driveshaft making noise

[radtad767]

I lowered my 69 c10 5/7.5 and installed disc brakes. My exhaust would not work so I changed it to dump before the rear axle. I thought the noise was coming from the axle hitting the exhaust so I fixed that. The problem still is there. It only happens when I barley push on the throttle. I can accelerate through the noise and when I come off the throttle it comes back until I reach a certain mph. Which makes me think it could be the driveshaft. What do I have to do to fix this?

[jimmydean]

Check for play, make sure your joints are tight and your angles aren't too crazy. Short of that, take it in and get it balanced.

[BIGBLU 72]

is it a trashing/beating noise??

[radtad767]

I put it on blocks and it actually sounds like the ring and pinion gear not meshing good in the rear end. Could it be lowering it so much causing a small angle to cause the noise

[radtad767]

Originally Posted by BIGBLU 72

is it a trashing/beating noise??

it sounds like grinding

[lolife99]

Carrier bearing?
1-piece or 2-piece driveshaft?

[radtad767]

Originally Posted by lolife99

Carrier bearing?
1-piece or 2-piece driveshaft?

1 piece

[Clyde65]

look at the cross member that has the drive shaft going through it, see if the drive shaft is rubbing on it.

[shawno72]

My 72 has the same 5/7.5 drop and I just had to replace the u-joints because of a grinding/screeching sound coming from, what sounded like the rear end. Well when I got the driveshaft out all 3 needed replacement and the one closest to the rear end fell apart. The needle bearings were nothing but rust and dust. After replacement the drivetrain has never been so quite.

[radtad767]

Originally Posted by shawno72

My 72 has the same 5/7.5 drop and I just had to replace the u-joints because of a grinding/screeching sound coming from, what sounded like the rear end. Well when I got the driveshaft out all 3 needed replacement and the one closest to the rear end fell apart. The needle bearings were nothing but rust and dust. After replacement the drivetrain has never been so quite.

but was it fine before the drop or did you put some miles before it started to make noise. I put the truck on the ground after all was installed and went for a drive and it was immediate. Its like it didn't even wear it in. Your probably right but I'm just trying to get a good idea in my head of whats going on.

[shawno72]

It was fine before the drop but when I got it apart the needle bearings were like a fine powder of rust so I think because of new hard angles it might just be making an existing problem more noticeable. You know what I mean? The drop might have accelerated a problem that was about to happen. If you have never replaced your u-joints I would recommend that you do. Its cheap and easy.

[shawno72]

By the way do you have any before and after pics? We love them pics.

[radtad767]

Originally Posted by shawno72

By the way do you have any before and after pics? We love them pics.

Oh yeah I will, I will also go ahead and replace the u-joints

[radtad767]

I just checked summit for u-joints and theres different styles. Whats the differences in the styles and which one do I need

[radtad767]

ok I replaced the u joints and the problem is still there. It is in my my rear end, and I think it might be getting close to failure. I found a guy that has a rear end with 3.42 gears and now I'm running 4.10 gears so I should get some better cruising speed. He says it has about 140,xxx on it. Wants 100 bucks

[Clyde65]

I would open it up and look it over for sure.

[radtad767]

Originally Posted by Clyde65

I would open it up and look it over for sure.

well I changed my mind, I got on the phone with cpp and there sending me 4 degree shims and there deluxe panhard bar set. I hope this corrects the noise I'm hearing. They said my angle of the rear end is probably incorrect.

[lolife99]

Originally Posted by radtad767

well I changed my mind, I got on the phone with cpp and there sending me 4 degree shims and there deluxe panhard bar set. I hope this corrects the noise I'm hearing. They said my angle of the rear end is probably incorrect.

I hope you are right.
I would think pinion angle issues would equal vibration,... not noise.
Keep us posted on your outcome.

[shawno72]

Well I can tell you this on my 1980 SWB I had a horrible grinding noise come from my rear end and it ended up being the pinion bearings not the gears. Personally if you ever want to cruise at 70 you would be better off with the taller gears.