-Z-

I just bought my first 1982 280ZX Turbo Automatic and everything on it was PERFECT till I was going down the highway at about 70 and the rearend started "klunking", I was told it was the driveling but i'm not sure how to find one and how to be sure that's what it is. If anyone has any info on that please let me know!

icice9

could be your half shafts.. but id jack up the rear end and set it on jack stands.. start her up and put her in gear and inspect the moving parts.. you should be able to track down the problem from there

NismoPick

^^^ indeed... could be the half shafts, diff mustache bar, or some of the 4 long "diff to crossmember" bolts could be loose.

-Z-

Well I notice that she only really does it when i'm doing highway speeds or halfthrottle... if i'm going slow enough then she will only do it every once in a while but when she does do it then it's LOUD. It stops when I press on the brakes so could it just be something with the brakes?

icice9

brakes will make more of a grinding noise if theyre bad..

SportBikeMike

I though rearend klunking noises were just one of the joys of owning a Z-car...

NismoPick

It shouldn't / doesn't need to be...

Bleach

In a turbo car like yours you have CV joints in back. It is unlikely they are clunking. Its probably just the bushings holding the rear suspension in. Two on the crossmember, and one on the back of the differential.

When you apply power forward the diff twists one way and is held against the car. When you back off the throttle the engine slows your car down a bit and the driveline and pressure on the diff is reversed. The slop in your bushings allows movement. That's the basic reason most Z's clunk in back. Your auto applies a little pressure forward all the time at slower speeds. If you had a 5-speed you'd probably hear a little clunk every time you accelerated.

-Z-

Well on my Rx7 the rear diff is loose and it klunks but it is not the same klunk. This one also has a grinding noise at 60+ miles an hour when you're on the throttle or not. This noise sounds like it is coming from where the driveshaft meets the transmission (right under the shifter). There is a clicking, (like you would hear in a front wheel drive car going around a corner with bad cv axels) only this happens when you try to keep the car the same speed cruising down the highway. In order to keep the sound mainly away on the highway, you have to accelerate up to 60 miles, then you have to back off till it hits around 50 and repeat...

I was thinking it may be the ujoints. Could the driveshaft make all this noise? And anywhere to find a driveshaft for this car?

icice9

before you start buying stuff... do the inspection... jack it up and check all the moving parts...

-Z-

I've had it up. Nothing is really loose. Brakes need replacing, which accounts for the grinding during movement at low speeds (high speeds I've got louder problems ) When moving the back wheels by hand, the driveshaft would make a decent "tink" which I would assume to get louder with the force of the engine/tranny putting lode on it, not me moving it. There was only a slight more slop in the driveshaft than anything else I've messed with.

It used to be a little klunk noise but then I went up a hill one day, and it got 10x worse. That's when the winding noise started to come at 60+ I am 99% sure that I need a new driveline with just where the winding noice comes from. The winding comes where it goes in the tranny and the clunk comes from the end that goes in the differential.


And just to clarify, clunk twards the rear end sounds like a broken cv axel, not the differential hitting the car.

lww

The driveline is everything from the motor back to the differential including the transmission and drive shaft. The drive shaft is just the piece between the tranny and the differential. I assume you're talking about the drive shaft when you say 'driveline'.

Where in Cali are you? If your u-joints don't have any noticible slop, then it's most likely a problem with your ring and pinion gear in the diff or the tranny itself. Sounds like it's time to have it checked out by someone who knows these cars.

-Z-

I'm in Eureka, California. Yeah I need it checked out but I don't really have the money to take it into the shop AGAIN. I need to figure out what it is and what to do about it. I really enjoy this car so there's no way that i'm willing to get rid of it.. maybe trade it in for another one someday when I get it fixed up. My brother looked at the car and said that the diff looked fine but I didn't know of anyone being able to just look at the diff and be able to tell if it's "good" or "bad". I'm not sure what it is but I am getting annoyed of knowing I have this great car but not being able to drive it because of whatever it is wrong with it so all your help is needed!

Bleach

Replace the oil in the diff and your auto tranny. Its a start. And keep an eye out for another R200 3.54 diff

-Z-

Any R200 Longnose ( should work right? Being as though I have the tripod half shafts, (Okay, drive shaft - side. I am used to refering to the "drive shaft - front (Propeller Shaft)" as the driveline. The tranny back as the drivetrain. And the "drive shaft - side" as half shafts. I do apologize for the mis-interpretations on my part.) I should be able to pull out any side flange currently installed in the differential and use my half shafts. The front differential mount should be the same. If the companion flange is different, I could just swap that aswell. And since I had a R200 to start with, I don't need to worry about the rear transverse link mount being different.

Is there anything else to consider? I believe the junkyard down here has an early 300zx n/a. Should be as straight forward as possible with the only considerations being stated above?

Bleach

The 300ZX (Z31) will have an R200 you can swap in. Probably 3.7 gear ratio