[Kor3y101]

Hello,

So after breaking the short side transfer mount, I ordered 3 new ones from suzistore and they arrived.
Being lazy, I only replaced the broken one and kept the others as spares. The ones that were on the Sierra when I first bought it were round ones. I have now replaced them with square ones.

So the story goes, I replaced the broken one on the short side and drove it for a couple weeks without any issues. On New Years Day I went up to Queen Mary Falls and as I was driving up the mountain and around a corner I saw the stick start to shake side to side like it had a broken mount.

So a few days later I changed the long side mounts to the new ones. However the problem persisted. Ordered a transfer bush kit, I've installed that today and still no change. Shakes just as bad. I drove it without anything covering the tunnel so I could see the case, and the whole thing shakes, not just the lever.

It does this when taking off in first and when giving it a boot full after just changing to second. Any other gear is normal.

I have checked the mounting bolts are tight on the case and the mounts and they are all good.
I've checked the Uni joints and they seem to have a slight amount of movement, but it's hard to tell if it's the joint or just the shaft moving around. It moves sideways maybe 1-2mm at most.

I'm at a lost as to what it could be. Is it possible the mounts are too soft and allows to much movement? Or is it something else?

[Kor3y101]

Here is a video of me grabbing the rear tail shaft just before the joint in the first 1/4 of it (no idea what else to call it) and shaking it.
It seems to shake far too much for me to be happy with it I think. Which is what makes me think something is wrong with the mounts.

Here's a video of it;
http://s1383.photobucket.com/user/Kor3y ... w.mp4.html

[just_cruizin]

Jack shaft Uni joints is my bet

[Kor3y101]

So that would Let the case shake around like that? I'll double check the joints in the morning.

[Gwagensteve]

Unis.

There should be no detectable play in a Uni in any direction.

[MrRocky]

Ive found all aftermarket replacements including lowrange to have a stupid amount of movement when compared to stock.
Just cruzins poly kit seemed good

[jdk81]

+1 on aftermarket unis, they suck butthole.

I pillaged old oem from other shafts, and fixed the issue. 20 year old unis work better than aftermarket ones.
I would only buy oem unis

[MrRocky]

I meant tcase mount

[Gwagensteve]

I like stock Bridgestone mounts in 1.3's. They're vital in taking shock load off the transfer gears.

Steve.

[greenzook89]

I got Koyos last time... seem to be holding up well so far.

EDIT: koyo unis. I'm still running stock oem rubber mounts and have a spare few from a lowkm Jimny for spares.

[Kor3y101]

I've ordered a pair of new ones today, hopefully get them in a couple days and throw them in the jack shaft to see if it fixes the issue. I got under this morning and tried to see if there was much play in them, the joint that bolts to the transfer case has a bit of sideways movement from the shaft, probably 2-3mm. I suspect the gearbox end would have the same.

So I hope that would be causing my issue.

[Gwagensteve]

That's going to be it. The vibration will cause rapid failure and when the Uni goes it's not uncommon to destroy a yoke. Annoyingly when it's the jackshaft, that's often the slip yoke in the back of the gearbox.

[MrRocky]

U can also have similar vibration with a tight uni, it can have no play and seem ok but be almost seized.

[Gwagensteve]

Good point Mr Rocky. Much harder to detect.

[Kor3y101]

Yeah, either one may be it. But it definitely seems to be the U-joints. So I'll get them fixed as soon as possible.
Also Steve, when you mean when a Uni goes it destroys a yoke, do you mean when it decided to go bang and snap, or at its stage now?

Cheers,
Korey