By Jeff Bieler (Mrbieler) on Wednesday, July 18, 2001 - 04:22 am: Edit

Before you avert your eyes and read elsewhere, this is not a tale of woe.

Our '97SD had developed a drive line vibration/whine when you lift your foot off the gas at 70MPH. As the speed drops through 68~66, the vibration/whine occurs. The truck has an OME MD spring lift.

After chasing the usual suspects (output shafts,drive shafts,ujoints,etc) for a week, I threw my hands in the air and ran it down to LR South Bay. At least perhaps they could help find the problem and then I could come home and fix it. The service advisors down there (Greg and Jason) have always been super.

After much time racing up and down the 405 with two techs with me in truck trying to isolate the problem (we could not replicate the noise when the truck was run up on the lift), the tech and the senior tech have declared the problem is my rear dif and that it will be replaced (thank you LR for that certified warranty!). One day to order the part, one day to install. Two days of my wife bitching about the mini-van they gave us as a loaner!

Of all the issues I've seen here for drive line vibration/whine, the rear dif is not one of the suspects I have read about. Has anyone else experienced this?

Jeff

By RVR OVR (Tom) on Wednesday, July 18, 2001 - 04:36 am: Edit

Jeff -

Wow. That dealership gets strong kudos for taking you seriously and going to those lengths to find the problem.

Yours is the first case I have heard of that it was the rear diff.

Tom

By Ron on Wednesday, July 18, 2001 - 04:37 am: Edit

The question is did it solve the problem?

Ron

By Gil Stevens (Gil) on Wednesday, July 18, 2001 - 04:42 am: Edit

jeff, my rig does the same thing. 70 mph, give or take, as you back off the throttle. we did the same, replaced my rear diff, guess what? it didnt fix it. at the time I was running Bearmach HD (2 1/2")with stock trailing arms. i switched to OME HD and SafariGard bent Trailing Arms. That fixed it alot, but not completely. It was really bad before, now its ignorable, I think the real solution is a CV shaft. good luck.

By Jeff Bieler (Mrbieler) on Wednesday, July 18, 2001 - 04:42 am: Edit

Don't know yet. We're still in the mini-van. This all happened yesterday and we didn't get back from the test ride to order the part until too late (so it's on today's order). The part should arrive Thursday morning. If the truck isn't done by 4PM Thursday, I won't bother heading South to pick it up until first thing Friday morning. Too much traffic to deal with. Regardless, the freeway ride home will tell the story.

By RVR OVR (Tom) on Wednesday, July 18, 2001 - 04:57 am: Edit

If nothing else, you still get a free new diff for driving a minivan!

By Jeff Bieler (Mrbieler) on Wednesday, July 18, 2001 - 05:03 am: Edit

Yeah. It will be interesting to hear (literally) the final results. Hopefully, it will work. If not, as with Gil, I will have to look at alternatives. A shaft is not out of the question $ wise, but I'd rather see money spent elsewhere. The whine/vibration was pretty loud and disconcerting.

By Ron on Wednesday, July 18, 2001 - 05:06 am: Edit

I will bet you dollars to donuts if they replace the T-box it will go away

ROn

By RVR OVR (Tom) on Wednesday, July 18, 2001 - 05:08 am: Edit

Hopefully they try replacing everything else first. Milk this puppy for all it's worth. Maybe you can get a new DS and trans out of it while they are at it!

Tom

By Jeff Bieler (Mrbieler) on Wednesday, July 18, 2001 - 05:17 am: Edit

LR South Bay replaced the t-box when I bought it (5k miles ago). PO evidently never engaged dif-lock and the dealer dropped in a new one after unsuccessfully fiddling with the frozen mechanisms.

By Ron on Wednesday, July 18, 2001 - 05:24 am: Edit

Ok then,

I am at a loss as to the cause.

Ron

By JEEPETR on Wednesday, July 18, 2001 - 07:21 am: Edit

Okay,

I know no one is going to want to hear this, but you are likely experiencing the end float vibration in the rear drive shaft. Could the noise be described as a "Garunkking" noise? Replacing it with a CV driveshaft may or may not help (Probably not). We've talked about this in several posts. Some disagree considerably with me others slightly (I'm a Defender guy after all...), some actually believe . Try Shortening the rear trailing arm slightly via Bent arms from Rockware or similar. To try it for free and see if it helps disassemble the front mounts for the trailing arms, and swap the bushings front to rear. This will effectively shorten the arms about 3/4". If the noise goes away, well, you know how to fix it permenantly.... Just a thought, check out this address...

http://users2.ev1.net/~krmit/FourWheeling/mods/sly/RearArms/D90RearArms.html

~Scott T.
'95 D-90 (JEEPETR)
'96 Discovery (New addition to the Addiction!)

P.S. -- The Tranny in my Disco was replaced under warantee for this while still in it's original owners hands. It was equipped with an Old Man Emu HD spring kit. Didn't solve the problem (was still doing it when I bought it, still is, haven't gotten around to fixing it), and he moved onto a Toyota Land Cruiser, Lucky for me...

By Jeff Bieler (Mrbieler) on Wednesday, July 18, 2001 - 07:26 am: Edit

Garunkking reads like a deep noise. Is that what you mean?

This is a relatively high pitched whinning noise. Almost a buzz. What you'd expect to hear when something winds down, which I guess is what it's doing when you lift off the accelerator.

By RVR OVR (Tom) on Wednesday, July 18, 2001 - 07:26 am: Edit

Scott is right, the solution of shortening (or perhaps lengthening, if they are bent or something) of the rear links is a possibility. It worked for me well. I had put on the RT trailing links and used too many of the supplied spacers and took one out. Scott-- I don't think I ever thanked you for that tip, so Thanks A Bunch!

Jeff- Did you compare the angles on the rear pinion and and on the tcase output? If they are different, that is your issue. If memory serves me correctly, they should both be at 3-4 degrees according to most folks, although mine seemed to both be at about 2 when all was said and done. They match though, and that is what's important.

Tom

By Jeff Bieler (Mrbieler) on Wednesday, July 18, 2001 - 07:31 am: Edit

Did not look at the rear angle. When I did the lift, the front angle was the primary concern.

I'm surprised the concern (if it's not the dif that's bad) is in the rear and not the front. The OME MD lift is pretty mild.

By Steve (Steve2) on Wednesday, July 18, 2001 - 07:45 am: Edit

hey jeff

i had excessive clunk when shifting from d to r or r to d. so l/r thousand oaks replaced the front diff. now the car drives way smoother than before and feels more 'perky'. also the klunk from r to d is gone. the d to r is still there. not sure if this will help you or not - but just wanted to tell you how much smoother the car was.

see ya
steve

By Jeff Bieler (Mrbieler) on Monday, July 23, 2001 - 12:41 pm: Edit

Well, the Rover is back. It was due back on Thursday night/Friday morning, but the tech who was doing the work did not complete it by Thursday and had Friday off. Rather then have someone else finish the job and do the post-diagnostic, we decided it was better to let the same guy finish the job as he knew what to listen for as he went on the test rides with me in the first place. Besides, it gave me the whole weekend to harass my wife about driving the mini-van they lent us.

LR South Bay replaced the rear dif. Final cost to me was the $100 deductable. The truck drives fine, does not vibrate or make noise, and actually seems a bit smoother now.

Hopefully, this will be the final chapter on this problem.

By John on Monday, July 23, 2001 - 12:45 pm: Edit

Cool, glad you are up and wheeling