You fit a lift, drive away, and there is a new vibration through the floor that was not there before. This is one of the most common complaints after lifting a Jeep, and the cause is usually the driveshaft angles and not the lift kit itself.
This guide explains what changes, how the problem shows up on the Cherokee XJ, Wrangler TJ and Wrangler JK, and the usual fixes. It is general guidance and not a substitute for inspecting your own vehicle.
Why a lift causes vibration
Lifting the body away from the axles makes the driveshafts run at a steeper angle. Universal joints and CV joints are designed to work within a limited range of angles. Push them past it and they stop running smoothly, which you feel as a vibration, and they wear much faster.
Is it the driveline or the wheels?
- Driveline vibration is usually felt through the floor and seat, changes with whether you are accelerating or coasting, and often appears in a particular speed band.
- Wheel and tyre vibration is usually felt through the steering wheel and depends on road speed only. Have the wheels balanced first if you fitted bigger tyres at the same time as the lift.
A violent shake of the front end set off by a bump is a different problem. See our guide to Jeep death wobble.
Cherokee XJ and Wrangler TJ
On the XJ and TJ the vibration is usually in the rear driveshaft. The TJ's rear shaft is very short, so even a modest lift makes a big change to its angle. The factory slip yoke on the back of the transfer case also has less engagement once the axle sits further away.
The common fixes, from least to most involved:
- Transfer case drop. Spacers lower the transfer case to reduce the angle. It is cheap and works on smaller lifts, at the cost of ground clearance.
- Pinion angle correction. Shims or adjustable control arms rotate the rear axle so the joints run at matching angles.
- Slip yoke eliminator and CV driveshaft. The long-term fix on taller lifts. A slip yoke eliminator shortens the transfer case output and a double cardan (CV) driveshaft copes with the steeper angle. The pinion is then set to point at the transfer case output.
If your Jeep already has a double cardan driveshaft and the vibration has come on with age, the joints or centring yoke may simply be worn. We stock a Spicer 1310 CV driveshaft rebuild kit with greaseable universal joints for the TJ, XJ and ZJ, and the Spicer 211544X socket yoke assembly.
Wrangler JK
On the JK the weak point is usually the front driveshaft. The factory shaft uses a Rzeppa CV joint at the transfer case end, protected by a rubber boot. At lift heights of around 3 inches or more, the joint runs at an angle that can tear the boot. Once the boot fails the grease is thrown out, dirt gets in and the joint wears quickly.
Check the boot for splits and for grease flung onto the underbody around the transfer case. If the joint has failed, we stock a high-angle Rzeppa CV joint kit as a factory replacement for the JK.
Before you buy parts
- Check every universal joint for play and for rust-coloured dust around the caps, which means the joint is running dry.
- Check CV boots for tears and missing clamps.
- Make sure the driveshaft has not lost a balance weight.
- Note your lift height and whether the vibration is under power, on the overrun or both. It helps narrow down which shaft is at fault.
Not sure what your Jeep needs?
Send us your rego or VIN with your lift height and what you are feeling, or call 0421 163 823, and we'll help you work out the right parts.