anth0nycurtis

Hey Guys,

So as I mentioned in another post I recently got a 1986 Z28 with a Small Block 350 in it. The car has been running good and slowly fixing issues with it but this one has me stumped.

The car runs and drives fine but when decelerating a strange loud almost like a WUZZ WUZZ WUZZ (lol sorry best way I can describe it) is coming from the rear. The noise goes away over 15 - 20 mph and doesn't seem to happen while accelerating only while decelerating. I was possibly thinking rear bearings but I figured this would happen all the time, as well as a rear problem so I'm stumped.

Anyone got any ideas??

Thanks in advance!

big gear head

Check the pinion nut and see if it's tight. Torque it to about 125 foot pounds and see if the noise goes away. If not then you porbably need to replce the pinion bearings.

Edwardgp

I agree with big gear head and would like to add if it has been going on for a long time you might have to dig deeper into the differential. Check the rear end fluid when you drain it for metal pieces.

TTOP350

iTrader: (8)

Yup, sounds like a pinion bearing issue. check all the bearings tho.

anth0nycurtis

Hmm, Think it's worth fixing or would you guys suggest I just get a used rear from a junk yard, build it up and put it since the car is still driving fine at the moment. The noise doesn't always happen either, when you first start off its fine it happens after a few minutes of accelerating and decelerating and like I said, only at low speeds.

Also its worth noting that the rear brakes are having some issues as well, last time we had it on the lift the e-brake really stiff and didn't completely disengage so we're thinking the rear calipers might be semi-frozen. Is it possible that maybe one of the rear brakes are causing the sound? Every time I hear it I second guess myself, I either think it's coming from the rear driver side, or the center but I can never tell for sure.

Thanks for the leads!

big gear head

I wish you were closer. I've got a disc brake 7.5 housing with all of the brakes on it that I'd like to see gone. If you are going to rebuild a used rear end then that should work well. If you were just going to put a used rear end in without doing anything to it then that would probably be a waste of time because it would probably have as many problems as the one you have now.

anth0nycurtis

Ahh, that'd be nice, I have a feeling the driver side caliper is gonna give me some issues. Hopefully it's just the sliding pins and not a whole new caliper.

Yeah I wouldn't toss on an already beaten rear, if it turns out this rear is shot and on its way out I'll just run it till I can't run it anymore and in the meantime pick up one from a yard around here and start building it in my spare time. Rears are never fun to repair while actually on the car lol.

Here is a picture of my Car, picked her up for $850 has a GM Goodwrench 350 in it with an Edlebrock intake and Holley 600 carb.

Hello, Michael

Do you know what gear ratio you have? I have 3.70s in mine, and I've heard they tend to be noisy. Mine whines during decel also. All my bearings are new and it runs and drives fine. No clunks or chatter.

big gear head

If you have a 3.70 then you must have the 9 bolt BW rear end. All of those 3.70 gears make noise no matter how well you set them up.

DrewsCam

iTrader: (2)

my best reccommendation is to take her to a tranny shop that will inspect the rear end for free.... I had this done on my 82 z28 and the guy brought me out with the car in the air and the differential open and showed me the spider cracks in the gears. I had the ring a pinion replaced by the same shop for around 75 bucks out the door and had no problems with it until I lost the car...

Hello, Michael

Yep. I've got the 9 bolt.