Spring lift at rear causing noise/vibration?

M

Mike1

New member
Hi

I have a 98 Cherokee(XJ). I recently fitted some load hog helper springs. This increased the lift on the rear to a large degree. If you look at the vehicle side on you can see the roof line sloping from back to front, as the rear is obviously allot higher.

The result was more stability but huge wining and droning noises throughout the cab.

What can be done to remedy the situation and why do these noises happen?

Mike (SA) :?
 

i hope you put in longer shocks too, if a lift was the intention? how much was it lifted? most helpers will lift about 2", should not be enough to cause a vibration unless it was already lifted.... you may have other issues.
 
It's due to the increased driveline angle. You should be able to correct it by dropping the transfer case 1/2" using spacers. It doesn't take much on the 97 and newer XJ's to cause vibes.
 
Hi Twisted Copper

I would asume that everyone going for a bit of lift would then need to drop the transfer case? Would this mean that the autobox has to be dropped as well?

Over how many inches of lift roughly would you start to get vibrations/noise, in your experience?

Mike
 

I have no experience lifting an XJ yet (other jeeps but not an XJ), but I'm getting ready to lift mine and have been doing some serious digging/research and everything I read says that the '97 and newer XJ's are very prone to vibration at any lift height. Especially when equipped with the Crysler 8.25 rear axle (different pinion angle??). If you got 2" of lift, from what I've read you should drop the transfer case 1/2".

This is done by adding 1/2 spacers between the transfer case skid plate and the frame at the 4 bolt locations at the 2 sides underneath the transfer case. Keep in mind the skidplate is what supports the transfer case so make sure you support it safely with a jack while doing this.

There are lots of kits for sale but I doubt you'll find one that is only 1/2". Most are for larger lifts.

Don't take my word for it, do a search on the topic as there are may forums and tech articles where it is discussed.
 
Hi,

Realize that using a transfer case drop kit is simply a spacer which goes betwwen the frame and the transmission/t.case cross member to lower the drivetrain in the rear. This is both the cheap and (in my opinion) the worst way to go about fixing any vibration issues.

A better (but more expensive) option is to have a Slip Yoke eliminator (SYE) kit installed on the transfer case and a CV style drive shaft put in place of the exsisting one. This is pretty expensive, though.

Other options which may have to be used are shims under the rear leaf springs to help with the differential angle in relation to the driveshaft, and having your existing driveshaft modified. :mrgreen:

-Nick :!:
 
A '98 will need the driveline adjusted when 'any' amount of lift is added. The best for many is a .5" transfer case drop. I made mine from a 2"x10"x.5" piece of metal bar. Cut it in half and lay the transmission crossmember over it to mark the drill holes in the metal bar. Then remove the crossmember stud from each side and reattach the crossmember, spacers, and .5" longer crossmember bolts.

A SYE and CV driveshaft is not for everybody. It's expensive and often unnecessary for shorter lifts and/or those that don't frequently wheel.
 

XJNick said:
Hi,

Realize that using a transfer case drop kit is simply a spacer which goes betwwen the frame and the transmission/t.case cross member to lower the drivetrain in the rear. This is both the cheap and (in my opinion) the worst way to go about fixing any vibration issues.

A better (but more expensive) option is to have a Slip Yoke eliminator (SYE) kit installed on the transfer case and a CV style drive shaft put in place of the exsisting one. This is pretty expensive, though.
Click to expand...

I would agree about the SYE, but we're talking about a helper spring's added lift height here, not a 4" suspension lift :shock: I don't see how a 1/2" drop to the xfer case could be the "worst" way to go. Cheap, absolutley! That's the part that makes the most sense. Shims are hit or miss, they may or may not help.
 
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