So I got 2000 blazer ls. First I had a shake in front end (idler arm). Then everything was good for awhile. Then I noticed a small shake in rearend thought nothing of it now it got really bad. Found minor play in u joint. So I took off my driveline and since I had it off I replaced both u joints. Still around 55 mph I have a pretty good vibration in my rearend. No noise just a vibration. So I got it home checked all bolts driveline, u bolts for leaf spring, shocks, etc. as soon as I felt the vibration I figured it was tires so got new tires mounted and balanced. It almost feels like a hop... Any help would be appreciated thanks!

 

Also guy before put this rearend in cause the old one blew up. Wheel bearings make no noise and seem to be tight and no play...

 

Mine did the same thing last spring. I removed the diff cover and found chipped spider gears. No magnet in the cover meant the chips went everywhere. I wound up rebuilding the whole thing including RTV ing a magnet in the cover. Summit racing had the best price on stronger than factory parts.

 

Around how much to rebuilt it? It just had a vibration no noise in rearend after that happened?

 

$200 motive gear ring and pinion
$20 ring gear bolts


$115 Yukon spider gears "nest kit"
$150 Timken bearings and seals, gasket, shim kit, magnet and lube bought locally.

I wanted to add a $400 Detroit truetrac but it wasn't in the budget. It will be added later. Just pull the cover and give it a spin while looking very closely. Hopefully it's fine and your problem is something cheaper. Changing gear lube in a used vehicle is a good idea and you can rule it out as the cause.

 

Sounds like a tire issue.When`s the last time you had your tires re balanced?

 

Bottom of post #1. He said he got new tires mounted and balanced.

 

I picked up a 96 4dr 4x4 with 150K on it for $1300 about a year ago, i've been slowly replacing parts to get it up to mt standards, and most recently were tires.

The old tires had good tread, but were almost 10 years old and were shot. I could take the truck much over 65mph with out terrible vibrations. So I didn't, well I finally got around to changing the tires, and wow, the vibration is still there.. WTF?

Now I OWN a Hunter 9700 roadforce tire balancer and have a mounting machine as well, so i know the tires are 100% balanced and road force matched to the rims.

Still vibrates at between 65/75mph bad.

So I look at the driveshaft. OE Ujoints, none are tight, replace them anyway, vibration still exists.

I find the TSB about the vibration, and it says to deal with it... WTF again!

So I jacked it up, spun the thing 70+mph on jack stands with front end on the ground, and at the rear end it was smooth as glass... At the tailshaft of the trans, it was blurry it was vibrating so bad...

Now what do I do? I was looking at balance masters driveshaft balancer, and/or high speed drive shaft balancing. Has anyone here done either of these? HELP! I'm ordering the balance master today. If it doesn't work, I'll be trying to find a high speed balance shop. After that I'll have a low mileage (165K) 96 4dr 4x4 LT for sale... (I drive 3 hours a day at hwy speeds)