ome suspension-vibes

[96xjdj]

Hey all I have a 96xj and just installed old man emu springs and shocks. I went with the 930coils and jc2 leafs.Gained about 2" in front and 3" in rear. On acceleration at about 40mph i am getting some heavy driveline vibrations.As I am new to this any advice on what my next step should be would be appreciated.Would it be a good idea to drive it as is for awhile or could this do damage. The install went pretty well except for snapping the bolts taking off the rear shocks.Rides pretty well just disappointed in the vibes. Thanks

 

[Scott Mac]

Hey all I have a 96xj and just installed old man emu springs and shocks. I went with the 930coils and jc2 leafs.Gained about 2" in front and 3" in rear. On acceleration at about 40mph i am getting some heavy driveline vibrations.As I am new to this any advice on what my next step should be would be appreciated.Would it be a good idea to drive it as is for awhile or could this do damage. The install went pretty well except for snapping the bolts taking off the rear shocks.Rides pretty well just disappointed in the vibes. Thanks

Check your rear pinion angle. The pinion should be pointed directly to the output shaft of the t-case. This may be easly solved by adding shims to your spring packs.

 

[xj92]

Correct me if I'm wrong, but I think you only want the pinion pointing directly at the TC output shaft if you have a CV joint in your driveshaft, otherwise you want the TC output and pinion parallel, which they are stock and still should be unless you have an extended length shackle. Which means your fix would be to install an SYE and then shim it, or just install a 1/2" or 1" tc drop spacer.

 

[Drewlee77]

Is JC2 a new spring? DPG has only JC1A (3" lift, HD) and JC1B (2" lift, Medium Duty)... but Rocky Road has a "3" medium duty" listed as well (no part numbers...).

At any rate, when I put my JC1B's on - they gave me a full 3" at first, but after a month or so they settled down to around 2.5" or so. After a year and adding alot of tools and junk to the back, I'm at 2". I still have vibes, very similar to what you are describing, but they are not as bad as they were when it was at 3". Since I have yet to fix mine, I'll refrain from just telling you what everyone has told me - but I thought I'd share from my experience that your back end may settle a little in the coming weeks. If you have tools and things like that and don't need the room - throw them in the back. OME medium duty springs are pretty soft and will sag with weight. Just my thoughts... Hopefully, I will have my vibes fixed in the next week or so. Maybe then I'll have some insight...

 

[grasseater]

Drop your transfer case 1" & see how that does.

 

[96xjdj]

The jc2 is the heavy-duty spring with the over-load thank's to all who replied prolly will try the t-case drop

 

[RobertF]

When you are accelerating at 40 you are making some pretty good torque. This twists the axle, wrapping your springs up, pointing the pinion nose up. You want your pinion angle about one degree lower than your output shaft angle so they are almost equal under acceleration for no vibes. Yours is vibing under acceleration, so your pinion angle is too high to begin with, and then getting worse with torque. Dropping the transfer case will make this angle mis-match even worse. You need to measure your angles and shim the axle accordingly. Just "Oh throw a 1/2" or 1" TC drop" is not necessarly the answer, proper angles are.

 

[Scott Mac]

Correct me if I'm wrong, but I think you only want the pinion pointing directly at the TC output shaft if you have a CV joint in your driveshaft, otherwise you want the TC output and pinion parallel, which they are stock and still should be unless you have an extended length shackle. Which means your fix would be to install an SYE and then shim it, or just install a 1/2" or 1" tc drop spacer.

Your right, I stand corrected. I forgot the stock shafts didn't have a cv. The pinion should be parallel with the t-case output shaft.