I did my best to search for better descriptions of the symptoms related to the clutch packs, but my impatience got the best of me.

Anyway, my ’04 FX4 has been starting to “slip” I guess is the best way to describe it, when I slowly accelerate after making right turns mostly. It’s like the truck can’t find traction, but is on dry pavement. Once in a while when going up a hill or incline, the same thing occurs. Always seems to be when at part-throttle or slow acceleration. It does not seem to be the transmission, but who knows since I still can’t get used to the electronic catch-up it does at part throttle.

Is there anything I can do to diagnose the clutch packs? Or other specific symptoms I should look for? Besides an obvious trip to the dealership, which I would like to save for the repair if needed, since I like having a general understanding of what is going on with my truck prior to taking it in. Not that they would take advantage, but…

Thank you in advance for any and all information you can provide.

 

How many miles on the truck? One cheap thing to try is change the flluid in the diff to the new recommendation (75w140 instead of 75w90), add the friction modifier and see if the problem goes away.

 

If you feel the "slip" while going slow and making your turn it's probably the clutch in the LS,, i also have a 2004 and mine did the same thing. Was a common problem with the 04,, took it in to dealer under warranty and he did not hesitate,,replaced the clutch pack, that was 3 yrs ago,, problem gone.. good luck.

 

That is why I suggested the fluid change. Had the problem on my 04. My dealer tried a fluid and modifier change at 20k. Went to 70k when I traded it with no problems. As this one will be his dollar unless still under extended warranty, that is a cheap try over replacing a clutch pack that may not be bad. Also by opening the diff, he will be able to see if there is clutch material in the fluid and know if he needs a clutch pack.

 

I have just turned 35,000 miles on it, and am getting ready for an oil change anyway I may try the fluid change. Sounds like the cheapest thing anyway. Anything I should look for while making the change of fluid? Discoloration or something like that?

The strange thing, is that it doesn't do it all the time, but who knows.

 

Thanks for the replies by the way! Also from the factory we're running synthetic fluid in the rear diff, right? I will replace with synthetic and friction additive anyway, but wanted to be sure.

 

Yes it is synthetic. What came from the factory was 75W90, get the 75W140 to replace. Look for suspended particles (clutch material) in the fluid. Or pieces, or metal.

 

I had the same thing happen to my 04. Changed the fluid and the problem was gone.

 

Thanks, I hope that a fluid change is what is needed.
I will dread finding any of the clutch or metal particle floaters when I drain the rear... Then I guess I will take my old fluid with me to the dealer for the replacement/repair of the clutch packs.

Thanks again for all the info!

 

same thing happened to mine, took it to the dealer they replaced the clutch pack an the limited slip, i guess i wasted the whole thing from pulling a 28' enclosed trailer on a snowmobile trip,every time i'd turn a corner pulling it , it would slam an bang,but it made it back home ,but tore it up pretty good.