75w90 Mobil 1 Synthetic Lube = Axle Whine

I replaced the rear axle lube in my 2002 PreRunner with Mobil 1 Synthetic Gear Lube 4000 miles ago and I now have a "Rrrrrr" sound from the rear axle. Also a "thunk" on right-hand turns.

Axle code is B04A.

As I bought this truck used, I don't know what lube was in the axle previously.

Initially, I thought the "whine" was from the Michelin LTX M&S tires that were installed at the same time. When I removed the Michelins and put the Coopers back on the rear, noise is still there.

It looks like Mobil 1, Royal Purple, and Amsoil do not make a straight 90 weight synthetic gear lube in consumer packaging.

Any suggestions besides going back to 90 weight dino?

 

Weird....I put Mobile 1

$30 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 in my 96 tacoma when I owned it. Never had a problem with it and it was in there for years.

When you changed the oil, what did the used stuff look like?

I even used it in the front & the manual tranny.

 

I have yet to do mine in my 06' but I've been told by numerous people to use some "friction modifier" that comes in a 4oz. little bottle. It is a break-in additive thats supposed to help. But again, I still have about 6,000 more miles to go to change out my diff oil.

 

Do you have a LSD, did you add the additive?

 

I’ve used Mobil 1 motor oil for years, and Amsoil gear lubes and been very pleased with the service I have gotten from them.

This noise after lube change is a new one on me, and it may be that the gears are worn enough that I will have to go back to 90w dino to make things “quiet” again.



Janster:

Yeah, I thought it was odd, also.

The old lube was black, and the drain plug was coated with metal particles. Might have been the original lube, but don’t know that. Truck has 128K miles on it, and I bought it with 115K on it, so not sure how previous owners treated it.

WW_Firefighter:

I think the “friction modifier” is the additive for Limited-Slip axles.

When the rear axle lube on my 2005 Dakota was changed, I told the dealer that the truck had a limited slip axle, and to be sure to add the special additive for that. He kind of blew me off, and I ended taking the truck back and let them hear the chattering from the clutches. They put in the additive and no more problems. Glad to be rid of the Dakota!

Sonjay:

The B04A code indicates no limited slip, as I understand the codes. Thanks for the suggestion.

 

I have a non lsd-non locker third, 95K on a stock truck(Bo4A) also. Switched to mobil one at 92K, drove to and from Georgia back to Florida. No problems. You are in the great white north with more miles than mine has, right? At 92K my differential oil was so clean and the magnetic plug had a "paste" on it but no metal shave/particles on it. My rear end is quiet, no jokes here please, "THAT'S NOT WHAT YOUR GIRLFRIEND SAID!!" There, I beat you all to it. Seriously, I did the rear end, tranmission, front diff and transfer case all at or around 92K on a 1999 Tacoma and there were no metal shavings and the oil was really clean. You might want to look into a set of gears if it gets any worse, also I am not sure if a straight weight oil will quiet it down only to prolong the enivetible. Good Luck Kevin

 

Somewhere on TW there is an oil thread that someone states the multi weight oils are really pushing the limits of their ability to work on the extreme ends of both ranges, example 75W90 doesnt do good at the close end of 75 and the far end of 90 might be pushing it. It's a cheap try to change back to factory, especially if you are in an extreme climate. It's worth a try. Kevin

 

Thanks, monkeysuncle.

I live northwest of DFW in Texas. I did my lube change before a trip to Minnesota last month. Figured the 75w90 would work fine in the cold. A -14 F. was the coldest day, and the truck worked fine, but I was glad to get back to more balmy temps here in North Texas.

The rear end wasn't making any noise that I could hear before the change over to synthetic. I'm thinking now that I will drain the Mobil 1 and switch over to straight 90w dino, and things might go back to "normal".

The PreRunner is used 99% on the highway and gravel roads between town and my place in the country, so no "extreme" off-road situations for me. I like the synthetics for extending the life of things, and possibly getting a bit better mileage.

I appreciate the PreRunner's height off the ground, as it is easier for me to crawl around under and work on. Of course, a good creeper helps!

 

Before changing out the axle lube, I am going to lube the U-Joints.

The sound is not like that of the last 2 trucks I changed out U-Joints on (F-150 4x4), so I didn't really consider those to be a possibility, but I'm having a hard time getting my mind around the idea that switching to synthetic is causing the problem.

Easier to lube them and see if the problem is solved rather than swapping out new axle lube.

Thanks to all for the ideas!

 

im going to be hopefullly doing this tomorrow on my 96 with 126K on it..

Should any 75w90 be ok? non lsd rear end.

 

Hi guys,
I'm new to the forum. My 06 double cab 4x4 has the LS rear diff. I changed the oil/lube this week and installed

$30 Mobil 1 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

Mobil 1 75w-90 LS. I bought this because it is supposed to have the LS additive in it. Since changing, I started getting some shuddering when making a tight turn.

Anyone else have a similar experience?

Do I need to add a separate additive?

Thanks!

 

yes.........you will need to add a bottle of friction modifier to the mobil1. the bottle says its compatible, but apparently, there isnt enough of the friction modifier in the gear oil for the limited slips on the tacomas. quite a few ran into problems using just the oil without adding any additive to it. and from what i hear..its just the mobil1. people have used royal purple in the ls diffs without any problems.