Chattering/Shimmy from rear differential

Hello All,
I noticed recently a weird chattering/shimmy at very low speed (while turning in a drive thru then parking the truck back at work). I first thought it could possibly be the U-joints bad but I checked them & they appear to be fine. While going back & forth in fwd & reverse with the front wheels turned hard left I noticed (and felt) the chattering & shimmy coming from the rear left wheel. I also checked lug nuts which are tight. I changed the differential fluid nearly 15,000 miles ago with Valvoline 75-90 + 4oz. of trans x posi trac lsd additive with no issues up until now. I do not tow often & have not towed anything since changing the fluid. I checked the fluid already & it oozed out slightly & appeared to be very clean so I'm thinking maybe it just needs new LSD additive. I plan to change the fluid out completely & add new additive as well to see if that helps. I just wanted opinions from you guys & maybe even similar issues/remedies experienced if there are some. Thanks in advance!!

 

I hope you don't mean 4wd on dry pavement.

 

Nope, I have the PreRunner.

 

Check the tightness of your u bolts

 

good idea! I checked them though and they are good & snug...same symptoms.

 

Have you greased your u joints?

 

It sounds like you have some chatter from your rear diff. Your truck has a mechanical limited slip rear diff. That means when changing your diff fluid you need to add limited slip additive. I would suggest changing your rear diff fluid and use either GM or Fords limited slip diff additive, they work best. You could also use the Toyota stuff but it's very expensive. Hope this helps good luck.

oops just noticed you know about the diff additive maybe I should read the whole post before replying

 

I'm going to go with Amsoil Severe gear oil & LSD additive, I've read it's great stuff & lasts quite awhile, we'll see how it goes.

 

LOL, I did add the diff additive the last time but I'm going to use a better quality diff oil this time around (AMSOIL SEVERE GEAR) which is rated for 50,000 miles severe use & 100,000 miles normal use. Valvoline didn't cut it!!

 

Its synthethic oil making all that ratched. Let us know if that Amsoil works. If not. try Lucas. I gave up on making that LSD work with synthetic.
For the money I spent of various synthetic oils I could have regular oil changed every 12 000 miles for the rest of the trucks life

 

6 months after I bought my Tacoma it started a nasty vibration in rear diff, needed a new rear diff(warranty). New diff installed and 2 months later the 2nd rear diff started making the same noise you're describing, took Tacoma back to dealer now I am on my 3rd rear diff. I have 151,000 miles on truck and no more rear diff issues.

 

It is very good stuff and their additive is also excellent. I have it in my 07 Tacoma and 2003 Tahoe. I would recommend 75-110 if you tow frequently. If not the 75-90 SG is great.

Of course im biased I sell the stuff. lol

 

I will be changing the oil this Fri, & I believe I found a dealer for it in the local area so I will be calling him up. I read great things about Amsoil & Redline so I'm hoping it will cure my problem & last me a LONG time. TY for your reassurance!

 

Definitely sounds like the LSD chattering. My 07 did the same thing when i went to synthetic, had to go back to standard oil. Flush it out and make sure you put the LSD additive in there.

 

Will do!! I appreciate everyone's help & advice, I really hope the fluid change will solve my problem.

 

I have a 2008 2.7l base, do I have an LSD. Just did a diff fluid change today, and I used Mobil 1 75w90 gear oil. Took all 4 quarts and just started to come out of the filler hole. Do I need an LSD additive?

 

I use Valvoline Durablend in my LSD rear diff and added 2oz of LSD additive. No issues.
Did you use plain Valvoline no additive or Durablend?
Durablend has 3% LSD additive in it, Toyota calls for 4%.

4% = 3.84 oz of additive
3% = 2.88 oz of additive
5% = 4.80 oz of additive

When I added 2oz more it put me at 5%.
I probably could of went with 1.5 oz which would put me at 4.5%.

When using your favorite brand check to see if it has any additive in it and what % there is.

 

I thought the 8.4" rear diff only held 3 quarts... How'd you get 4 quarts in there? Was the truck level when you changed the oil?

If you have a mechanical limited slip differential, then yes, you need to use the additive. There should be a sticker or tag on the rear diff saying that it has a mechanical LSD and the friction modifier is required.