Low-Speed Shudder: Rear Diff Issue?

[Extremistno9]

I do have the 3.73 LS with tow package...so add the additive even though RP has it mixed in?

 

[Limited02]

I do have the 3.73 LS with tow package...so add the additive even though RP has it mixed in?

It wouldn't hurt anything to try it.

 

[Extremistno9]

It wouldn't hurt anything to try it.

Thanks for the advice, will do. At this point, I have about 100 miles with no improvement. Gets better as I drive it per outing. However, once it sits for a while, it goes back.

 

[Extremistno9]

I added the friction modifier to the Royal Purple with no improvement, about 200-400 miles. If anything it is getting worse. At this point, I dropped the Explorer at the dealership for them to evaluate...see what the outcome is as I do not have anymore time to tinker with it.

 

[Extremistno9]

I added the friction modifier to the Royal Purple with no improvement, about 200-400 miles. If anything it is getting worse. At this point, I dropped the Explorer at the dealership for them to evaluate...see what the outcome is as I do not have anymore time to tinker with it.

Final Verdict: New clutch packs needed for $950. Hopefully the whine goes away as well for that price.

 

[Green98XLT]

Interesting thread, I'm getting these same symptoms in our 02 Limited with the 3.73 LS rear... I've done the brown wire mod which disables the 4WD and I still get the "shudder" when taking off from a stop with wheels turned. I read somewhere that it could also be the viscous coupling inside the transfer case (unit that makes the full time 4WD work) I would think by disabling the 4WD via pulling fuses or brown wire mod that this couldn't be a factor but??

I have yet to change my rear diff fluid though, doubt its ever been done. I've been putting it off because I simply hate the smell of that stuff and I also have a small axle seal leak so I'm wanting to do it all at once...

 

[Joe in NY]

Interesting thread, I'm getting these same symptoms in our 02 Limited with the 3.73 LS rear... I've done the brown wire mod which disables the 4WD and I still get the "shudder" when taking off from a stop with wheels turned. I read somewhere that it could also be the viscous coupling inside the transfer case (unit that makes the full time 4WD work) I would think by disabling the 4WD via pulling fuses or brown wire mod that this couldn't be a factor but??

I have yet to change my rear diff fluid though, doubt its ever been done. I've been putting it off because I simply hate the smell of that stuff and I also have a small axle seal leak so I'm wanting to do it all at once...

Viscous Coupling is for AWD.

4WD uses electronic clutch to engage front wheels.

You can't have both at the same time.

 

[Green98XLT]

Joe, I have an 02 Limited with the 4.6 V8 and from my understanding it is technically "AWD" since you can never really turn off the 4X4 since its only options are 4x4 auto, 4x4 low and 4x4 High.

Am I correct in the fact that mine would have the viscous coupling in the Xfer case?

 

[KarinaTheDreama]

My 2002 Explorer XLT has a "shudder" when turning left or right at low speed. Feels like it's in 4WD, but it's not -- it's in "Auto". Gas mileage (highway) is holding steady at about 20.5 mpg, so I'm fairly certain I'm not "stuck" in 4WD.

This shudder only happens at low speeds, like when pulling out of a parking place. I only feel it when I'm accelerating -- once I lift my foot of the gas, the shudder stops. I feel it mainly in my hands, coming through the steering wheel, and I can hear it, too. It SEEMS to be coming from the front, but then I read here in the forums that even though it may feel like it's coming from the front, it's probably the LS rear differential. (02 4x4 Vibrating at low speed when turning, help locate technical service bulletin)

I am going test the integrity of the clutch packs as recommended in post number 5 of this thread: Limited Slip Vibration

So here's the meat of my question:

I recently (6,000 miles ago) changed my rear diff fluid and added a friction modifier. I used Mobile-1 75w-140 synthetic gear oil and a friction modifier called Trans-X Posi-Trac Limited Slip Gear Oil Additive (http://www.crcindustries.com/auto/content/prod_detail.aspx?PN=402508&S=N). Got the modifier from AutoZone. It came in a 7-oz tube. Before changing, I read that you should use only 4 oz. of friction modifier, so I didn't use the whole 7 ounces. Now I realize that Ford's XL-3 modifier comes in 4-oz. containers. So... ...maybe I should have put all 7 oz. of the Trans-X stuff in? I NEVER had this shudder problem before I changed the diff fluid. It started happening about 1000 miles ago.

So should I:

(1) Add more of the Trans-X friction modifier to the rear diff?
(2) Add Ford's friction modifier to the rear diff? (would it hurt to mix Ford's goop with the Trans-X goop?)
(3) Change rear diff fluid again and use Ford's XL-3 modifier?

Any advice much appreciated! Keeping my fingers crossed that the clutch packs aren't toast...

Thanks a million! Gotta love this forum!

Did u consider it might be AWD and needs to run e open differential? I had this one rear tire had worn crazy down and melted bushing then axle oil pressure hose blew and that. Trying to hashed out at shop dumbasses don't know think an exploder would have AWD? I'd but it's got those replaced at purchase AND I replaced the damned tranny. $2500 truck now $12k.

 

[oldgranola]

oops, ancient thread