jackshaft diagnosis

Post by **rogerramjet** » Mon Dec 10, 2007 6:09 pm

Hi All

I have a vibration problem in my 1991 suzuki sierra. The vibration is there in two wheel drive, four wheel drive and in front wheel drive (with tail shaft removed). Vibration continues with clutch in and gear in neutral.

That means problem is in gearbox output shaft, jackshaft or transfer case. Is that correct? Most likely would be jackshaft?

Jackshaft looks fine and so do UV joints, although when I turn jackshaft by hand the transfer case moves side to side slightly and there seems to be a slight hard spot each revolution of the jackshaft. Does this isolate problem to jackshaft or could there be something wrong in transfer case or gearbox?

Thanks in advance

Roger

Post by **alien** » Mon Dec 10, 2007 6:31 pm

check you dont have mud in your rims first =) i fell for that once.. hahaha

Post by **ScrawnC** » Tue Dec 11, 2007 1:10 pm

Remove jackshaft completely and check for free movement of uj's through full range of movement. You may have a seized uj. If not jackshaft check other two as well.

Post by **v840** » Tue Dec 11, 2007 2:38 pm

Also check your tcase mounts.

Post by **Bajan Tim** » Wed Dec 12, 2007 1:44 am

had this exact problem recently.....
it turned out that one of the unis was ceased on one axis....
only realised it when i decided to check it a second time an took it out completely, replaced both with some greasable ones

Post by **rogerramjet** » Fri Dec 14, 2007 6:37 pm

Well it was exactly like Bajan Tim, one axis on a uni is ceased.

What is the best way to fix? Complete new jackshaft or get someone to rebuild unis? I would imagine the jackshaft would have to come from suzuki which would be expensive would it? Although I don't know if its worth fixing an old shaft and whether theres additional costs like rebalancing and alignment issues?

Post by **Bajan Tim** » Fri Dec 14, 2007 9:36 pm

I had my unis replaced with some greasable ones

Post by **zookimal** » Sat Dec 15, 2007 12:06 am

Just pull the jackshaft out and put a new uni in the transfer end. If that's all the problem is it's a cheap fix.

Post by **v840** » Sat Dec 15, 2007 9:05 am

Replace both unis on the jackshaft, it saves having to pull it out when it happens to the other one. They've both done the same amount of revolutions so its probably nearing its used by date anyway.

Post by **rogerramjet** » Sat Dec 15, 2007 2:42 pm

cheers fellas

Does anyone know if there will be a problem if I put the bolts the other way round when I re-fit the shaft? It is better that way because you can access the nuts with a socket (or an impact socket as they were really hard to get off).

Post by **NIK** » Sat Dec 15, 2007 5:47 pm

Either way should be fine but I can only get mine in one way so thats the way they are staying 2 12mm spanners to do up.
Nik

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