Lift install with slight issue...

1992 xj, 4.0l, aw4, np231, d35

installed a spacer/bastard pack 2" lift over the weekend. everything went great, and the ride is awesome.

When I enter steep driveway's though, I get a rotational thump-thump that is rythmic and eventually goes away.

Intermittant, suble, quiet sound.

I'm thinking possibly rear driveshaft ujoints, possibly slip yoke needing to be swapped for a longer unit.

I'd love to fix it with a tcase drop kit for $20.00, cuz I'm swapping in a 8.25 soon, and don't want to spend any money on d35 axle/driveshaft stuff.

here's an existing question and answer on the portal:
http://www.expeditionportal.com/forum/showthread.php?t=42640


Anyone have any insight? I lubed my joints, and checked torque on my bolts. I've ruled out exhaust, and doubt its the front end, though I could be wrong.

noise is made mostly around 5-10mph, going straight, usually after getting on or off the throttle. Slip joint is only about 1/2 - 3/4 displaced from usual position..enough to cause some binding?

Or just old, dry ujoints?:explosion

thanks in advance..

Brian

what i like to do sometimes is have someone else slowly drive the car while i walk beside it and try to pinpoint the source. at least find the area producing noice. this will keep you from just throwing money at the car.

broken bands in the tires could give you a thump too. ask me how i know. hit any pot holes recently? ya never know... could be the simple things. though mine broke from going end-o over a jump.

Drop your rear drive shaft and visually check your u-joint's. (pull the caps)
When I did my BB I had bad joints and never knew it till after the BB was installed.
Got a vibe and a clunk.
The rear joint was wore so bad that the part that the bearings ride on was half wore off on one end.

ok, I'll check each of those things. Thanks, you guys.

any other suggestions are welcome!

cheers!
Brian

i have the RE t-case drop spacers if you want them. youd just need the bolts.

1990JEEPXJ said:

i have the RE t-case drop spacers if you want them. youd just need the bolts.

Click to expand...

Yeah, i think ill take em.

I'd put money on pinion angle because the driveshaft is vibrating. You can drop the t-case or go SYE.

xjs should be good to about 3.5 till they need a sye or drop. i think it may be something else/

Have you "clearanced" the drive shaft yokes yet? Might be the source of your noise.

May sound stupid, but you said it happens going into steep driveways, so it makes me question if your tire is rubbing on your fender flare. With the wheel turned at the right angle and the suspension compressed from going up the driveway it might hit, even though it doesn't look like it would on flat ground. My tires catch just the edge of my flares when the wheel is turned and I drop off my curb in reverse hard. Mine isnt quiet or subtle though, the knobs on my tires make it a pretty loud rotational thumping.
Just a thought. Sometimes it really is that simple though.
Lightfoot

Weaselton said:

Have you "clearanced" the drive shaft yokes yet? Might be the source of your noise.

Click to expand...

Gosh, you know, with such a small lift i didn't even consider it. But certainly i'd entertain the thought they are hitting. Im a pipe-hittin' mofo when it comes to grinding.

I did check for wear marks, shiny metal, etc when i was lubing everything and didn't see anything "abby-normal" (young frankenstein reference. I'm a dork..)

2 inch lift wouldnt need an sye or a drop. Rulling that out check all of your joints.

Lightfoot said:

May sound stupid, but you said it happens going into steep driveways, so it makes me question if your tire is rubbing on your fender flare. With the wheel turned at the right angle and the suspension compressed from going up the driveway it might hit, even though it doesn't look like it would on flat ground. My tires catch just the edge of my flares when the wheel is turned and I drop off my curb in reverse hard. Mine isnt quiet or subtle though, the knobs on my tires make it a pretty loud rotational thumping.
Just a thought. Sometimes it really is that simple though.
Lightfoot

Click to expand...

No, totally good thought. This happens when im driving flat and straight after a driveway, though, not during. Very weird! Didn't hear it/feel it at all today. No driveways though. Just my 20mile commute.

Check your tranny mount.

homebrew said:

2 inch lift wouldnt need an sye or a drop. Rulling that out check all of your joints.

Click to expand...

Yeah thats what im leaning towards, paul. I'll probably throw a drop on anyways just cuz one is being karma'd to me, and to bring the slip joint back into spec. (this is my daily driver/ mall crawler/ overland rig not a rockrig, so i dont care about a lost inch )