Knocking / banging sound while in 4wd...

[Singe]

Ive had my m1009 stuck in my barn for months now, but as my other pickup has just been stolen I decided to crack on with the jobs, Ive just replaced the drivers side upper and lower ball joints and put new manual locking hubs in... While on a test drive today- the first one its had in a year since I bought it- whenever 4x4 high was engaged there was a loud knocking sound, it got worse as things sped up.. In 2wd (with the hubs still locked) there was nothing.. tested it back in 4x4 and it was back..

In low it didnt seem as bad but it was there. Ive checked the UJ's and none appear to have any play, but the front driveshaft from the trasfer case does seem to turn back and forth quite a bit when you twist it.

Any ideas? Is it the front diff? Parts are hard to come by in the UK so should I bite the bullet and buy a tru trac or something?

Thanks

 

[Singe]

I was in a field for this testdrive, also worth mentioning its running 35"s with a 5 or 6" lift...

 

[TexAndy]

I wonder if it's the actual front drive shaft hitting something as it turns.

 

[Singe]

well the lower ball joint does protrude very close to the universal joint, but it never did it while the hubs were locked and I was driving in 2wd- driveshafts should be turning then? Also I was in a straight line as I was giving it the boot and it was at its worst..

 

[Singe]

sorry you mean the driveshaft to the tcase... cant see what?

 

[TexAndy]

Just thinking out loud. Do you think you could record some audio while driving around and post it on youtube?

I'm not a cucv expert by any means. But I bet if you let some people hear it "in person" someone around here will have a good idea of what's going on.

 

[dmetalmiki]

Try removing the front prop shaft. (note the angle it is running at also) Check again on road. If the noise abates on the over run It will be bearings probably, keep us informed of the outcome after checks and eventual fix.

 

[Jeepsinker]

The constant velocity joint is worn out on the front driveshaft. You'll need to have it rebuilt at a driveline shop.

 

[Singe]

Thanks for the responses-
If the C.V joint is worn out is there any quick test? or do I just pull the front propshaft out? is it likley to be the lift causing the angles to be more extreme thats done it?
I will take some pics tomorrow... and a recording if possible.. It seemed to resonate in the cab which means near the transfer case is an option.. Bearing in mind ive never driven anything American before, never mind an ex us army vehicle, it feels big and numb and noisy (not to mention very beautiful)... though probably not much worse than an old landy!

 

[Singe]

After getting it out in the field today again.. its definitely the front propshaft catching on the cradle..by the second universal joint from the transfer case.. probably as it sits up on the front suspension and the angle between transfer case and diff is too great.. texandy- Im sorry you were right!! see attached pics.. how do I sort this??