heavy85 Posted April 27, 2006 Share Posted April 27, 2006 Over the winter I swapped my LSD into from the old 3.7 into a 3.9 diff. This helped get more RPM in autox but also fixed the really annoying whine with the old diff. Only a new issue has popped up. Under load everything is fine, under engine braking everything is fine, but in the middle basically coasting with very little load on the rear end there is a very hideous crunch, rattle, marbles ratting around sound coming from the rear end. It's got Redline oil for LSD. Oh yeah and it seems to go away with the clutch pushed in. Any ideas? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 27, 2006 Share Posted April 27, 2006 I think you're going to have to open it up. If it makes the noise when you're not turning its a bearing or the ring and pinion. If it does it when you're turning than its the LSD. Also transmission countershaft bearings make a ball bearing floating around rattle type of noise when they go bad, and the noise goes away when you push in the clutch. Just throwing that out there... Quote Link to comment Share on other sites More sharing options...
jbk240z Posted April 27, 2006 Share Posted April 27, 2006 It sounds like a possible clutch throw-out bearing problem. Does it make the noise at an idle with car stationary, then noise fades when clutch in pushed in? I might be out of the box here, just an idea. Good Luck. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted April 29, 2006 Author Share Posted April 29, 2006 Sound is definitely coming from the rear end. It seems like the gears are dithering when they have very little load on them. Under load or turning everything is perfect just in gear with basically no load it makes this sound. Weird thing is originally I had the 3.9 with no issues, swapped to 3.7 LSD then had a very annoying constant whine but no other issues then swapped the LSD into the 3.9 and now have this new rattling issue? I just put it back together and didn't notice anything unusual so I'm not even sure what to look for if I do open it up? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 30, 2006 Share Posted April 30, 2006 About 10 years ago I had my old R200 LSD rebuilt and the shop that did it F'd it up 2 times. The 1st time it whined, BAD. Now that I think about it the second time it did have a little rattle sound, which was the pinion teeth hitting the carrier. I drove it around the block and then got my buddy in the car to have a listen, and we drove about 4 houses down the street and it locked the rear tires and skidded to a halt. It was a pretty rough road so we couldn't drag it back with a floor jack. We called AAA and they towed it 4 houses down the street with a flatbed. The problem was the idiot at the shop left the pinion nut loose, and the pinion walked off of the ring gear and locked solid against the carrier. Luckily I was doing about 10 mph and nothing was damaged. If I'd been going 30 or more I'm sure it would have been diff carnage all over the road. I'd double check that the pinion nut is tight. Don't need to take it apart for that. If it isn't tight, I'd pull the nut all the way off, put some new red loctite on the pinion and retighten. If it is tight then I'd pull it out, take the cover off, and start turning the pinion and looking for wear or chips on the ring gear. If you're good there, check the backlash. If that's OK then pull the carrier and check the carrier bearings. If they're OK then check the pinion head for damage. If it is OK then check the pinion bearings. If they're OK then the noise was in the transmission. Your noise is IMO a R&P noise because you get the noise when driving straight. In my limited experience that means possibly a bearing, possibly a chipped gear, possibly something left loose that lets the gears move around on each other and make the noise you're hearing. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted June 25, 2006 Author Share Posted June 25, 2006 I'd double check that the pinion nut is tight. Don't need to take it apart for that. If it isn't tight' date=' I'd pull the nut all the way off, put some new red loctite on the pinion and retighten. If it is tight then I'd pull it out, take the cover off, and start turning the pinion and looking for wear or chips on the ring gear. If you're good there, check the backlash. If that's OK then pull the carrier and check the carrier bearings. If they're OK then check the pinion head for damage. If it is OK then check the pinion bearings. If they're OK then the noise was in the transmission. Your noise is IMO a R&P noise because you get the noise when driving straight. In my limited experience that means possibly a bearing, possibly a chipped gear, possibly something left loose that lets the gears move around on each other and make the noise you're hearing.[/quote'] Checked all that - nut was tight, bearings tight, gears look good, even disassembled the LSD and the plates look good, checked rear wheel bearings and half-shafts. Everything looks very good and tight. Definitely sounds like coming from way behind the tranny. One thing I do notice is there is a lot of play between the drive hub (one that's splined in the middle) and the drive plate in the limited slip unit. There is no real sign of excessive wear except you can see grooves starting to form in the drive hub. The symptom of this is if you hold the pinion you can rock each wheel (independantly) back and forward a measurable amount. I've had this diff in another housing (switched from 3.7 to 3.9) and it never made this noise before ... but it did whine really bad which it no longer does. I'm wondering if I have my half shafts phased weird - should the u-joints beween the left and right half shafts be in phase or out of phase with one another. In other works lined up or 90 degress from one another? Last thing as I mentioned above is the noise is only heard with no load such as when coasting down to a slower speed. Step on it and it goes away. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted June 26, 2006 Share Posted June 26, 2006 May want to check all of the u-joints including driveshaft u-joints. They may be the culprit... Quote Link to comment Share on other sites More sharing options...
buZy Posted June 29, 2006 Share Posted June 29, 2006 Had a similar sound awhile back at part/neutral throttle. It was the axel hub bearings but I see you checked those already. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted July 1, 2006 Author Share Posted July 1, 2006 Had a similar sound awhile back at part/neutral throttle. It was the axel hub bearings but I see you checked those already. Hey buZy how did you know it was the wheel bearings? I just spun them and they roll smooth and there is no noticable slop. I was talking to an old time hod rodder on the plane earlier this week and he said just rolling the wheel up in the air and you may not see any noticable issue but put a load on it and it's there. If that's the case trying to work through a diagnosis procedure. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
dapiper Posted July 8, 2006 Share Posted July 8, 2006 Had that on my old 240. It was excessive play in the rear hub axle splines, had to replace entire rear axle and strut assy as unit. Quote Link to comment Share on other sites More sharing options...
buZy Posted July 12, 2006 Share Posted July 12, 2006 Hey buZy how did you know it was the wheel bearings? I just spun them and they roll smooth and there is no noticable slop. I was talking to an old time hod rodder on the plane earlier this week and he said just rolling the wheel up in the air and you may not see any noticable issue but put a load on it and it's there. If that's the case trying to work through a diagnosis procedure. Thanks Cameron heavy85 I had the same sound and the bearings were the only items left to question. Just like yours they felt smooth and tight too. I say that old time hod rodder is right on the money. Bearings can be worn yet seem ok when inspected. Glad to hear you figured it all out! Brian Quote Link to comment Share on other sites More sharing options...
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