Limited Slip additive - cause differential failure???

[reesmicm]

Could "not adding" the limited slip differential additive with a Castrol gear change to the differential cause a bearing failure? 97 4Runner V6 2WD automatic(gear lube changed at 53k, no noise, now at 60k lots of gear wine)


where would I find if my differential is limited slip?

 

[KB084RUNNER]

How do you know it is a bearing failure?
Why gear whine if the bearing is bad?
Which Castrol product did you use?

 

[AK Mule]

If you have a limited slip diff, the additive helps the clutches disengage to prevent "chattering" around corners. The chattering is a stuttering feel like the two rear tires are fighting each other. You may also get a moaning sound on slow tight turns. Some say this is only noise and not harmful. I'll leave that discussion open.

The additive alone should not affect bearings at all. The additive is not a lubricant. If there is noise driving in a straight line, it may be the differential, but not the limited slip function of it. Pinion bearing, carrier bearings, wheel bearings can all go bad, irrelevant of LS additive, but not adding the additive is probably not related, IF it is a bearing.

A good shop should help you isolate where and what is making the noise and go from there. If the only change you know of is the diff fluid change, go back and analyze what fluid was used and the the procedure of changing it.

Best of luck!

 

[reesmicm]

Lsd

The differential fluid was changed by my Toyota dealer at 53k with 3 quantity of Castro gear lube (#8090), no additives added. We had zero wine before we had it changed, I just had them change it since I was getting the auto transmission changd too. The whine progressive got worse, went back at 60,895 to the dealer (should have went back at 59,999 - would be under warranty). They said I needed to replace the carrier bearing assembly at the cost of around $1500. I didn't check the fluid level before I brought it back in (should of), don't know if they actually put enough gear lube in when they changed it.

 

[AK Mule]

So the dealer may have diagnosed it to the carrier bearing assembly. For the quoted cost, he is saying the whole assembly, not just the carrier bearings. Ask him for a breakdown on parts and labor. Has he provided any info on why it went bad at only 60K miles? Without pulling the diff apart to inspect, that may only be part of the story. It may be exactly as quoted or something else once it is apart.

I would talk to the service manager about a possible goodwill break on the price, since you are barely past warranty. If they can't budge on price, look into other differential shops in town (since you are out of warranty), and have them diagnose and quote you a price.

Choices - dealer fix it for full price, dealer fix it for goodwill price, other shop fix it. Important to get some feedback on "why" it went bad.

Not something you want to let go for too long. Best of luck.