Hi Guys,

It's been a long, long time since I've posted here and I don't really know most of you folks at all. I have a 2001--I'm the original owner. Recently, she starting making some grinding noises in the rear end at low speeds, especially when turning. I have had a chance to get under there, but I'm guessing it's the differential--a carrier bearing or something.

I'm in Austin, TX. I doubt I'll have the time or expertise to really fix this issue once I've isolated it a bit more. Any recommendations on where to take it? I hate to pay the price for taking it to the dealership...I can imagine what they'll charge for replacing the diff...

Thx for any input.
--Rip

 

Are you getting any gear whine and certain speeds on acceleration of decel? Could be the backlash on the ring and pinion. Also could be the clutch packs in the LS. You could try to service the rear and use Lucas to quite it down(really works). You can also put it on jack stands and try to pin point the noise location with a helper. GL

 

Thanks for the feedback.

I should have mentioned, it definitely slips/shutters. Most notably at low speeds you can feel the tires spin (coming from a stop) and occasionally at highway speeds.

With a helper, driving just forward and backward on my little dead end street, it clearly sounds like it's coming from the pumpkin or near by. This weekend I need to get closer to it, but it's getting worse quickly, so I figure we're near the end...

I'll pop it up on jack stands tomorrow. Any other suggestions on what to look for?

Thanks for your input.

Rip

 

You did not say how many miles are on the truck and what, if any modifications, especially drive train.

I am assuming that it is high mileage with minimum mods. In that case, you could try changing the oil including the modifier oil. In some cases this will clear it up for a while. There is a tag on the rear pumpkin under one of the cover bolts that tells you what weight and type of oil that was in at factory build time.

Most likely the clutch packs are gone and will need to be replaced. Unless you have the knowledge and the tools, this is not a job to be done easily. The other item is that the carrier bearings, ring and pinion, pinion bearing, and seals will be worn as well, basically a rear end re-build. A lot of lightning guys, me included, have switched to a Detroit Tru-Trac, no more clutch packs and one wheel burnouts.

I would not recommend adding any non-synthetic oil to it, just masking a problem that will really bite you in the future.

 

Not many miles--less than 50K. She's mostly a garage queen. Not any significant drivetrain mods.

What's the best way to determine whether it is a ring and pinion/carrier bearing issue or clutch pack problem? If it's the latter, a Detroit Tru-Trac has been one of those "when it breaks, I'll improve on it when it needs to be fixed" mods that I'll probably jump on. From what I can tell, it can be a DIY project, even if one's not particularly knowledgeable about the rear end, right? (I can figure most things out with time...)

Thanks again for the inputs, fellas.

 

You didn't say it was almost new, It would be unusual to have the clutch packs be bad with so few miles,unless it is driven hard. I would just do an oil change and be sure to add the friction modifier made by ford.

These clutch packs tend to be noisy on sharp corners and when changing direction, like backing up then going forward etc.

If you want to do it yourself, be sure to have the right tools and do some research ,

a couple of links http://www.drivetrainspecialists.com...ford/ford-975/

http://www.accuautoparts.com/index.jsp


The second one has do-it-yourself help tutorial materials.

Good luck, let us know what you find.

 

Thanks. I wasn't able to get to it yesterday, but if the rain gives up today, I'll take a look. Will keep you informed...