Help needed - Strange noise

[andymo1972]

I recently swapped out my 3.07 rear end for a 3.55 rear end and after I put my new rear end in, I am getting a strange noise that I'm not even sure is rear end related at this point (I swapped complete rear ends with someone and he was driving on his rear end up until we swapped). When I got the rear end, I replaced the fluid with the recommended Mopar fluid and Anti-slip additive before i put it back in.

Now, on to the noise. I searched and saw a post on a rattling noise that sounded like metal washers rattling that went away once the fluid worked in. My noise sounded EXACTLY as described in that post but I have ~80 miles on the car since the swap and it is still making the noise. At low speeds, I hear the noise only when I let off the gas and the car is in gear. Putting in the clutch or any pressure on the gas pedal and the noise is almost instantly gone. At high speeds, I also hear the noise in neutral coasting down a hill. It does not seem to be engine rpm based but wheel rpm...the faster the wheels are spinning, the faster the noise is, except that it goes away anytime I put any pressure on the gas pedal. I put the car up on jack stands, started it, put it in gear and let the clutch out, gave it some gas and let off...no noise. I upshifted a couple times...no noise. I downshifted a couple times...no noise. Could it be a problem with the clutch that just happened to develop at the time I did the swap?

Not much else has changed. While my car was apart I added some chrome smooth tubes. Then after I got the rear end installed I added a speedo calibration box but the noise was there before the box was installed.

Anyone have any ideas?

Andy
97 GTS

 

[JonB]

Did you install with new bolts/straps as highly-recommended? Or did you use the old stuff? That could be the problem.

I would check the pinon yoke that fastens to the driveshaft.

Jack up the car and see if there is ANY play there at all.

The noise you describe would indicate to me some play in that pinion/yoke. Please report back?

 

[andymo1972]

Jon -

I was not aware that I needed to put new bolts/straps on until I read a post you made regarding the recall and how they should not use the old stuff. I ordered them from you last week (along with Magnecore wires and plugs) and am waiting for them to arrive. I had the recall done before I installed the rear end and the tech kept the old stuff on also so that might make sense, especially if they've been on/off twice! Hopefully I get the bolts/straps today and can change them out. Thanks for the info, I'll check things out tonight when I get home.

BTW - I got the Magnecore wires and plugs and as soon as I get this prob worked out I'll put em on. Those Magnecore wires do look nice though!

Andy
97 GTS

 

[andymo1972]

Geoff - I think I sent you an email after reading your post on that topic. And yes, your description matched mine.

Jon - No prob on the name thing and I appreciate your advice even if you don't know who I am

Thanks for the shipping info, looks like snow this weekend possibly so I can get things back apart and ready to put the new stuff on.

Andy
97 GTS

 

[Jack B]

If the ring and pinion clearance is not correct the noise is the loudest right where you describe it. That noise is more of a whine until the the gears start wearing, at that point the sound and wear are exacerbated. This is easy to diagnose visually.

 

[Geoff Green]

I put a complete new 355 rear end in a couple of years ago and had the same noise for a month and a few hundred miles. After that everything was fine. I also asked this same question back then and described it exactly the same way. Check everything out, but don't worry.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by andymo1972:
Jon - I was not aware that I needed to put new bolts/straps on until I read a post you made regarding the recall and how they should not use the old stuff. I ordered them from you last week Andy
97 GTS <HR></BLOCKQUOTE>


Your strap/bolt kits should arrive MONDAY.....

Screenames here never seem to translate to my customer database! SORRY I did not put 1+1 together. But the advice stands..

 

[andymo1972]

Update - no more noise: I put the car up again and checked for any play in the driveshaft and half shafts and everything was very solid (still gonna change the straps and bolts when they arrive from partsrack). Since the weather was ok here despite the forecasts...typical...I took the car out today and the noise was completely gone! I guess it was just a fluid issue as a few of you had told me it was. I just got worried that I put so many miles on it and it was still there and didn't want to take any chances.

Thanks again for the info

Andy
97 GTS