I have a 2004 Z71 Tahoe with 105K. The dealer let me know that a bearing in my rear differential is bad. I think it was the pinion bearing. He said there are 6 bearings in the rear differential / rear axle and that I should replace them all at the same time because metal shavings could have damaged the rest of the bearings in the unit. I reluctantly agreed to this for a cost of $1300. Is this legitimate? Should you really replace all of the bearings at the same time?
Yes. In order to replace the pinion bearing the entire differential has to be disaasembled. If it’s been torn down that far and all the bearings are exposed now’s the time to do it. That would be like disassembling an engine for a bad bearing, and only replacing that bad bearing.
There is also a pinion seal that when it leaks is possible to replace, but leaking indicates problems with the bearings and unless you do the whole job you might as well do no job.
Why do this job. Is the car undriveable? Too much noise? At this mileage I would wait and think about a new car or a used replacement differential. If the differential goes bad how much of a pain would it be. These gears are tough but may already be damaged no way to know. If the noise is unbearable this is pricey to fix. This car may not last without more repairs and more money. It could be the start of a money pit.
Rebuilding rear ends can be a nightmare…I would have found a salvage yard replacement for the entire axle for much less money…
Did YOU notice a problem with the rear end or did the dealer “find” it during a fishing expedition you volunteered for? Before pinion bearings fail, the pinion SEAL usually fails, causing a noticeable oil leak…But the seal can be replaced without tearing the entire rear end apart…Most decent gear-boxes have magnetic drain/fill plugs to catch and retain any metal shavings that normally can be found in gear boxes…