Gears & Axles - just bought a set of Motive 3.90's

I have only had the car for 3 days and already have the rear end tore down. The car only has 23K miles on it. I noticed a whine in the rear shortly after I bought it during the drive home. I jacked the car up and started from the front back changing fluids filters etc...When I got to the rearend there was a lot of shavings on the magnet and the edges of the teeth on the ring gear felt sharp. So I tore it down. I bought the 3.90's. I also noticed the car has no front sway bar. The place I bought it from is paying for a BMR sway bar, I went ahead and ordered the matching rear. Now it sounds like they are going to be paying for a ring and pinion. I bought the car on Ebay and they are wanting me to leave positive feedback, which I have not done yet, looks like they are going to dishing out some more money. Oh and car is a MN6

Its a one owner car too, and looks brand new. I guess someone decided to do some drag racing before they got rid of it.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0027.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0026.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0038.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0041.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0043.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0040.jpg

let me know how you like the gears. I've been debating 3.90s for a minute now.

let me know how you like the gears. I've been debating 3.90s for a minute now.

same.

Not to sound too smartass, but what the hell is MN6?

RPO code for what gears are inside the t56.

MN6 vs MN12

1st Gear 2.66 vs 2.97
2nd Gear 1.78 vs 2.07
3rd Gear 1.30 vs 1.43
4th Gear ----1.00----
5th Gear 0.74 vs 0.84
6th Gear 0.50 vs 0.56

I believe certain corvettes and the GTOs got the mn12?

Not to sound too smartass, but what the hell is MN6?

RPO code for T56

Well it looks like I am going to get another $300 out of them to pay for the ring pinion and install kit. I am glad they are making it right. I went ahead and pulled the rear end out to make it easier on me setting the gears up. Better then doing it on my back. One of these days I will have a lift.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0048.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0046.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0047.jpg

Nice car man. How much did you pay? I have 3.90 in my Moser 9 and they whine now... I think it just really depends on the set and how they are put in.

Nice car man. How much did you pay? I have 3.90 in my Moser 9 and they whine now... I think it just really depends on the set and how they are put in.

Payed $14900.00 for the car. I dont plan on drag racing, I just want a nice street/weekend car so hopefully the old 7.5 will hold up. I noticed that the axel tubes are pressed into the center section and are held in with some kind of rivet or pin. I am pretty sure the center section is cast steel and can be welded so I am thinking about welding the tubes to the center section. Try to make it a little stronger.

weld the tubes and paint it while its out.

weld the tubes and paint it while its out.

Thats what I am going to do. Has anyone tryed to triangulate the housing to the tubes? I was thinking about welding some angle to the center section around the pinion area then down to the tubes. It would have to help the tubes from flexing. May not do anything to help either.....

RPO code for T56

ahh gotcha. I knew what the 12 was.

Yep,weld the tubes and get a TA Performance girdle diff cover.

Welded the tubes this morning before I went to work. Cranked my little 120 Mig all the way up. Didnt weld to bad, seems like it penetrated pretty good. It got pretty hot too, there was oil seeping out from the rivets. I will weld around those tonight to seal them off. I will get some pictures too.

Got the gears yesterday. I finished welding on the tubes and the rivets then put a coat of satin rustoleum. Looks pretty good so far. I plan on starting the setup on the gears this weekend. A few more pics for ya.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0053.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0054.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0056.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0057.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0058.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0059.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0060.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0061.jpg

Be prepared for some gear whine with those motives... Nice car btw!!

Be prepared for some gear whine with those motives... Nice car btw!!

I hope not, I am going to take my time and try to get a good patern on them. If I do they should not make any noise. We shall see...

I had a thirdgen that I was restoring about this time last year. I scraped it, to big a project. Anyway I bought all new prothane bushings for the whole car. I sold all of them accept the rear LCA bushings. Just so happens they are the same on the 4thgen so I went ahead and put them on tonight. I also cleaned and painted my wheel wells.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0064.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0063.jpg

Man I am pissed. I spent all day setting these danm gears up and they sound like shit. I never really got a good pattern on the coast side but the drive side is dead in the middle. The factory pinion shim was a .032, I have it at .037 right now. I used a pinion depth tool, checked the depth with the factory shim in and I was within .001 of the depth writen on the pinion. But the pattern said the pinion neede to come up so I added .005. I have some pictures of the pattern but I am too tired and getting ready to go to bed. I put 9 miles on the car so shurley they arent hurt. What I am thinking I might do is knock the pinion back out and take the .005 out and try it with the factory .032. I am thinking these gears are shit I am not going to be able to get the noise out. Any ideas? anybody else set these up?

Back lash is .009

looking good,nice work so far



I had a thirdgen that I was restoring about this time last year. I scraped it, to big a project. Anyway I bought all new prothane bushings for the whole car. I sold all of them accept the rear LCA bushings. Just so happens they are the same on the 4thgen so I went ahead and put them on tonight. I also cleaned and painted my wheel wells.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0064.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/IMAG0063.jpg

Man I am pissed. I spent all day setting these danm gears up and they sound like shit. I never really got a good pattern on the coast side but the drive side is dead in the middle. The factory pinion shim was a .032, I have it at .037 right now. I used a pinion depth tool, checked the depth with the factory shim in and I was within .001 of the depth writen on the pinion. But the pattern said the pinion neede to come up so I added .005. I have some pictures of the pattern but I am too tired and getting ready to go to bed. I put 9 miles on the car so shurley they arent hurt. What I am thinking I might do is knock the pinion back out and take the .005 out and try it with the factory .032. I am thinking these gears are shit I am not going to be able to get the noise out. Any ideas? anybody else set these up?

Back lash is .009

Told ya so lol

Told ya so lol



I knew you were going to say that :mad:

Here are some pictures of the pattern if anyone that knows anything about setting up gears wants to take a look.

This first picture is the drive side right now.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/CIMG5315.jpg

This is the coast side with the pinion too close, I didnt get a picture of the coast side with the pinion depth I have right now, but it seemed like it changed very little no matter what we did. It did center up on the tooth a little better with the depth I have righ now, but stayed towards the toe.

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/CIMG5314.jpg

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/CIMG5316.jpg

Getting ready to go back in the car

http://i105.photobucket.com/albums/m232/tapyz250/Camaro%20parts/CIMG5317.jpg

How bad is the noise? Is it only making noise on decel or all the time? Wish I could help ya more, but I have never set up a set of gears... I know the previous owner of my car tried 3 different sets of motives and they all made noise. They are a very strong set of gears, but noisy... From what I have herd the yukon gears or gm gears are quiet.

How bad is the noise? Is it only making noise on decel or all the time? Wish I could help ya more, but I have never set up a set of gears... I know the previous owner of my car tried 3 different sets of motives and they all made noise. They are a very strong set of gears, but noisy... From what I have herd the yukon gears or gm gears are quiet.

They are pretty much noisy all the time.

They are pretty much noisy all the time.
Mine were just bought and installed too, do you think we got a bad batch or is this the way it is? After seeing reading your history I don't feel bad about calling Jaws Gears back, I specifically asked about this noise issue and they said Motive was the next best to AAM (GM). If they will consider warranty, I guess I am looking at 3:73s. Les>>>

Thanks for taking the time to photo the process

It makes for interesting reading and the photos are far better than the shop manual provides

Give a Shop that builds rear ends a call

If they are nice guys they'll perhaps make a few suggestions

Bon

There is something wrong with these gears. I tore the car back down today. And moved everything, I made the backlash way wide on purpose and still could not really get a change in the pattern on the coast side. The coast side is heavy toe so I made the backlash wide to see if i could move it towards the heel and it wouldnt go. That was just an experiment. I started taking the pinion back down from .037 to .034 to .032 checking it everytime. I ended up running it at .032 to see if it would be any better. It seemed to be a little better on accel but decel was the same. I am not dealing with crap, I am going to send them back to Summitt and I am going to order the GM 4.10's.

After this second drive I knew was going to be pulling them back out and sending them back, so I let her have it. I love the way they felt but I think 4.10.s would be even better.

Mine were just bought and installed too, do you think we got a bad batch or is this the way it is? After seeing reading your history I don't feel bad about calling Jaws Gears back, I specifically asked about this noise issue and they said Motive was the next best to AAM (GM). If they will consider warranty, I guess I am looking at 3:73s. Les>>>

I guess you had a shop put yours in? Did they say they had a hard time with them? Why 3.73's you may be disapointed with them after driving with the 3.90. I am thinking 4.10. My car is a weekend car so I wont be driving it much.

shouldnt worry as much about toe - heal pattern(this is usually housing alignment),, what you really need to look at is the face to flank pattern

I tried 2 sets of Motive 342's, both sets were noisy, 1 more than the other. Both were unacceptable for a street car. Same shop installed some Yukons, and they are as quiet as the factories.

Just got off the phone with Randys Ring and Pinion. They can’t guarantee that the Yukons will be quiet but they said they never get them sent back for being noisy. But they can guarantee the GM or AAM gears to be quiet. So I have a set of GM 4.10,s with a crush collar eliminator shim kit coming.

I guess you had a shop put yours in? Did they say they had a hard time with them? Why 3.73's you may be disapointed with them after driving with the 3.90. I am thinking 4.10. My car is a weekend car so I wont be driving it much.
No, no trouble installing them at all. I called him today and he said he would try another gear if thats what I want but in his experiance the F-body transferes noise through the suspension. He says that even a GM gear will have some noise as the original 3:42 did, and its pattern was good! As for the 3:90, I just want to play and light up the tires, its a little tight 1st through 4th but maybe I just need to give it a chance? I have hesitated with the 3:73 from the start based on all read here, so I guess I have to live with it! Any happy M6rs out there using a 3:73, please let me know, I don't want to leave things too long!! Thanks, Les>>>

I had a shop install some 3.90 Motive's for me. They have a touch of whine on decel but not bad. Did you get the red (performance) or blue box motives? I heard the blue box are more prone to whine.

I had a shop install some 3.90 Motive's for me. They have a touch of whine on decel but not bad. Did you get the red (performance) or blue box motives? I heard the blue box are more prone to whine.

They only make the 3.90 in the orange box perfprmance gear. They are the ones that whine. The blue box gears are not the perfprmance gears. I think they are junk and after I get the oem gears in I will know for sure.

I guess everyones version of noise is different, I am pretty picky.

Yup AAM are the way to go. Lmperformance.com has them at a good deal if you haven't bought them yet.

Yup AAM are the way to go. Lmperformance.com has them at a good deal if you haven't bought them yet.

I bought them local and will have them tomorrow. Just reading up on having to grind the block on the torsen. It was a little tight on the 3.90's. So I knew it would get hairy with the 4.10's.

Really I've never heard of that? Link?

I bought them local and will have them tomorrow. Just reading up on having to grind the block on the torsen. It was a little tight on the 3.90's. So I knew it would get hairy with the 4.10's.

what block??

what block??

The 4.10 ring gear is taller and will not allow you to get the torsen paddle block in that holds the axels out and keeps the C clips in. SLP made a paddle that was split in half to be used with a 4.10 gear set. All you have to do is grind on the paddle you have to get it to slide in. It does not hurt to grind on this because all it does is keep the axels pushed out.



http://www.ls1tech.com/forums/gears-axles/1311929-modifying-torsen-paddle-pics.html

The 4.10 ring gear is taller and will not allow you to get the torsen paddle block in that holds the axels out and keeps the C clips in. SLP made a paddle that was split in half to be used with a 4.10 gear set. All you have to do is grind on the paddle you have to get it to slide in. It does not hurt to grind on this because all it does is keep the axels pushed out.



http://www.ls1tech.com/forums/gears-axles/1311929-modifying-torsen-paddle-pics.html

interesting i didnt know that about the torsen

Ok started over. Here are some pictures of the pattern I got with the 4.10. They did setup a lot better then the Motives did. You can see the factory laping marks real well on these gears, they seemed to ride towards the top of the tooth. So, that what I shot for on my pattern. I started out with the factory shim which is .032 then went to .030. Final backlash is .006.

Drive side at .032 back lash .008

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5339.jpg

Coast side at .032 back lash .008

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5340.jpg

Drive at .030 back lash at .006

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5349.jpg

Coast at .030 back lash at .006

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5348.jpg

I think they look pretty good but want some more opinions before I stick it back in the car.

Here are some pics of the process of changing pinion shims, installing ring gear etc..

Instaling pinion bearing and shim

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5335.jpg

Removing pinon bearing and shim.

Installing ring gear using the old ring gear as a shim and to protect the teeth on the mew one

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5329.jpg

Ground down Torsen block to clear ring gear

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5332.jpg

After sleeping on it, I thnk the pattern was better at .032. I just read the AAM manual and the back lash can be ast tight as .004. My best pattern was at .032 on the pinion and .005 backlash. I thought .005 was to tight so I took it apart. That was with all the factory shims in the the same places they were from the factory. I guess that would make sense. So its going back together with the factory shims and I am going to run it.

when checking the backlash,, make sure to rattle the ring gear back and forth (put a box end wrench on one of the ring-gear bolts and rattle it) and give it a tap side to side ,, and you will see your backlash change up to a few thousandth's

also when checking pinion bearing pre-load give the pinion a tap from both ends and re-adj your pre-load

I have 3.90 motives and their dead quiet. The trick is to get the BL down to a minimun. I like to try to get it to the 6-8 thou range. The only problem with noise I have ever had is with richmond gears. The 7.5 is very finickey. The pattern they like looks horrible. I don't use a pinion depth setting on these rears because it never seems to get me a quiet rear. I love my 3.90's, I needed them to get threw the 1/4 as I was hitting the limiter with 4.10's. They picked me up 2mph.

I have 3.90 motives and their dead quiet. The trick is to get the BL down to a minimun. I like to try to get it to the 6-8 thou range. The only problem with noise I have ever had is with richmond gears. The 7.5 is very finickey. The pattern they like looks horrible. I don't use a pinion depth setting on these rears because it never seems to get me a quiet rear. I love my 3.90's, I needed them to get threw the 1/4 as I was hitting the limiter with 4.10's. They picked me up 2mph.

How long did it take you to figure that out? The backlash they recomend is .007-.008 maybe if I would have tightend them they would have calmed down. For every five guys that say thier 3.90's make noise there is one that says they are quiet.

Going by the pattern I had that would have made since to tighten up the back lash. But, I had it at about .008 I think. I am going to run the 4.10's tight at .005.

What gear are you in hitting the limiter with 4.10's in the 1/4?

In regards to welding up axle tubes. I have a friend with a chassis shop who does a lot of rear end narrowing and housing work. I was at his shop when he narrowed a 9" for my old racecar and he showed me how much the axle tubes moved while welding on them.

He installs a centering device in the housing that has a billet bar and bushing that extends out to the axle bearing area. When he started welding the ladder bar brackets on the axle tubes, you could watch the axle tubes move off of center.

He said after you weld on axle tubes, it almost always distorts them off center, then you have to do a truing process with heat to re-center the tubes properly.

Food for thought when you are welding on axle tubes.

I have run the 4.10 with as little as .004 anytighter than that seems to get a little bind. These rears are the hardest I've ever set up to get quiet and most of the time the pattern don't look like it should for them to run quiet. Did you look at the pattern for the 3.42's? If not slap them back in there and look at it.....it'll look like crap....then duplicate that pattern with your other gears and you'll have a quiet 7.5.

I have run the 4.10 with as little as .004 anytighter than that seems to get a little bind. These rears are the hardest I've ever set up to get quiet and most of the time the pattern don't look like it should for them to run quiet. Did you look at the pattern for the 3.42's? If not slap them back in there and look at it.....it'll look like crap....then duplicate that pattern with your other gears and you'll have a quiet 7.5.

The 3.42's were toast so I didnt check the pattern.

In regards to welding up axle tubes. I have a friend with a chassis shop who does a lot of rear end narrowing and housing work. I was at his shop when he narrowed a 9" for my old racecar and he showed me how much the axle tubes moved while welding on them.

He installs a centering device in the housing that has a billet bar and bushing that extends out to the axle bearing area. When he started welding the ladder bar brackets on the axle tubes, you could watch the axle tubes move off of center.

He said after you weld on axle tubes, it almost always distorts them off center, then you have to do a truing process with heat to re-center the tubes properly.

Food for thought when you are welding on axle tubes.

When I welded the tubes, I started at 12 oclock with about a 1/2" weld. then fliped it to 6 oclock 1/2" weld. Then the same for 3 and 9 oclock. Then welded all the way around. Tryed to keep it from pulling the tubes. I hope it worked....

Ok, put it back to .032 on the pinion shim and got the back lash down to .004 per the AAM instructions. I might add a .001 to the passenger side to try to get a little bit more back lash .004 just sounds tight. But I think the pattern looks great. I dont think it could get any better. Check it out.

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5351.jpg

http://i105.photobucket.com/albums/m232/tapyz250/CIMG5350.jpg

That is as good as it gets for sure.

Good thread. That's one of the things I can't do is setup a rear end.

Good thread. That's one of the things I can't do is setup a rear end.

It is a pain in the ass. The 7.5 is a bitch to setup. It seems like .001 to .002 of an inch makes a big difference on the pattern as far as changing back lash and pinion depth. On these gears there was a pretty big differnece in the pattern. With .030 the pattern was to far towards the face of the teeth and .032 moved it back towards the flank or root but may still be a little to far in. I didnt try .031. I have setup a few 8.5 10 bolts and they are more forgiving.

Anyway, drove the car last night and it sounds pretty good. I might have a little noise around 55 mph when I let off the gas on decel. I dont know if its worth tearing it back down for. If I did I dont even know what I would do to make it better. You have to really be listening to hear it. It is 1000 times better then the Motive gears.

Ended up running it just like it shows above .032 pinion and dead on .004 back lash.

good job, AAM good gear just must be set up tight
Johnny

I just found this site. This guy has some good info on making a quiet 7.5. He has me wanting to take mine back apart, becasue I am just that anal. He says that the pattern at the bottom or root of the tooth should not be cut off abrubtly which I have on my pattern. Could be why I still have a small noise.

http://greenfries.info/rear_gear.htm

Update, I ended up going .031 on the pinion shim and with .004 BL. The 4.10's are quiet. But, man they are low, I think a little to low for my taste. I will drive it like this for a while. Then later I may give the 3.90 another shot. I have learned a lot and feel like I can read the patterns better. I am confident that I can set the 3.90's up and get them quiet.