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

Black_SS10 · 07-03-2018, 09:26 AM

What is the backlash for polished 3.91 gears supposed to be set at? Thanks!!!

BFASTNOTLAST · 07-03-2018, 10:04 AM

Quote:

Originally Posted by Black_SS10

What is the backlash for polished 3.91 gears supposed to be set at? Thanks!!!

The polish on a gear has nothing to do with backlash. .003 - .005 and call it a day, polished or not.

Black_SS10 · 07-03-2018, 10:33 AM

Quote:

Originally Posted by BFASTNOTLAST

The polish on a gear has nothing to do with backlash. .003 - .005 and call it a day, polished or not.

Thanks. Thats is what I figured. I found the specs for 3.45 gears. I just didnt know if the 3.91 was different. Thanks again!

Black_SS10 · 07-03-2018, 05:55 PM

I researched further. It seems different manufactures have different specs for backlash. I believe I have AAM polished gears, as i bought the diff used and seller doesnt know. They spec .005 to .009 for their 3.91 gears. Right now mine reads at .010, looks truly rebuilt, and with very little if at all any usage.

frankwjr · 07-03-2018, 09:14 PM

when I did my 3.91 upgrade I used the GM 1LE kit which is AAM...using the stock shims(after replacing all of the bearings) the backlash came in at .002.....whisper quiet..

.010 seems at bit high IMHO...and would possibly lead to the rear cluckin when you come off the gas...

good luck OP..ur on the right track!

peace

07-03-2018, 09:26 AM	#1
Black_SS10 SomeguyK Drives: 2010 Black 2SS/RS Join Date: Nov 2014 Location: FL Posts: 1,947	3.91 backlash What is the backlash for polished 3.91 gears supposed to be set at? Thanks!!! __________________ TMS 427, Dart iron Block, Forged assembly, Frankenstien heads, AGP TT 62/62 BB turbo's, AGP/Fore triple fuel system, Tilton clutch, Holley 1 7/8 shorties, Technostalgia tail lights,Oracle, Aeroforce, MGW shifter,Flowmaster, Pegasus subframe bushings,BMR trailing & toe arms,Z28 UCA bushings,Zl1 rear sway bar,Prothane,BMR,Goodridge brake lines,Ridetech HQ coilovers,3.91,Trutrac,billet caps,DSS axles,HE offest,built TR6060,1LE diffuser,Havoc spoiler,SSclones,20in MRR 017, Pirelli P Zero, Nitto NT555RII More to come.

07-03-2018, 05:55 PM	#4
Black_SS10 SomeguyK Drives: 2010 Black 2SS/RS Join Date: Nov 2014 Location: FL Posts: 1,947	I researched further. It seems different manufactures have different specs for backlash. I believe I have AAM polished gears, as i bought the diff used and seller doesnt know. They spec .005 to .009 for their 3.91 gears. Right now mine reads at .010, looks truly rebuilt, and with very little if at all any usage. __________________ TMS 427, Dart iron Block, Forged assembly, Frankenstien heads, AGP TT 62/62 BB turbo's, AGP/Fore triple fuel system, Tilton clutch, Holley 1 7/8 shorties, Technostalgia tail lights,Oracle, Aeroforce, MGW shifter,Flowmaster, Pegasus subframe bushings,BMR trailing & toe arms,Z28 UCA bushings,Zl1 rear sway bar,Prothane,BMR,Goodridge brake lines,Ridetech HQ coilovers,3.91,Trutrac,billet caps,DSS axles,HE offest,built TR6060,1LE diffuser,Havoc spoiler,SSclones,20in MRR 017, Pirelli P Zero, Nitto NT555RII More to come.

07-03-2018, 09:14 PM	#5
frankwjr Drives: 2010 SS 2SS M6 Join Date: Aug 2016 Location: Smithsburg, Md. Posts: 2,445	when I did my 3.91 upgrade I used the GM 1LE kit which is AAM...using the stock shims(after replacing all of the bearings) the backlash came in at .002.....whisper quiet.. .010 seems at bit high IMHO...and would possibly lead to the rear cluckin when you come off the gas... good luck OP..ur on the right track! peace __________________ 2010 SS 2SS M6 - Tune by RDP dynoSteve!(Woot) - Daily Driver - *150K!* - All work by me...