My diff sounds like a jet engine!
Thread Starter
I am the stig.
Joined: Aug 2005
Posts: 614
Likes: 3
From: San Diego, CA
My diff sounds like a jet engine!
Audio clip from a few minutes ago... (In mp3 format, podcast anyone?)
http://www.clanwhy.com/twofer/fc-diff.mp3
That's with my digital camera sitting in the rear cargo area facing up, just behind the storage bins, on the passenger side.
So here's the problem. My new LSD sounds like a jet engine. It's dependant on speed, regardless of being in gear, accelerating or slowing down. It doesn't feel any different than my old open diff, and seems to be locking up properly. It also doesn't do anything wierd when turning. I installed it with a friend yesterday and when I took it for a drive today, it started making all kinds of noise.
Stats:
S4 Clutch type LSD
50-80k miles
Probably never rebuilt
Worked fine with the previous owner
Redline 75w90 Gear Oil (Contains LSD additive.)
MMR-Direct Poly Diff Mounts
Stock front mount
Background story:
One of my buddies pulled it of a junkyard car with about 50-80k miles on it. It's got the LSD tag on the fill hole and both wheels turn together. He had it in his car for about a year before he did a turbo swap and I bought the diff from him. I rode in his car with this diff and also helped him remove it. I filled it up with Redline 75w90 while it was still out of the car and installed the MMR Mounts. Yesterday I borrowed the use of a lift to install the diff with the help of another friend.
Note: It is possible to swap diff's without dropping the subframe, I did it yesterday. Man is it a pain in the *** though. With the poly mounts, there isn't alot of play to move the diff around, so getting to that front mount is quite possibly the biggest pain in the *** possible.
Anyhow, all of the front diff mount bolts went in and were tightened by hand, the rear mount bolts were tightened with a impact gun. After getting the diff back in, we bolted up the exhaust and other crap that was removed and took it out for a spin.
In a nice empty parking lot in an industrial area, we did a few figure 8's at low speed when my buddy says "Hey, why don't you slide it a little?." I double clutched into first and gave it some gas. After a couple of minutes of sideways sliding fun, I let him drive a bit and he did the same thing. (Though I was sure he was going to understeer into a bush.) My buddy does offroading and has a LSD on his jeep and commented that everything seemed to be locking up fine and seemed to be normal. On the trip home the only odd thing I noticed was a low pitched rumble from what I assume are the poly diff mounts.
Today I did a bit of residential driving (low to mid speed) and noticed the diff makes quite a lot of noise. It's damn loud too. Sort of high pitched, like a jet engine, and gets louder the faster you go. I had a look under the car and didn't see any spilled oil or any oil on the diff.
Any thoughts on what it could be, and what I should check?
Thanks!
http://www.clanwhy.com/twofer/fc-diff.mp3
That's with my digital camera sitting in the rear cargo area facing up, just behind the storage bins, on the passenger side.
So here's the problem. My new LSD sounds like a jet engine. It's dependant on speed, regardless of being in gear, accelerating or slowing down. It doesn't feel any different than my old open diff, and seems to be locking up properly. It also doesn't do anything wierd when turning. I installed it with a friend yesterday and when I took it for a drive today, it started making all kinds of noise.
Stats:
S4 Clutch type LSD
50-80k miles
Probably never rebuilt
Worked fine with the previous owner
Redline 75w90 Gear Oil (Contains LSD additive.)
MMR-Direct Poly Diff Mounts
Stock front mount
Background story:
One of my buddies pulled it of a junkyard car with about 50-80k miles on it. It's got the LSD tag on the fill hole and both wheels turn together. He had it in his car for about a year before he did a turbo swap and I bought the diff from him. I rode in his car with this diff and also helped him remove it. I filled it up with Redline 75w90 while it was still out of the car and installed the MMR Mounts. Yesterday I borrowed the use of a lift to install the diff with the help of another friend.
Note: It is possible to swap diff's without dropping the subframe, I did it yesterday. Man is it a pain in the *** though. With the poly mounts, there isn't alot of play to move the diff around, so getting to that front mount is quite possibly the biggest pain in the *** possible.
Anyhow, all of the front diff mount bolts went in and were tightened by hand, the rear mount bolts were tightened with a impact gun. After getting the diff back in, we bolted up the exhaust and other crap that was removed and took it out for a spin.
In a nice empty parking lot in an industrial area, we did a few figure 8's at low speed when my buddy says "Hey, why don't you slide it a little?." I double clutched into first and gave it some gas. After a couple of minutes of sideways sliding fun, I let him drive a bit and he did the same thing. (Though I was sure he was going to understeer into a bush.) My buddy does offroading and has a LSD on his jeep and commented that everything seemed to be locking up fine and seemed to be normal. On the trip home the only odd thing I noticed was a low pitched rumble from what I assume are the poly diff mounts.
Today I did a bit of residential driving (low to mid speed) and noticed the diff makes quite a lot of noise. It's damn loud too. Sort of high pitched, like a jet engine, and gets louder the faster you go. I had a look under the car and didn't see any spilled oil or any oil on the diff.
Any thoughts on what it could be, and what I should check?
Thanks!
I'm a boost creep...
Joined: Jan 2002
Posts: 15,608
Likes: 8
From: Auckland, New Zealand
I bet you didn't set the backlash and tooth contact like you're supposed to. Read the FSM, search for previous threads on diff swaps or take the diff out and take it to a pro...
Lives on the Forum
Joined: Feb 2001
Posts: 26,664
Likes: 22
From: n
No / bad fluid.
Contact between pinion and ring gear is wrong.
I would drain the fluid to see if it's no good.
Use a clean container, so if the fluid is still good you can put it back in.
I bet there's a lot of crap in there.
-Ted
Contact between pinion and ring gear is wrong.
I would drain the fluid to see if it's no good.
Use a clean container, so if the fluid is still good you can put it back in.
I bet there's a lot of crap in there.
-Ted
