There's a not so pleasant metal on metal "clank" sound coming from my rear end when I shift from Neutral to Drive, and Neutral to Reverse.
It seems to be coming from the neighborhood of the rear differential, but I can't tell if it's coming from inside the diff, or maybe from the drive shaft itself.
Anyone had this happen before?
Any ideas on how to diagnose it further?

 

Check your u-joints Mick-e. They get sloppy and noisy, then they get hot and snap. Cheap to fix before they break.

 

My 79 f250 always had a little clunk and I thought it was the gears getting sloppy. One day I took off for a car show and it was worse than normal. I make it about 2 miles down the road and the driveshaft flies out! Anyway, check your ujoint straps!

 

I had the same situation..had a clunk going from reverse to drive and back and mine turned out to be the posi unit in pieces and the ring gear missing teeth. Have someone put your truck in gear a few times and watch the driveshaft..see if it grabs a tooth immediatly or spins before snagging a tooth. That was how I found out.

 

Park it on a flat spot. Set the parking brake so you don't run over yourself. Put it in neutral, don't start the engine. Crawl under it and twist and push on the drive shaft. You'll soon find the source of the noise.

You can move the truck quite easily by twisting on the driveshaft, so be sure it won't move when you get under it.

 

That makes sense.
I'll give that a try. Hopefully it's just U-joints, and not in the rear diff.
Thanks everyone

 

An old suburban I had made that sound. It was the rear end having a lot of slop in it.

 

Exactly why I'm tearing the diff apart to replace the clutches in the limited slip. I have all new U-joints, new carrier bearing and I still have the clunk... It's the rear center section losing it's grip..... Faith has some pix in her gallery to show what happens.


https://www.dieseltruckresource.com/...7&ppuser=21682


https://www.dieseltruckresource.com/...4&ppuser=21682

 

****
that is not a good sign.
How hard is a differential rebuild?

 

Well, truth be told...

I have no idea, as I've never rebuilt .... or actually disassembled a 3rd member before.... so I got some quick learning to do......




I've rebuilt several engines, and they all ran fine. Hopefully it's not as complicated.

 

It pretty much sucks! I had the clank sound in mine too, but the guy I bought it from told me he just re did the rear end. Turns out he didnt shim it so the gears had some play back there and one day I was driving down the highway and heard one big a** clank followed by a bunch of clanks and some teeth were ripped off the ring and pinion and I had to re build the rear diff. . . it wasn't too fun.

It could be u joints though and if its not then maybe the re build wont be too bad for you. It was my first one so ya. Good luck.

 

If the coupler from the trans to transfer case is anything like it is in the 5-speed it can make noise too. It's not something that you would just notice one day though. It would slowly get louder over time.