v8vette84

Well I decided to go on the highway for the first time since getting the 3.73 rear I got from a guy into the car I realized that I have a rear end "growl/grumble" (Not a howl) at anything over 68mph. Anything under that its quiet like it should be. As soon at you hit 68mpg it starts growling and vibrating the drivetrain some. It's not horrible but it made me not want to keep going that speed. The faster I went the louder it got. This all started with the rear I installed. I'm assuming thats why i got a good deal on it. The OEM rear never did that. I pushed in the clutch and I could hear it better so it definately sounds like the rear. I only changed the rear so I'm assuming thats the cause. Any ideas what it could be in the diff?

FASTAZU

Did you change the complete assembly or just the gears? Sounds like it was not set up correctly, or the bearings may be bad.

v8vette84

I replaced the entire Dana 36.

Tom400CFI

No. My idea is that it's not the diff, but rather it's drive shaft vibration. "68 mph" is just about the right speed to start noticing drive shaft vibes, and clutch in usually makes it more pronounced/noticeable.

My guess is that a U joint isn't seated right in a yoke, or something related. You could check pinion bearing for slop but that doesn't usually produce vibes under load. I'd have a close look at the drive shaft, Drive shaft u joints, caps, straps, bolts and yokes.

sp361t

yup i agree check your U-joint placement into the yoke.
I got into that with a camaro, when i put the drive shaft back in i didn't get it seated square and at about 40 MPH it would rattle your teeth out.

I would think if it was something with the internal ring and pinion you would notice it all the time

v8vette84

Well I found out what the vibration was. I was driving the car last weekend and all the sudden I heard a clunking in the right rear tire. It would do it under load and slowing down, but would quiet down when I was coasting. I finally got around to checking it out tonight, I found a bearing cap missing on the half shaft towards the wheel. The vibration must have been the cap slowly working its way out of the halfshaft yoke. The clip must not have been seated enough and caused the cap to work its way out. Anyways I'm glad I found the problem. I just need to find myself a good used half shaft (Easy) as I'm not sure if the ujoint wore out the bore on the half shaft. I want to be safe.

Hopefully this info can help somebody in the future. Thanks for all your help!

antfarmer2

Have seen them on fleabay or use some locktight bearing dope.

v8vette84

Well I ordered a used half shaft off ebay. I have to take the shaft to my local shop to have them put the new spicer u joints I ordered in as I do not have a press or even a good vice where I am now. Hopefully they don't screw anything up....

antfarmer2

Do both sides.

v8vette84

v8vette84

Well I got the passenger side done then I noticed the drivers side half shaft outer ujoint was doing the EXACT same thing! So needless to say both sides will have spicer u joints in and out so I won't have to worry about those! I think my problem was when I replaced the joints many moons ago I never cleaned out the groves that the clips sit in so the clips fell out and the forces involved while driving caused the caps to start working their way out of the half shafts.