question about expected life of an LSD
#1
I read your email
Thread Starter
question about expected life of an LSD
After many phone calls, I finally found an 85 LSD rear in a bone yard not far from me. I'm gonna go take a look at it this weekend. Good or bad, what should I specifically be looking for? How many miles do these rears live? 50k? 100k? 150k? 200k? What's the max miles I should accept or does it really matter? How will I know if it needs to be rebuilt and what's involved in rebuilding one if I need too? I know that's a lot of questions but I don't wanna get hosed on my purchase. TIA
Last edited by inittab; 04-11-02 at 03:17 PM.
#3
smog nazi destroyer
i donot think that rebuilding them is all that involved.
life all depends on how they were taken care of..
other guys can tell you the proper way to test it.. but try spinning one wheel and see what happens to the other.
life all depends on how they were taken care of..
other guys can tell you the proper way to test it.. but try spinning one wheel and see what happens to the other.
#4
riffraff,
Rebuilding a 3rd member is not a Sunday evening task.
inittab,
Someone told me to check this once, I dont know how good the test is, but my LSD fails it (I think it has to do with the lash): Crawl under the car and try to turn the driveshaft by hand, if there is any free play (where the driveshaft turns but the wheels do not) then you have a problem. There is no good way to test if the LSD is worn out without driving it in a situation where the rear wheels have unequal traction.
Rebuilding a 3rd member is not a Sunday evening task.
inittab,
Someone told me to check this once, I dont know how good the test is, but my LSD fails it (I think it has to do with the lash): Crawl under the car and try to turn the driveshaft by hand, if there is any free play (where the driveshaft turns but the wheels do not) then you have a problem. There is no good way to test if the LSD is worn out without driving it in a situation where the rear wheels have unequal traction.
#6
I read your email
Thread Starter
Well I went ahead and yanked the junkyard axle out today. What a PITA job that was. The doner car had 135k on it and the axle had a lot of surface rust but not much more than my current 82k axle. I couldn't test the play in any of the parts because the brakes were seized tight to the disc's. It's a $150 gamble but I have hopes for this thing. Oh, and BTW, there was a yellow sticker attached to the back that stated that it was a limited slip diff. I suppose my first task will be to get the brakes off and get the thing sandblasted and go from there.
Trending Topics
#12
I read your email
Thread Starter
All sounds of encouragement. That's great!
I didn't grab the master cylinder because, quite frankly, I wouldn't trust it for a mile. My plans include an entire brake system rebuild with the proper master cylinder and braided steel lines too! Can't wait!
I didn't grab the master cylinder because, quite frankly, I wouldn't trust it for a mile. My plans include an entire brake system rebuild with the proper master cylinder and braided steel lines too! Can't wait!
#13
Right near Malloy
iTrader: (28)
Join Date: Dec 1999
Location: Behind a workbench, repairing FC Electronics.
Posts: 7,839
Received 505 Likes
on
342 Posts
It all depends on how the car is driven since the LSD is clutch based in these cars... If nobody has done any tire anahilating burnouts, it'll be good... But if that sucker was kickin up the rubber smoke at every green light, you can bet it's hosed.
#14
Never Follow
iTrader: (18)
You bring up a good point Pele, but My trans am has 125k on it and I do tire melting burnouts just about everywhere (I mean everywhere ) and the LSD still works great. The clutch is a different story...... Hey innitab: I can't wait to see your car after you do all the brake stuff.
#15
I read your email
Thread Starter
Originally posted by 82transam
Hey innitab: I can't wait to see your car after you do all the brake stuff.
Hey innitab: I can't wait to see your car after you do all the brake stuff.
#16
Clutch pak LSD units wear pretty well. They do start to judder/bounce/vibrate as they get older. Also, you can help this with the proper rear end friction modifier. I don't suggest you rebuild one unless you are a good wrencher with lots of tools and experience. Getting the gear lash set right is not too easy to do. If you get it wrong, you trash the ring and pinion really fast. Have a shop or driveline place do it.
#17
I read your email
Thread Starter
Originally posted by etherhuffer
Clutch pak LSD units wear pretty well. They do start to judder/bounce/vibrate as they get older. Also, you can help this with the proper rear end friction modifier. I don't suggest you rebuild one unless you are a good wrencher with lots of tools and experience. Getting the gear lash set right is not too easy to do. If you get it wrong, you trash the ring and pinion really fast. Have a shop or driveline place do it.
Clutch pak LSD units wear pretty well. They do start to judder/bounce/vibrate as they get older. Also, you can help this with the proper rear end friction modifier. I don't suggest you rebuild one unless you are a good wrencher with lots of tools and experience. Getting the gear lash set right is not too easy to do. If you get it wrong, you trash the ring and pinion really fast. Have a shop or driveline place do it.
Can you explain exactly what you mean by "proper rear end friction modifier"? Thanks.
#18
I think Mazdatrix sells lsd friction modifier just for these units. They sell these types of additives at the parts houses. Its mentioned in the technical data of the factory service manual. The main thing is that the unit is going to seem rougher, especially while turning a sharp corner and accelerating at the same time. Don't let it bug you if its working ok.
#19
Rotary Enthusiast
iTrader: (1)
Join Date: Jul 2001
Location: NORTH CAROLINA
Posts: 1,059
Likes: 0
Received 0 Likes
on
0 Posts
I have a lsd for sale on my 84 gsl...take the whole car for 350.00...has engine , interior , lsd...why pay 150 for a lsd when you can have most of the car for 350.00...anyone want it , let me know..cjf
#22
I read your email
Thread Starter
Preventative maintenance?
Okay, I've got the rear stripped of all the brake parts, lines, etc and I've done a wire brushing of it. It's not looking so bad anymore. Now that the rear is in this rather naked state, it seems to be a perfect time to consider maintaining any internal parts, bearings, whatever. My current plan is to sandblast it then do a POR-15 job on it. I purchased POR-15's "Engine Painting Kit". The kit includes everything you need to repaint an engine. My logic being that an axle is more/less like an engine. I'll let you guys know how it comes out. So... should I just paint it, wish for the best, slap it on the car and go? or what? TIA
Okay, I've got the rear stripped of all the brake parts, lines, etc and I've done a wire brushing of it. It's not looking so bad anymore. Now that the rear is in this rather naked state, it seems to be a perfect time to consider maintaining any internal parts, bearings, whatever. My current plan is to sandblast it then do a POR-15 job on it. I purchased POR-15's "Engine Painting Kit". The kit includes everything you need to repaint an engine. My logic being that an axle is more/less like an engine. I'll let you guys know how it comes out. So... should I just paint it, wish for the best, slap it on the car and go? or what? TIA
#23
Nikki-Modder Rex-Rodder
Join Date: Feb 2001
Location: Trying to convince some clown not to put a Holley 600 on his 12a.
Posts: 2,890
Likes: 0
Received 14 Likes
on
6 Posts
Sandblasting is great. But everything has to be sealed up perfectly, because if it's not, you will NEVER get all the blasting medium out, and it will work to destroy bearings in a hurry.
Your other option is removing residual rust by chemical means.
Search for products engineered for marine application if no one here supplies you with a list.
Your other option is removing residual rust by chemical means.
Search for products engineered for marine application if no one here supplies you with a list.
#24
I would do bearings and seals if you have the bucks. Since the third member pops out by itself, you can always replace the lsd alone later. The POR 15 sounds great. I have thought about the Rhino truck bed coatings for under car stuff.
#25
I read your email
Thread Starter
It lives!
I just got the car all put together again and the LSD seems to be fine. It doesn't produce any whining noises and so far appears to work properly. I do notice that when starting out with the front wheels turned I do get a shuttering from the rear. I think this is normal, yes? Right now I'm running 'el cheapo gear oil in it but I have some RedLine MT-90 sitting on the shelf. Below are the before and after pics.