Rear end play

[NY69]

Since I own this car (like 20 years), there has been some whining in the rear end. Because I have never driven any other mopar besides my own, I am not sure if this is normal or acceptable. Doesn't seem to get worse over the years as far as I can tell. Next time I take her out cruising, I'll try to make a video.

However, since last year, there's also a clunk in the driveline, manifesting when drving, stepping on the gas pedal after decelerating. That needs some attention, and your help would be highly appreciated, since this is uncharted territory for me...

What I've found out myself:
Dif's oil level's OK
Oil looks clear
It's not a sure grip dif
There's no sideway play in the rear axles (width of driveline)
At least the rear u-joint has some play and needs to be replaced (I will replace the front as well).

I've made two video's and I hope to get some input from you guys as to whether or not there is excessive play in my driveline, and maybe if so, what parts might need to be replaced.





Thanks a lot for your input.

 

[Newport 66]

There is a spec. for allowable backlash in the differential. I would replace the u-joints and see if it eliminates the whine. Worn joints can make some pretty strange sounds from chirps to whines.

 

[jake]

Not what I was expecting from the title!! Hehe

 

[polara71]

I eliminated the rear end whine by replacing the rear wheel bearings. After 50 years, they probably need it regardless of noise or play .

 

[Newport 66]

I eliminated the rear end whine by replacing the rear wheel bearings. After 50 years, they probably need it regardless of noise or play .

My 60 year old ear end whines from time to time, not sure bearing will help...LOL

 

[Davea Lux]

After that many years, it would be a good idea to repack and inspect the rear wheel bearings in any case. As noted, replace the u-joints. When you jack the car up, the quick check for a sure grip, if your are curious, is to spin one of the rear wheels, if the wheel on the other side turns the same direction, you have a sure grip. If the wheel on the other side turns the opposite direction, you have an open rear end. 8.75" third members will run a long time with some extra gear lash, as long as it is not howling or chattering when you drive it, I would say you should be able to keep using it, especially if this is an occasional use vehicle. Also sometimes helps to change the gear oil, especially on units that have seen extensive mileage.

Dave

 

[68PK21 440.6bbl]

Rear joint is toast and is most likely the source of all your problems. Front joint is probably tight and on top of that you have some serious brake issues.

Once you get the driveshaft out you can check the pinion for any shake or play (should be none that you can feel) and rotate smoothly with the wheels & brake drums off.

 

[Wollfen]

I recently had to replace a hogshead in a car here as it had a U-joint on the driveshaft that was loose and having replaced it, I noted the car still had a clunk on acceleration and deceleration. I pulled the original hogshead out to find that the pin through the spider gears had worn an oval into the gear housing at either end causing the play, something I couldn't feel by turning the pinion back and forth after pulling the drive shaft out.. I could have replaced the open center but I had a spare hogshead so it was simpler to swap it out.

 

[NY69]

Thanks for the responses.
I'll replace the u-joints and rear wheel bearings first and see what that did.

About them u-joints, l looked at Rockauto and there were a lot of different options, not all interchangeable not sure which one would apply to my car, and maybe a recommendable brand?
Suggestions, anyone?

And the brake issue on the rear wheels will be addressed this week.

 

[NY69]

About them u-joints, l looked at Rockauto and there were a lot of different options, not all interchangeable not sure which one would apply to my car

So, I measured the yoke size to establish which u-joint I'd need:

It measured 9 cm/3,54 inch.
Wich is not an available size on Rockauto or anywhere else....
Did I measure the wrong part or do I have a very uncommon yoke size on my car?