Drivetrain problems, I'm at a loss

hey, the jeeps a little broke and just asking for any suggestions.... Many of you have years more experience then me with Jeeps, and I am at a loss.
I did search, but I am still at a loss
Here are the symptoms

1) Grinding/Thumping noise when under load which goes away when I let off the gas.
2) the noise gets faster/slower with accel/decel
3) grinding is worse when decel in 4wd
4) before parking it noticed a slight squeak at slow speed
5) cant tell where the noise is coming from since the uni-body transfers sound into the cabin
Now, i checked the T/C and its topped off, as is the rear dif.
Rear ds is solid, doesn't rotate or shift when in park
Front ds rotates when in park about a quarter inch side to side
No visual leaks from front/rear difs, T/C, or Tranny

ANY suggestions would be greatly appreciated
Thank you in advance,

Nick

check the u-joints in the drive shaft in N with the parking brake set grab either side of the joint at try to twish opposite directions if there is any movement it bad. do this for all u-joints including the ones in the front axle.

when you try to turn it in park the vehicle is being held by the ds so it's not gonna turn you need to chock the wheels or use the e-brake so the ds is unloaded.

Check your driveline angles if recently lifted.

I'm sorry some background is in order,
2001
LP 30 (stock)
8.25 (stock)
RE/DPG 5"+ (ACOS up front, longer shackle out back)
RE Hack/Tap with custom ds

been driving it like this on 285/75/16s since this last July (about) and have always had a problem with 4wd (seems the shifter is tempermental)
and rear drums are going (waiting to source parts for zj disc swap)

Thanks again for the replies

Nick

that happened to me and i kind of ignored it until my driveshaft fell out as i was driving (big mistake)...i believe it's your u-joints because when u accelerate it gets faster...when your at like 45+ MPH does the squeaking go away? if it does...almost sure that it's the u-joints...try greasing them...with a grease gun or somethin for a quick fix but think about replacing those u-joints in the near future

XJSkier said:

I'm sorry some background is in order,
2001
LP 30 (stock)
8.25 (stock)
RE/DPG 5"+ (ACOS up front, longer shackle out back)
RE Hack/Tap with custom ds

been driving it like this on 285/75/16s since this last July (about) and have always had a problem with 4wd (seems the shifter is tempermental)
and rear drums are going (waiting to source parts for zj disc swap)

Thanks again for the replies

Nick

Click to expand...

Could be any/all above.H-n-T didnt work on my 2000 and the LP30 driveshaft started binding up above 4.5".

Is the front driveshaft bind something that can be fixed with a new drive shaft/better angles? or should i start looking for an HP30?

Thanks
Nick

I ran my 01 with 6+ lift on 35's with the LP-30 for over a year and a half. DS did not bind. Installed a LP D-44 now with 8+ lift and 38s and it still doesn't bind.
As to the noise, check your u-joints. Don't omit the front axle u-joints either, you're spinning these all the time as well and could effect the sound on accel/decel.

Sounds like the front CJ joint is worn. Be sure to check the center ball, not just the joints in it, as the center seems to be the trouble maker pretty frequently.

The front shaft is always spinning but its not under load in 2wd, so usually doesn't mak noise expect on accel/decel when the drivetrain moves a little. Then in 4wd when there's lod, it'll make a lot of noise.

Squeaks at low speed are also a pointer to this..