1982CorvetteDude

I noticed that I had a thump when I put it into drive....I'm assuming it's the driveshaft U-Joints.

rear wheels are up off the ground.....

I crawled under the car and it feels somewhat tight...a little play in the shaft, but nothing major.

The half shafts are def tight....no play or movement.

I'm going to go ahead and replace the driveshaft u-joints....when I replaced the transmission, I dropped some pins out of the front u-joint...I gathered them up and put them back...but I could have missed a few.

My questions are:


1. What is the EXACT size of the 12 point bolts that secure the u-joint straps in place. I used a 12 point wrench on the front, but replaced them with regular hex bolts about two years ago....I've since forgot the size.

2. How in the heck do you get to the rear bolts in the driveshaft??? There is almost zero room to get a wrench in there :surprised

Any special tools or sources locally that I could pick up to make my job easier?? Like at lowes or Autozone?

Thanks for the help!

shafrs3

I don't know that exact size of those bolts but the 12 point configuration gives a better grip with the wrench, keeping you from rounding the corners when you re-tighten them.

Second question is you need to be a bit of a contortionist. The longer you have a Vette and wrench on it yourself, the more you resign yourself to that.

Put the car in neutral, and while its on jack stands supported in a location that allows rear wheel movement, I like the outer strut rod mounting points for my jack stand location, you can rotate the drive shaft to locate the bolts to the most accessible location. Spray off the area with some good grease cutting fluid, I like Berryman's Chemtool carb cleaner for this. The idea is to get as much gunk off the threads so when you do break the bolt loose you can then use your fingers to remove them fully.

1982CorvetteDude

Thanks for the reply

Bird2Bird told me it was a 12 point 1/4" socket

I def have a lot of gunk under there I'm going to run to the parts store and try some of that

shafrs3

Check the differential snubber cushion and mounting bracket. If the cushion is worn and/or the bracket is loose you will get a clunking sound. And if you find a problem there fix that first, it could save you some time you could use for driving with the T-tops off.

Solid LT1

I agree front Diff mount is shot on your Vette.

1982CorvetteDude

where is the front differential mount at...any pics?

I went ahead and changed the u-joints, they were original so they needed replacing .......but I'm still getting that "clunk" when I throw it in drive....the car kinda dives down if that makes and sense.

I'm thinking it may be the rear end if the diff moutn turns out ok....

shafrs3

See red arrow in pic.

There is another rubber cushion on top of this bracket also. When these deteriorate the clunking commences.

1982CorvetteDude

oh......mine is def deteriorated

where can I get one other than corvette catalogs.....is there a local part number for something like this that I can get at autozone or a dealership?

shafrs3

I got mine via catalog, I guess you'll have to call around. Check to bolts holding this bracket to the diff also.

1982CorvetteDude

Like this?

http://www.ecklers.com/product.asp?p...3&dept_id=1861

I'm Batman

I think I have a VB&P poly bushing kit here, if you want to go that route.

Edit - I do have a kit, but I scavenged the stepped metal sleeve, bolt and nut out of it. My rusty (but serviceable) original might still be hanging around, or you can re-use yours if it's intact. For some reason the Energy Suspension kit didn't come with that part, and I had the VB&P kit laying around. The bolt is a standard 7/16x2.5" part that can be bought at any hardware store.

shafrs3

That looks like the one.

tsdorsey

I just bought a bunch of components from different companies and ended up with 2 of those, bolts and all. I'll sell you one if you want. Ecklers has them for $31 shipped so I'll make it $25 shipped. Brand new in the package. It's polyurethane, not rubber.


-Trevor

1982CorvetteDude

Oops, I just order that sunday, it should be here today

Thanks for the help though

MYBAD79

Go to home Depot or Lowes and buy a cheap angle finder. The poly differential mount is a little thicker than the stock rubber one, I had to cut my poly mount to get the differential angle right.
Here's the problem: the transmission tailshaft usually points down, let's say 2-3 degrees. Your differential input yoke should be pointing up 2-3 degrees, maybe it's only 1 degree....factory tolerances plus 25 years of wear on the bushings.... could be off by a bit.... now, if your new poly cushion is too thick the differential is pointing down. If both yokes are pointing down and you connect the two with your driveshaft you'll have a vibration problem ...

The same applies for left/right alignment but it's more difficult to correct- shimming the trans up or the diff up/down is easy ....

tsdorsey

Thanks for the info, I'll keep it in mind when I put the diff in.


CorvetteDude: Don't worry about it. Let us know how it works out for you.


-Trevor

The Money Pit

The bolts are definately 1/4" 12 point,and if you had a socket that size with a decent extension the job would be a piece of cake.

I used a combination wrench and three beers last night to put my driveshaft back in.

74Blackfoot

My car also thunks sometimes when I put in drive, not all the time though. I am almost certain the U-joints need replacing. I am going to drive it up on the lift tomorrow or saturday and take a look.

My question is this. When I put the car in drive, about 95% of the time the rear of the car feels like it drops a couple of inches. I put the car in drive and it feels like it sits down on me. It doesn't do anything else for the other gears. Is this a bad sign? Or is it something that happens.

Something in the back of mind tells me that one day the car is going to sit all the way down to the ground and tires are going to the comical popping off the axle. Which is not a pleasant thought!

Any ideas on what it is?