BJ42 Highway Vibration (1 Viewer)

Joined
Feb 2, 2014
Messages
276
Location
Vancouver Island
Hey all,
I've got my 83 BJ42 on the road at long last and things are looking sharp, however I've got a vibration at highway speeds and am looking for other thoughts on places to look. I've been working on this project a while and feel saturated- would be good to have other insights.

Here are the details on the vibration:
- Driveline vibration only and shows up in the shifter stick at about 85km/h (it shakes side to side, not a hum)
- NO vibration felt in the steering wheel
- Feels like low speed/rotational. Wheels are balanced (twice) tires are new.
- Gets worse the faster I go, but stops completely below 85ish km/h

Specs on truck:
OME lift, new bushings, anti inversion shackles.
rebuilt drive shafts, uni joints
new engine and trans mounts
rebuilt diffs, trans, transfercase

Truck does have a tape measure alignment done, but that should be good enough.
Front shackles are on backwards.

The driveshaft angles look ok and I'm used to ujoint phase issues being more of a humming vibration than a wobble like i'm feeling in the stick. I wouldn't rule that out completely though as I've had the rear shaft in and out a few times while working on the truck. I've thought to perhaps remove the shaft and have it balance checked and confirm nothing is amiss.

Anyone else experience this or have any secret spots to check?
 

jim land

SILVER Star
Joined
Aug 6, 2007
Messages
1,927
Location
scott quebec
I have the same set up on my 84 bj42
Im using a 4 degree steel shims on the rear to get the pinion kind of level , it need to be parallel to the t-case output , rear shaft is very short with the h55
It still vibrate from 90km + , but on my case its probably the new 33x10.5 on stock 5.5" wheels , the shop who mount them got hard time balancing one tire , i will try an other shop to check balancing and or use airsoft bb
 
Joined
Feb 2, 2014
Messages
276
Location
Vancouver Island
I have the same set up on my 84 bj42
Im using a 4 degree steel shims on the rear to get the pinion kind of level , it need to be parallel to the t-case output , rear shaft is very short with the h55
It still vibrate from 90km + , but on my case its probably the new 33x10.5 on stock 5.5" wheels , the shop who mount them got hard time balancing one tire , i will try an other shop to check balancing and or use airsoft bb

I'll definitely check tcase output and pinion angle.. Good thought. I've only got 31x10.5 but also on the stock 5.5 wheels.
 
Joined
Mar 3, 2012
Messages
547
Location
Indiana
If your shackles are longer than stock then you would benefit from degree shims. Aluminum shims squish and your u bolts won’t stay tight. Need to find steel shims.
 
Joined
Dec 13, 2012
Messages
1,265
Location
KY
You said you rebuilt the driveshafts, when reassembled were they clocked correctly?

driveshaft01.jpg


This will explain it better than I can. I know the drawing doesn't show the slip joint but if incorrect it's as simple as sliding the slip joint apart, rotating to the correct orientation and then slipping back together.
 

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