bossenator

My jeep get a nice vibration under my feet only in first under hard acceleration or when I'm under load. You can put it in drive hold the brake and give it has and duplicate the vibe, any ideas, changed motor mount and seemed to get a lil worse

TwoXJS

So, if I read correctly, you have a 3.5" lift on it? Did you get a Slip Yoke Eliminator kit, or a Transfer case drop kit? It's possible it's the driveshaft angles if you don't have either kit installed. I have a 3" lift, but the rear has settled enough to seemingly get my angles okay and I've removed my T-Case drop (reasons other than lack of need).

If you have one of those kits on it, then I'd be looking at your U-Joints, or maybe even your brakes since you said you can duplicate it by holding them. Also, since you don't have to worry about the T-Case leaking fluid like I would, you can pull your rear driveshaft out, put it in 4-Hi and drive it like that to see if it's still there. Don't try and turn with 4x4 engaged, unless you've got an NP242, in which case you can use 4-Full Time.

freegdr

Exhaust hitting floor/cross member area.

DFlintstone

I think maybe twoXJ missed that you are not moven! Tranny mount, the other engine mount? Maybe see if you can see the engine move when you power-brake it, check that the exhaust is not touching anywhere.

TwoXJS

Oops, sorry, I did miss that! After DF mentioned that, I'm on board thinking it's the exhaust hitting the crossmember. I'm pretty sure mine's doing that, too. Fairly harsh and loud vibration around 2000RPM, standing or moving.

DFlintstone

Well, you get points for being thorough! (And yes, I've done about that also). Heck, the info is there forever, someone will benefit from it someday.

freegdr

Huh ?

freegdr

Whose Df ?

SteveMongr

It's OK to turn circles if you wish in front wheel drive 4-Part time.
4-Full Time (242) without a rear drive shaft and the Jeep will not move due to the center differential.

TwoXJS

Oh....Well, i did not realize that! I always though turning in part time, regardless of the rear shaft being removed was bad. Learn more everyday! Thank you for that, by the way!

And Freegdr, I was reffering to DFlintstone. I was tired last night on break at work, too. Just tryin' to help out as much as I can!

Turbo X_J

Have you performed a compression or fuel pressure test?

freegdr

Ok thought there was a ghost post ....lol...

bossenator

So I think I found the trouble spot. The flange where my exhaust connects to the exhaust manifold is about maybe an inch from the bottom of the tranny where it connects to the motor, would getting new tranny mounts possibly raise it up an inch or so? Just replaced both motor mounts so I figure i woul do the tranny mounts next. Or would new mounts just raise the tranny having the exhaust attached to the motor it would raise the same?

bossenator

Bam!! Fixed it!! In case anybody was wondering I replaced al shocks and motor mounts still the same but ride was night and day better. Replaced the tranny mount and bam!! Vibration gone!!