front driveshaft vibration issues

[JBE]

Hi All

I'm not sure if it's just my truck or if this is a common problem:

I have a LWB GQ with a 5" lift. A while ago, the front driveshaft got swapped when the diffs were re geared. We choose to use the driveshaft out of a RB30 (smaller flanges) because we didn't want to swap the flanges at the diff centres.

The castor at the front diff is 2deg (i.e. within factory specs) which should equalise the uni angles on both ends.

Ever since, I had a front shaft vibration (hubs engaged) from about 70 km/h onwards. I checked the driveshaft and cant find anything wrong with it. I can't remember having had this problem with my old driveshaft before the regearing job.

Now, what I want to work out is:

- is this a common problem which I have to live with
- could the drive shaft be stuffed and is there an easy way to work this out

Cheers
Joachim

[-ET 4wd-]

check the slip joint, and the uni's
Also can the 3ltr shaft be pulled apart?
If it can make sure the 'welded' ends of the shaft line up, had the same prob with my 45 all i had to do was pull the slip jointout and rotate it 45 degrees

Hope this helps,

Steve.

[JBE]

I had the shaft out. Slip joint and unis seem to be ok. That's what puzzles me.

Cheers
J

[weeksy]

Castor is one thing.

But what kind of angles are the uni's runing at?

[Nelso]

Mines the same. With factory caster and 5" lift your unis are at different angles so the driveshaft is out of dynamic balance. If you are going over 70km/hr unlock your hubs and do it in 2wd.

[Jimbo]

I have a 4" lift and it starts to vibrates around 60km/hr. I might put some more grease in teh slip joint.