3.91 swap commencing - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Black-Out · 03-02-2014, 10:56 AM

Started on it yesterday.

Cradle out in a bit under 2hrs (haven't done it before, so I took my time!).

Dropped the pumpkin, and drained the oil. OMFG!!! Looked like half & half silver and black spray paint. And there couldn't have been more than 1/2 a liter! This is rather disturbing, as I'd had it in to GM about a year ago for their recall/TSB on noisy diff while cornering. Looks like they failed to fill it properly.

Anyhow...

Doing my Pfadt arms, and Energy bushings, as well as the GM 3.91's all at the same time. Guess I'll do the GM splash guards too! I'm there. Why not.

Would have had the pinion dropped out already, but went to 'apply' my 3 jaw puller - THEN remembered that I'd blown the threads out of it the last time I used it and forgot to get a new one...

(double sucks, as I work at a tool store, and am about to go buy one retail!)

Since everyone likes pics...

Black-Out · 03-03-2014, 09:40 PM

Well.. this has been fun. Oh wait. No, no it hasn't.

The side bearings have a distinct browny smear in the cups (where the rollers contact), so there has been some not-so-nice heating going on. Bear in mind I only have ~7500 miles on the car.

I'm guessing the lack-o-lube was from when I had the car in at the GM dealer to have the TSB on the rear end taken care of (chatter on cornering) about a year or so ago. Of course, having done all the above myself, I have no way of proving it to them.

So, now I get to order up a bunch of new bearings, and eat the cost. Glad I'm doing this myself, and not having to pay someone yet MORE money for labour.

Anyone have a cross reference from the GM #'s for the bearings and seals to some SKF, Timken, etc?

Black-Out · 03-03-2014, 11:23 PM

Great. This just keeps getting better. not.

I pressed the pinion shaft out in my press. I heard 'clunk-clunk'. Wait. Clunk clunk? Two clunk? Oh crap.

See all the dents in the bearing? That's from the chunk of what appears to be a broken bit of side shim material from the factory!!!
It's been bouncing around in there for all these years. Surprised it hasn't done even more damage.
Really wishing my whole diff had just blown up, then GM could have found all this.

Jpb972 · 03-04-2014, 06:06 AM

Did you do the cradle bushings yet? I'm curious as to how much of a headache it's going to be when I do mine.

Black-Out · 03-04-2014, 10:12 AM

Poked at them a bit - they look easy enough since it's a "plastic" sleeve that's pressed into the cradle (vs the steel sleeves of days gone by).
Gotta get the actual diff issues sorted before I even bother looking at them for real.

EM1/SS · 03-04-2014, 03:15 PM

I did mine a few years ago. They are a metal sleeve and a real B*tch to get out.

Jpb972 · 03-04-2014, 06:06 PM

Quote:

Originally Posted by EM1/SS

I did mine a few years ago. They are a metal sleeve and a real B*tch to get out.

That's what I was afraid of.

LS3 SS · 03-04-2014, 06:29 PM

If you have a sawzall or a torch, you can get the cradle bushings out fairly easy. Just takes a little time and patience.

Black-Out · 03-04-2014, 08:29 PM

Maybe early cars ('10) were metal sleeves? Mine are plastic of some sort!

EM1/SS · 03-05-2014, 01:46 PM

My mistake, I was talking about the rearend bushings, the ones on the rear cradle are plastic.

Jpb972 · 03-05-2014, 04:31 PM

Quote:

Originally Posted by EM1/SS

My mistake, I was talking about the rearend bushings, the ones on the rear cradle are plastic.

bobzilla · 03-05-2014, 10:19 PM

Please update once the gear goes in. I'm curious to see how it improved the driving. I have been thinking about installing the 3.91 in mine but can't figure it out if it's worth it or not.

JCunningham · 03-05-2014, 10:27 PM

its worth it. its like adding 50ftlbs of torque. it feels like a 13% increase in torque over the SS M6 3.45 gears and 20% over SS A6 3.27 gears. i only lost 2mpg

maddoggyusa · 03-05-2014, 10:58 PM

has anybody figured out how to recalibrate the speedo?

03-02-2014, 10:56 AM	#1
Black-Out Drives: himself insane Join Date: Jun 2012 Location: Delta, BC, Canada Posts: 192 View My Garage	3.91 swap commencing Started on it yesterday. Cradle out in a bit under 2hrs (haven't done it before, so I took my time!). Dropped the pumpkin, and drained the oil. OMFG!!! Looked like half & half silver and black spray paint. And there couldn't have been more than 1/2 a liter! This is rather disturbing, as I'd had it in to GM about a year ago for their recall/TSB on noisy diff while cornering. Looks like they failed to fill it properly. Anyhow... Doing my Pfadt arms, and Energy bushings, as well as the GM 3.91's all at the same time. Guess I'll do the GM splash guards too! I'm there. Why not. Would have had the pinion dropped out already, but went to 'apply' my 3 jaw puller - THEN remembered that I'd blown the threads out of it the last time I used it and forgot to get a new one... (double sucks, as I work at a tool store, and am about to go buy one retail!) Since everyone likes pics... Attached Images __________________ {sold} -- 2011 Camaro 2SS/RS - Black on Black. Kooks catted LT's, CAI, Accell 9070c ceramic wires, Barton shifter, custom catback w/Dynomax VT's, quad tips, Pfadt springs/sway bars/trailing arms, Diablosport tuner {Lew tune}, 3.91 gear's, Energy cradle bushings.

03-03-2014, 09:40 PM	#2
Black-Out Drives: himself insane Join Date: Jun 2012 Location: Delta, BC, Canada Posts: 192 View My Garage	Well.. this has been fun. Oh wait. No, no it hasn't. The side bearings have a distinct browny smear in the cups (where the rollers contact), so there has been some not-so-nice heating going on. Bear in mind I only have ~7500 miles on the car. I'm guessing the lack-o-lube was from when I had the car in at the GM dealer to have the TSB on the rear end taken care of (chatter on cornering) about a year or so ago. Of course, having done all the above myself, I have no way of proving it to them. So, now I get to order up a bunch of new bearings, and eat the cost. Glad I'm doing this myself, and not having to pay someone yet MORE money for labour. Anyone have a cross reference from the GM #'s for the bearings and seals to some SKF, Timken, etc? __________________ {sold} -- 2011 Camaro 2SS/RS - Black on Black. Kooks catted LT's, CAI, Accell 9070c ceramic wires, Barton shifter, custom catback w/Dynomax VT's, quad tips, Pfadt springs/sway bars/trailing arms, Diablosport tuner {Lew tune}, 3.91 gear's, Energy cradle bushings. Last edited by Black-Out; 03-03-2014 at 11:25 PM.

03-03-2014, 11:23 PM	#3
Black-Out Drives: himself insane Join Date: Jun 2012 Location: Delta, BC, Canada Posts: 192 View My Garage	Great. This just keeps getting better. not. I pressed the pinion shaft out in my press. I heard 'clunk-clunk'. Wait. Clunk clunk? Two clunk? Oh crap. See all the dents in the bearing? That's from the chunk of what appears to be a broken bit of side shim material from the factory!!! It's been bouncing around in there for all these years. Surprised it hasn't done even more damage. Really wishing my whole diff had just blown up, then GM could have found all this. Attached Images __________________ {sold} -- 2011 Camaro 2SS/RS - Black on Black. Kooks catted LT's, CAI, Accell 9070c ceramic wires, Barton shifter, custom catback w/Dynomax VT's, quad tips, Pfadt springs/sway bars/trailing arms, Diablosport tuner {Lew tune}, 3.91 gear's, Energy cradle bushings.

03-04-2014, 06:06 AM	#4
Jpb972 Drives: 2011 2SS/RS Join Date: Oct 2013 Location: South jersey Posts: 584 View My Garage	Did you do the cradle bushings yet? I'm curious as to how much of a headache it's going to be when I do mine. __________________

03-04-2014, 03:15 PM	#6
EM1/SS Drives: 11 2SS/RS M6 vert Join Date: Dec 2010 Location: NSB, FL Posts: 705	I did mine a few years ago. They are a metal sleeve and a real B*tch to get out. __________________ LSA supercharger, Borla S-Type cat back, BMR/ Pedders Suspension, Kooks stepped LT's, GM 3.91, and RDP tune.

03-04-2014, 10:12 AM	#5
Black-Out Drives: himself insane Join Date: Jun 2012 Location: Delta, BC, Canada Posts: 192 View My Garage	Poked at them a bit - they look easy enough since it's a "plastic" sleeve that's pressed into the cradle (vs the steel sleeves of days gone by). Gotta get the actual diff issues sorted before I even bother looking at them for real.

03-04-2014, 06:29 PM	#8
LS3 SS Drives: 2010 Cyber Grey Camaro SS (LS3) Join Date: Mar 2010 Location: Clarksville TN Posts: 2,275	If you have a sawzall or a torch, you can get the cradle bushings out fairly easy. Just takes a little time and patience. __________________ GPI SS3 Cam / PRC 255 heads / Forged 376ci bottom / Fore level 2 fuel system / D1SC ProCharger on 12lbs / Alky control dual nozzle / 770 whp / 649 wtq tuned by Ryan Stevens at GPI

03-04-2014, 08:29 PM	#9
Black-Out Drives: himself insane Join Date: Jun 2012 Location: Delta, BC, Canada Posts: 192 View My Garage	Maybe early cars ('10) were metal sleeves? Mine are plastic of some sort! __________________ {sold} -- 2011 Camaro 2SS/RS - Black on Black. Kooks catted LT's, CAI, Accell 9070c ceramic wires, Barton shifter, custom catback w/Dynomax VT's, quad tips, Pfadt springs/sway bars/trailing arms, Diablosport tuner {Lew tune}, 3.91 gear's, Energy cradle bushings.

03-05-2014, 01:46 PM	#10
EM1/SS Drives: 11 2SS/RS M6 vert Join Date: Dec 2010 Location: NSB, FL Posts: 705	My mistake, I was talking about the rearend bushings, the ones on the rear cradle are plastic. __________________ LSA supercharger, Borla S-Type cat back, BMR/ Pedders Suspension, Kooks stepped LT's, GM 3.91, and RDP tune.

03-05-2014, 10:19 PM	#12
bobzilla Drives: 720RWHP Join Date: Mar 2014 Location: LaPorte, TX Posts: 22	Please update once the gear goes in. I'm curious to see how it improved the driving. I have been thinking about installing the 3.91 in mine but can't figure it out if it's worth it or not.

03-05-2014, 10:27 PM	#13
JCunningham Drives: 2017 2SS M6 Join Date: Jun 2013 Location: WNY Posts: 7,070	its worth it. its like adding 50ftlbs of torque. it feels like a 13% increase in torque over the SS M6 3.45 gears and 20% over SS A6 3.27 gears. i only lost 2mpg __________________ real ZL1 wheels and brakes, 285/305 Michelin Pilot Super Sports, Pray ported Intake manifold, Soler Throttle Body, Rotofab intake, EFI Tuning Flex fuel kit, full American Racing Headers Exhaust, 1 7/8" w/ cats H pipe and mufflers. Full 1LE suspension, with BMR adjustable sway bars and links, GM aluminum cradle bushings, Hurst shifter with lighter reverse spring, TWM shifter knob, Tick level 1 transmission. I should have bought a ZL1

03-05-2014, 10:58 PM	#14
maddoggyusa Drives: 2013 Camaro Dusk 2SS/6 Join Date: Sep 2013 Location: New Jersey Posts: 1,586	has anybody figured out how to recalibrate the speedo?