I wasn't getting any replies over in the rear end forum so got permission for another thread. Maybe you guys will know something about it.

I replaced my drive shaft a few months ago new u joints. I been getting a pop randomly even since. Only when starting off mainly when I'm starting off on a hill. I've been busy and ignored it finally decided to figure it out and it looks like slop in the rear diff.

There isn't any side to side or up and down play. Its backlash when I turn the pinion. I took the cover off no visible metal in the fluid, nothing looks broken. Its hard to tell but it almost looks like the whole assembly is moving up and down with rotational force on the pinion. I made a video but you can't see it in it. You can hear the clunking though.




So last week the shop starts telling me they can't find anything actually wrong. That everything is just worn. That I should replace everything including the axle shafts. So I say are the axle shafts that worn can't you tell? They say we can't say for sure you probably don't need new axle shafts but we just want to cover everything so you get rid of your problem. Great they give me a lot of confidence. I had them get me another price without the shafts price is more reasonable but now I don't trust them.

Can't find a used rear at a decent price or a another shop that wants to work on it. Did find a back yard hillbilly guy on craigslists that sounds like he knows what hes talking about. So now im torn do i let the idiots where its at now do it or do I go take it back and find another idiot or let my ******* do it. That or keep looking for a used one a good price.

 

More info. Found a used one 2 hours away with 170k for $650. Shop wants $900 for ring and pinion, loaded case all new bearings. If I go used I'm guessing ill have to pay a diagnostic fee. Times a consideration too. I have business to run and my beater cargo van might not make it to pick up the used axle or last two more weeks of calls. Shop will have to order in parts and take there time getting it ready. If I go with the used one I can pick it up tomorrow and get it in this week.

 

Did you replace the Drive shaft and U-joints or just the U-joints?

Did you have the random pop sound before you replaced the parts?

Could it be a problem with one of the new U-joints?
Do you have a center bearing carrier?

Could you describe the pop as having more of a tinggy sound to it, like echoing through the drive shaft?

With nearly half the parts you buy these days being bad when you get them,, perhaps one of the new U-joints is bad,, ???

 

Driveshaft too I managed to mess up a yoke trying to do the joints and they couldn't get a new yoke to weld on so they had to get a whole new shaft. It is aluminum and yes it tings. Completely different sound with the new driveshaft thats why I let it go for awhile figured it had to be something to do with it wasn't too worried about it. Driveshaft and u joints checked out good. Its a one piece.

When I pulled the driveshaft and made the video of the pinion. I sent the video to my most trusted mechanic buddy he said he had just rebuilt a dana 70 at work something was definitely wrong and he didn't want anything to do with it. Differing opinions before I tore her out though some of my mechanic buddies thought it was normal backlash others thought it was way too much. Something didn't seem right to me so I tore it out to take it to what I thought was a great shop. At least it was the only one that was recommended and would work on the thing.

 

so has anyone actually measured the backlash? hard to see much from the video.


I have a 60 semi in my van and it has had a coast vibration and noise in it for 3 yrs now, hasn't got any worse. been through 2 rear ujoints since, I load the hell out of my van and don't really baby it under load either.


the sound you are describing as your complaint/worry does sound like its a Ujoint or a driveshaft. I have replaced a Ujoint and done it again within 3000miles as I did not do the grease job between my services and it had one cup not taking grease.


to properly check your backlash you need to secure the pinion yoke and move the ring gear back and forth and measure the backlash with a dial guage.


I don't think you have a rear end problem.


load and hauler:

 

Wish I would of posted here 2 weeks ago instead of the axle forum. I should of just left the axle in the truck and ran her til she broke, I was hoping to fix it before I destroyed it. Oh well the shop I don't trust said shes definitely wore out all around who knows though shes in pieces now, went and got the used one yesterday. I'll find out where the noise was coming from soon enough.

 

A local outfit, Drivelines Northwest, told me that people come in with cheap U-joints bought from big-name auto parts stores, and that these are frequently so bad that they can't balance the shafts . . . . Having been guilty of buying the cheap ones, I now let Drivelines Northwest or some other driveline specialist supply the joints. I do the same with brake linings, and go to an old, long established specialist to get the good stuff. Not saying this is your problem, just an idea.