700r4,4x4,auto,91 model.

Clunks when you put it in drive or reverse. Shifts fine etc. just clunks when changing. Its done it for a while. Im just wanting to fix it now. I was guessing a u-joint?

 

Sounds like u-joints to me.....crawl under and check them.

 

x 2 on the u joints

 

I need to replace them anyways...but darn gm...i dont have a way of heating them up to get em out....there goes 60 bucks for a hour labor down the drain,plus cost of ujoints.

 

When i put it in park or drive,or reverse it clunks.. I just came in from replacing both u joints. Still does it. Got back under it and tried turning on the driveshaft and it turns about 3/4 to a inch then i hear that clunk...So...im guessing its the rear end. Any input before i head down to the junk yard and spend another 200.00 on this Pos(i love my blazer dont get me wrong,but this thing is starting to **** me off lol)

 

Turning it 3/4" is a TON! have you tried taking out a u-joint & trying to turn it? That way you'll know if it's in the trans or in the rear by the process of elimination. Just a thought that I'd use to narrow it down. No sense tossing bad money after good.

Just re-read that - it does it in park?! You're stopped, put it in park & it clunks? That sounds like trans, sorry to say, take the easier u-joint out & see if it still does that 3/4" turn. Lets say you take out the rear u-joint & the driveshaft is only attached to the trans & it turns - voila, you know it's in the trans.

 

It does it when you shift from park into drive or reverse,doesnt do it when you shift back in park. I'll pull the driveshaft out again and see which one turns. I think its the diff come to think of it. Friend was reinstalling shaft while i was out from underneath it. He couldnt get the shaft aligned properly against the diff pinion yoke until he told me to put it in neutral so he could do it. and with a 3/4 turn,im sure he could of got it lined up if it was the trans that was slacking..I guess its a good time to bump up the ratio to 3.73 with a axle from a bravada. there is a bunch of em down at the pull it yard.


Just out of curiousity. Ive never been in a axle before. I know what the yoke,ring, and pinion is,. could this be a bearing/"spacers" issue ive heard about that could be fixed without pulling the rear diff?

 

How much back lash is there at the rear axle? at the transfer case output? 3/4 of a turn at the rear axle is just not possible without a stripped ring and/or pinion gear and if that were the case, you would have a whole host of other signs pointing to that as the problem. Even 3/4" of rotation as referenced at the OD of the driveshaft sounds excessive and shouldn't be possible without the rear end making quite a bit of noise.

 

Hmm. well i never hear a noise while driving etc. I feel it when it goes into gear,or if i slam on the gas for a sec then off again..Im just going to go until it pops then put another one in i guess.