Transfer case mount and bushing allowable play

I have an 86 3/4 ton 4x4 that vibrates when you reach 55 mph. I have replaced the u joints (there are just 2 on the rear shaft) which did quiet it down some.... but the vibration/drone remain. I have noticed that when I push up on the drive shaft near the xfer case the mount below the xfer case allows the two to raise close to an inch. So I am curious to know if anyone can advise me to approx how much play there s/b in the xfer case mount as well as the xfer case bushing. I believe it is the "208 C". Seems the rubber mount would get harder over time and be less forgiving.

Thanks,

MS

Reply to
siveman
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Zero play in the mount using the technique you posted. (unless your a competive power lifter..then negate the above)

Zero play in the X-Case bushing...with extremely slight movement as a DIY'r gauge for tolerance.

~:~ MarshMonster ~wonders why you have'nt mentioned all that tranny fluid that's everywhere under there........oh well, another post~

Reply to
Marsh Monster

Today I took a ratchet strap and wrapped it around the xfer case and then cinched it up. This pretty much eliminated any up and down movement. I then drove it and the vibration starts around 57 mph and levels out around 65 and then intensifies again as you go past 65. It may be time to have another mechanic look at it. I have noticed that the little bit of fluid coming out of the xfer case (dexron II) is brown. When I first bought this truck I had to add 1 1/2 qts of fluid to the xfer case and 2 qts to the tranny. Makes me wonder about the integrity of the xfer case. The tranny fluid is a good red color w/no burnt smell to it. It is a good truck for into town and back. But I would like to be able to drive it to the nearest Menards or Home Depot (4

1/2 hour trip) w/no worries.

MS

Reply to
siveman via CarKB.com

Remove rear driveshaft and have it balanced and your problem will go away. It is not unusual for them to go out of balance from usage and the elements eating away at them.

----------------- The SnoMan

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Reply to
SnoMan

Ya know... I replaced the u joints at both ends. While doing this I noticed quite a bit of debree making noise on the inside of the shaft. I suppose over the years it flaked off of the inside and settled at the low end of the shaft. Ever hear of this causing trouble, thus making the shaft off balance?

MS

Reply to
siveman via CarKB.com

I have owned several GM trucks and none of them had a drive shaft that was really properly balanced and some are worse than others. When my

89 burb was new the drive shaft was out of balance and I paided to balance it because dealer said it was acceptable.

----------------- The SnoMan

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Reply to
SnoMan

Hey SnoMan, just curious about how much did this run you? I think my

89 1ton has the same issue, gotta get this done, any recommendations on best shop to do this? Specialty or any old one?

Thanks

Reply to
89GMC

The problem was fixed by replacing the yoke on the rear axle. The tabs that keep the u-joint centered had spread.

Thanks again,

MS

Reply to
siveman via CarKB.com

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