98ZEMT

iTrader: (5)

Hey guys. Big problem. This is on an A4 98 Z. I just swapped rearends with a guy a month ago because he had a rearend with 3.73 gears. I didn't pay anything for it just had to do the work. Problem is, its been whining. I've gotten over the whining sound. But now tonight, coming off the interstate, I just let it coast down from 75 and it made the most God awful grinding sound on the right side. Now, if you take off leaving the shifter in 1st, it doesn't make the noise while accelerating, but as soon as you let off the gas, HOLY ****. It is loud. Sounds like your trying to shift a manual transmission without using a clutch. Just shoving it in gear. That kind of grind. But worse. Is this a wheel bearing? Or worse. Thanks.

fleetmgr

worse

98ZEMT

iTrader: (5)

Could you elaborate?

EDS01SS

iTrader: (30)

Sounds like a bad pinion bearing. You should get it looked at right away before it does become worse if it hasnt already. If that bearing comes apart or has already started coming apart plan on buying new gears and axles.

98ZEMT

iTrader: (5)

Well that sucks. Call me lucky I guess. Is this something I can replace myself? I assume I have to have a shop push the bearing out and install new one. God this sucks.

pjb

iTrader: (2)

if its coming from the right side, and not from the center of the car, its probably an axle bearing.

98ZEMT

iTrader: (5)

It definitely sounds like its coming from the right side. I can't be 100% sure but it really sounded like the right side. I guess we'll pull that axle and the dif out and check. Is there anyway to know if the pinion bearing is shot without pulling it out?

pjb

iTrader: (2)

if its as loud as you say it should be easy to determine if its coming from the center or out by the wheels. have someone ride/listen in the back seat. put your ear to the carpet between the rear seats. if its out by the wheel, I would replace axle bearings and leave the rest alone.

98ZEMT

iTrader: (5)

I will try to do this when my girl gets home. I also thought about putting it on jackstands and running it up in gear to see where its coming from.

fleetmgr

Doing this along with using a stethoscope will pinpoint it.

quews6lime

iTrader: (22)

axle bearing...it all most sound like your brakes are bad huh?

98ZEMT

iTrader: (5)

I'll try my best to check tomorrow. Its really been a rough week so I may not be able to. But I have to get this fixed. I'll report back as soon as I hear something. Thanks everyone.

98ZEMT

iTrader: (5)

OH MY GOD!!!!!!!!! I just got under car to look while it was running. I noticed the yoke going into the transmission was moving in and out with the engine running and the car up on jackstands. I look back at the rearend and the other part that holds the driveshaft to the rearend was moving in and out and round and round about and inch!!! I could kill the guy who traded me this crappy rearend. I should have known if its too good to be true, it probably is. Do you think I'll need to replace the gears?

fleetmgr

If it's the companion flange doing the moving, without a doubt.

Jawsgear

iTrader: (2)

Preload was set imporperly, Bearings are most likely toast, hopefully the gear did not get damaged. You need to crack the diff open ASAP and do not drive it unitl fixed.

98ZEMT

iTrader: (5)

Thanks man. May try to take pics of the damage tomorrow. The pinion gear went further back into the case, contacting with the differential. It made a gear pattern on the diff itself!!! I'm in shock and awe. I will definitely try to get some pics. I believe they will be interesting for all to see!!! I have not noticed any damage to the gears themselves. Is there anywhere in particular I should look? All teeth seem fine. Also, what all do I need to replace? I know apparently the inner and outer pinion bearings, pinion nut and crush sleeve. Anything else? Thanks.

98ZEMT

iTrader: (5)

And yes. That's what it was. Sorry. Couldn't think of what it was called!

Jawsgear

iTrader: (2)

I would look at the end of the pinion teeth where it came in contact with the carrier case. Also check the carrier for any potential cracks from the pinion hitting. Depending on how bad it might need a carrier assembly as well.

Comapinion Flange or Pinion Yoke is the proper termanology.

Jeff

98ZEMT

iTrader: (5)

Here is the extent of the damage. The bearings and pinion shaft appear fine. It doesn't look like the crush sleeve ever got crushed!! And they reused the old pinion nut when they installed it. What idiots.

98ZEMT

iTrader: (5)

What is the pinion nut supposed to be torqued to? And the main differential bearings? You said something about preload. How do I check that? Sorry, I just really want to get my car back up and running and can't find this info anywhere.