Clunk elimination has begun, with pics

[Zedyone_kenobi]

Forward position it is then. Good explanation. Something for a future project

Negative on the backlash, I did not. I started to get weary of driving the car with the diff the way it was 45 miles across Houston to the Z shop. With my 6 month old, it would have been hard logistically to get somebody to follow me and give me a ride home.

However, my 'new to me diff' appears to have the same amount of free play when I turn the pinion, so you were correct, in that you cannot check for backlash by turning the pinion. I am not totally sure I have done the necessary legwork. I was done speculating, and decided to pull the halfhafts, drive shaft, diff and mustache bar and replace all the bushings before I just swap out diffs. I will pull the covers of each to see if there is any metal shavings or if the bearings look worn. Surely the entire ring gear should not move around inside the diff housing. I will look for obvious problem areas, then put a new gasket on the best diff, paint it and start to assemble it.

I may need to check out the tranny mount while I have the car up on jacks. It may need some attention.

But I dont want to get carried away. With relatively low miles, certain parts should be fine. Its that whole 37 years old thing that makes things tricky.

[JimmyZ]

The Ron Tyler style mount took care of my clunk. The spacing IS different for the bolt holes so you'd have to design from scratch. WELL worth it though. Tightening all four mustache bars to torque spec is good too.

See if you have a driveline shop in town. (Ask speed shop) Having the driveline shop balance and inspect the halfshafts and driveshaft would be the best thing to do. They can also inspect and shim/adjust your ring and pinion. My local shop will go through a diff for $180.

FWIW

Jim

2c

Jim

[DougN]

Alright, I see you've copied my copyrighted personalized license plate for your Z, now you're going to have to pay me royalties! Everytime someone gives you a thumbs up or other positive comment about the car you have to give me $1

[Zedyone_kenobi]

DRAT, I had no idea, I figured somebody on this board had to have that somewhere in the country. I figure there is little chance we will bump into each other, although, if I do see you, I will buy you a beer.

[Carl Beck]

The Ron Tyler style mount took care of my clunk. The spacing IS different for the bolt holes so you'd have to design from scratch. WELL worth it though. Tightening all four mustache bars to torque spec is good too....

Jim

Some time ago - Jon Mortensen posted a link to Paul Richer's solution to the differential mount/nose strap. I copied Paul's instruction sheet - but deleted the old URL he had as it is no longer any good.

I think this is a very elegant solution - easy to fabricate at home and it does the trick. I would think that Paul's approach would be fine for most L6 powered Classic Z's. I should think that for a Z running less than 225HP - one could use even thinner steel stock to work with.

Good thing the image of the information sheet was captured, rather than just the original URL..

FWIW,

Carl B.

[Zedyone_kenobi]

Project Update:

The passenger side half shaft was pulled off and it is just as tight as the driver side. There is absolutely no slop in the ujoints that I can feel by hand or when I grab each side with a wrench and twist. The motion is smooth and fluid. The drive shaft put up little resistance and its u joint felt just as tight. So I still need to decide if I am going to replace all of them or none of them. I started to loosen the bolts to the differential and realized I may have to make a decision. I am not sure how I want to tackle that. Of course I want to remove the least amount possible, but still do the job right.

THe back bolts to the diff are a piece of cake. Its getting the front lose and out that seems to be more of a challenge. Seems I could do it in several ways.

1) Loosen the arrestor strap and unbolt the nut holding the mount on and pick it right up and over the crossmember

2) Unbolt the two bolts holding the mount to the diff and then just pull it straight out, but those seem impossible to get to

3) Loosen the 4 bolts holding the crossmember to the chassis and lower it a little enough to pick the diff with the mount attached over the crossmember and out to freedom

Either way seems feasible.. but for those who have done it before, what do you recommend.

Pics for clarity included. Also, I have been pinging on the numbers on the bottom of my diff, here they are as well. Any clues to relevance?

[doradox]

Search for diff removal. One of the members recently posted very concise instructions.

Steve

[Diseazd]

Carl.....Anyone making the bracket that you show.....my metal working skills ain't too good! How about it Jimmy Z......something that you could machine? I'll take three. Guy

[Pop's Z]

Stephen, Remove the diffy via #3. I did this a week ago w/o any problems. It's much easier to deal with that way. Don't forget that when you put it back together you need to pre-load the suspension before tightening those four bolts and the big mothers that hold the bushings.As far as the u-joints go...If it ain't broke, don't fix it.

Cheers, Mike

[Zedyone_kenobi]

I have been looking at parts drawings and reading more on the web here an other places.

Mike, I am going to take your advice as it seems number 3 is the best method. I was initially concerned with just dropping the crossmember and leaving the back part of the rear a-arm still attached to the frame, but the more I read on it, it seems to be fine.

#3 is also more attractive as its quite easy to get my impact wrench on those bolts as NOTHING is in the way.

More pics to follow after I get the diff out, probably this weekend.

I assume when you mean big mothers that hold the bushings, you mean the mustache bar?

[jmortensen]

Sorry for the threadjack zedyone...

Carl.....Anyone making the bracket that you show.....my metal working skills ain't too good!

I don't know about Carl, but I don't know anyone making the bracket. It should be SUPER easy to make, and would make an excellent first time fabrication project. The tools required for the fabrication could be as simple as a hacksaw, vise, hammer, and drill. Buy a piece of 1/8" x 2 strap from the hardware store. Buy a rubber foot for a table while you're there. Cut the strap to the length required with the hacksaw. If you can't figure out how to measure it, mock it up with a piece of cardboard. Drill holes in metal for attachments to the diff mount and for the stud on the rubber foot. Put metal in vise and bend with hammer. Paint. Bolt foot to metal. Put new part in place and mark hole locations on the diff mount. Drill holes and mount. That's it.

The only part that might be tricky would be bolting the new part to the diff mount. I can't remember if the rubber on the inside of the mount hangs down low enough to prevent a nut and bolt from easily being installed. If that were the case, I'd run my new part down to the nearest muffler shop and have them weld it on. If you needed to get it off later, just have the welds ground off. Or, if you have a tap and die set, drill the holes and tap them so the bolts can screw directly into the stock mount.

I think this thing will hold a lot more than 225 hp too. It would have to be a LOT of hp to tear the strap.

Edited September 4, 2008 by jmortensen

[Mike]

I had the same problem. After replacing the U-joints twice I finally got rid of it by replacing ALL of the bushings in the back-end of the car. Mustache bar, diff mount, strap, and of course the U-joints.

Some advice on the u-joints... don't go cheap here. Buy the best U-joints you can find. I eventually went with stock replacements but I am sure there are better ones out there now. I recommend doing everything because you probably don't want to take the back-end apart again. Get it over with and do all of the bushings now.