trying to help a friend... question

[72zcar]

Hey,

I have a 350 powered 72... but this is not about me this time haha. My friends 71 (L28) has play in the differential. The car sometimes makes a clunking noise. we jack up the car in park the differential has some play in the rear end. All the u joint look fine. When one person holds one half shaft still and the other moves the opposite halfshaft there is maybe a half inch of play. So, this is not good right, and is most likely causing the clunking... right. So if this is the problem with the rear end what's wrong and how do we fix it. Should we replace the whole unit or can we repair the old one... aaauuhh its clunking

http://www.72zcar.50megs.com/

[Tim240z]

Better test would be to hold both half shafts still and see how much play is on the driveshaft. Most likely the crownwheel and pinion are just worn out. Just go to the junkyard and pop another one in.

Tim

[72zcar]

ok Tim we will try that... thanks

 

Is this repairable with the unit in the car or do we take the rear end out. Also, his is a 71 so what yr zs whould be a good to look for at the dusty yard. Thanks, Bob

[Tim240z]

Definitely have to pull it.

I seem to remember that the very early Zs had a different mustache bar, but I'm sure that any diff from 70 to 78 will do.(later one will be R200, upgrade?) Maybe grab the mustache bar also.

Tim

[QWKDTSN]

The early Zs had the diff placed more forward in the car. Later Zs used a curved mustache bar to place the diff back, straightening the angles of the halfshafts for less vibration. There are several articles around the net regarding what you need to pick up if you want to set the diff back. I've done it and it's no big deal.

[72zcar]

Ok got it... thanks for the help. So, replace the whole rear end... I kinda new that but I was hoping there was a way to swap out the parts inside without removing it from the car.

 

So, since this is a 71 and the mustache bar is different. In the 72-78 (is this right) the rearend is farther back in the later models.

 

My question now is if I put a rearend and mustache bar in the 71 from a 72-78 will I be able to use the drivline I have now or since the rearend is farther back will the driveline be too short.. crap I hope some of this makes sense

[dmanzo57]

Bob,

 

You can have the original R180, mustache bar, and driveshaft from my '72. Just come pick them up in Gilroy. The diff was working fine when I swapped it for a R200.

 

Don

[Pop N Wood]

Don't be too quick to replace the diff!!! This might not solve your problem. Check all of the differential/rear suspension mounts first.

 

Probably the #1 source of rear end clunks is a broken front differential mount. Also make sure the mustache bar bushings are in good shape and all rear end bolts are torqued to spec. Torque the nuts on the mustache bar bushings and the two bolts that hold the diff to the bar.

[Guest Anonymous]

Agree, listen careful does it sound like a real metalic clunk, or is it a dull thud like someone dropping a bowling ball on rubber. If its the later its the front mount, mine makes the same noise currently. You have to shift pretty smooth to not make it thump in my car. I need to fix it but need to put a R200 in first, no use fixing the R180 mount, I'll need to replace it anyway along with the mustache bar.

 

Regards,

 

Lone