3.91 gears

[blazzin1]

Originally Posted by ssmike

What does the crush sleeve look like? I don't think my gear set came with one. Got it from Maureen.

My gear set from Maureen was missing it also, she had to order one for me. It is also called a pinion spacer.

[ssmike]

Originally Posted by blazzin1

My gear set from Maureen was missing it also, she had to order one for me. It is also called a pinion spacer.

Did she charge extra for it or was it supposed to be included with the gear set?

[stikSS]

In the gear set you shouldve got a package of pinion bolts and the sleeve is with that.

Its fairly small... the picture above is very blown up compared to the actual size... but it gives you the idea of what it looks like

Sent from Apple sued Galaxy Note 2

[ssmike]

Originally Posted by stikSS

In the gear set you shouldve got a package of pinion bolts and the sleeve is with that.

Its fairly small... the picture above is very blown up compared to the actual size... but it gives you the idea of what it looks like

Sent from Apple sued Galaxy Note 2

Yep, it's in there! Thanks!

[stikSS]

So... a short write up.

We started the swap Friday afternoon removing the carrier from the car.... make sure you have a 18mm socket because 85% of the bolts in the rear of these cars are that. The removal was basically very easy. If you have an extra set of hands, I would say you can have the carrier out in less than an hour and a half. Depending on how you've driven your car or the mileage... the existing bearings and seals will probably work for you, as long as you don't damage anything in the removal of your axles or the gears. If you have access to a press then basically its a pull out, unbolt the pinion and put back together kinda job. I know that sounds ridiculous, but I've never messed with gears before and after getting a small lesson from my mechanic, I wouldn't be afraid to do another set right now on my own. I would still recommend a mechanic with differential knowledge to help or teach you as you go if you're looking to do the install yourself, but none the less it has been one of the easiest mods on my car so far. Once the gears were in, we started the install of the carrier and axles. The re-install took maybe an hour... and it was ready to roll. I put Royal Purple gear oil back in... it already has the additive you need in the oil.

Now... I made a 5 or 6 mile loop around the block, making left and right turns... No noise at all, all 6 gears felt great, I can tell the greatest difference in 4th -6th gear, where I use to down shift to take off from that speed... now its just step on the pedal and it picks up alot faster! After the trip around the block, I got back under the car to check for any leaks and let it cool down... everything looked perfect, and then I jumped in and drove about 25 miles... everything just like it was from the factory.

1st gear is still very usable... I know alot of people are asking if you can just take off in 2nd gear... You can... but you have to ride the clutch to do it... I tried it last night as I was curious myself. Its possible, but not realistic if you want to keep the clutch.

My car is cammed with a texas speed 231/236... I had alot of cam surge in all the gears at a low speed... but with the gear, all that is gone... the higher rpms in each gear basically eliminated all that. That in itself is well worth the 248 I paid. So if you're looking to do the swap... It's very worth it, cheap, and pays off great in the end.

One side note...... my speedo is about 6 mph off... I had my wife drive next to me last night and she was at 56 and I was showing 62.

[67motorcat]

.............:party0048:.............

[fldrummer]

^I've found the speedometer error to be a percentage error, not a set MPH error. Basically, the faster you go, the more off it is. Your odometer will rack up miles faster than it should also. You have to fix it in the tune.

[SSOOCH]

Originally Posted by 67motorcat

I'm sure my friend will post up when he finds this thread.

The install wasn't bad at all.The GM gears comes with ring gear bolts and a new crush sleeve.We didn't need any additional parts or a "install" kit.
The diff cover seal is a reusable O ring gasket to boot!

There were no shims to be found,just a machined spacer on each side and it went rite back in no problem.We reused the bearings as they were fine.

Just need a bearing puller and a press to press the bearing on the new pinion.
That's the only special tools really needed.Torqued up the new crush sleeve with the pinion nut till it bottomed out and viola,it spun perfect,then pinned it.

I was amazed the contact pattern was absolutely perfect also reusing everything put back in it's original location.

I'll bet this has a lot to do with the gears being OEM and the superior close CNC machining tolerances of the housing.

If the bearings were to be changed there might be more steps to get it rite,can't comment on that.

Back in the day it was a nightmare getting the correct pattern with aftermarket gears in the 10 or 12 bolts rear ends.

Don't know if we got lucky or what, but this was probably the easiest gear swap on the planet.

The GM 3.91 gears are definitely making there way into my car very soon

Did you have set the backlash? How was the mesh?

This sounds awesome that it was that easy!!

[DaFisch]

I am a noob to this all so can someone help me ^.^
I am looking at swapping out my gears for these and was wondering if someone could link everything I need. Also, did you take it the a dealer to have it swapped or a shop. Also, did you have to correct the spedometer and or tune it once you were done? Thanks guys!

[1 Sic SS]

Hey, where do you find these gears for 220

[JMT]

Have the kit and ready to change gears. Anyone notice gear whine afterwards?