem.
Here's what he did:
1. Removed front drive shaft and went for a drive. Hum still there in 2WD but not in 4WD. The front diff still locks onto the axle even with the front driveshaft missing so this eliminated the transfer case from the picture.
2. Removed both front axles. Went for a drive without the axles and the hum was completely gone. This showed that the wheel bearings were okay.
3. Toyota Canada instructed him to replace the diff fluid with a synthetic. He did this, but it made no difference. Apparently there was a case in the US with the same problem where the fluid made a difference.
4. Check various other things too.
So, they're going to go ahead and replace the front differential. Its on order now and will take a week or so to get.
I'll be sure to post an updated on it when it is swapped out.
|