Gen 5 gear ratio change from 3.27 to 3.91? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

CAMVROOM · 05-03-2021, 02:59 PM

I have an A6 Camaro 2014.

What is needed for Gen 5 gear ratio change from 3.27 to 3.91?

I remember reading that for the A6 you have to buy more parts, and it is not just a simple replacement compare to M6?

Can I just change the rear diff or do I have to do change the rear diff + other parts (axle, driveshaft, etc) that attach to the rear diff or basically swapping the entire rear to an SS A8?

I have read that this mod is the best bang for your buck?
For me, if you have to change more than the diff I feel like it looks difficult. What is the price range for labor if needed to be done by someone else? and what is the cost of all the parts?

Thanks, J.

AlanRubin · 05-03-2021, 03:19 PM

IF the 3.91 is from an SS or Manual car:

3.91 Differential
Rear portion of SS/Manual Car driveshaft.
Wheel Bearings
Axle Shafts

The Manual and SS Auto wheel bearings have more splines, and a larger opening
in the bearing. You do not need the whole knuckle, just the bearing assemblies.

Mr_Draco · 05-03-2021, 04:02 PM

You didn't specify engine size, but if yours is the V6, then yes, not only will you have to replace the differential but every part that connects to the differential and gears.

You don't have to buy all these parts new either, just hit up a junk yard. The differential and other parts from any 2010-2014 manual V6 or any 2010-2014 SS (auto or manual) will work. That way you only have to buy the gears new.

sinlinson · 05-04-2021, 07:42 AM

I got an entire 3.91 differential on ebay for $599 plus $75 shipping. Works great and really woke my car up.

TheFlyingBananaSS · 05-04-2021, 11:33 AM

I only changed ring and pinion. Poof all done. Gears were about 500. Labor about 600. Richmond gears. No noise. Beat them up and they are holding fine.

George-CZ · 05-04-2021, 11:49 AM

TheFlyingBananaSS · 05-04-2021, 11:53 AM

I would only change diff if I was go in ng to ZL1. The 1le diff is not as strong as ZL1.

LCPLPunk · 05-04-2021, 07:56 PM

I think I paid about $1100 in parts/labor to go from 3.27 to 3.91...and that included a master rebuild kit...

gunchamp · 05-04-2021, 10:02 PM

I bought a slightly used 391 factory complete rear. Swapped it in, no problem. 391 is the right ratio for thesebcars with an auto

CAMVROOM · 05-05-2021, 01:35 AM

Quote:

Originally Posted by Mr_Draco

You didn't specify engine size, but if yours is the V6, then yes, not only will you have to replace the differential but every part that connects to the differential and gears.

You don't have to buy all these parts new either, just hit up a junk yard. The differential and other parts from any 2010-2014 manual V6 or any 2010-2014 SS (auto or manual) will work. That way you only have to buy the gears new.

I think it would be more work with a manual v6 swap than a SS auto? If the car is an auto trans gear with a manual rear diff + etc, wouldn't you have to program it. How would you shift your gear correctly?

CamaroCracka · 05-05-2021, 10:41 AM

Yes, anytime you change gear ratios in a modern vehicle you have to adjust the ECM.

M6 V6 has the SS diff, but the auto has the 192mm diff. Most of the swaps are pretty easy, but not sure on the auto V6.

Finding 3.91s in good shape is not as easy as it used to be. People are asking as much for factory 3.91s as they are for ZL1 diffs. The best ones came in the Z28 if you can find one wrecked. I did a few years back but those are pretty scarce too.

Mr_Draco · 05-05-2021, 10:46 AM

Quote:

Originally Posted by CAMVROOM

I think it would be more work with a manual v6 swap than a SS auto? If the car is an auto trans gear with a manual rear diff + etc, wouldn't you have to program it. How would you shift your gear correctly?

The manual V6 uses the exact same parts as the SS. This is why you can use either.

You have to get a tune when changing gear ratios. Doesn't matter where the parts came from, if your car is a manual or auto, or what the new ratio is, a tune is required when changing gear ratios.

CAMVROOM · 05-09-2021, 08:05 PM

thanks for everyone here for their inputs.

hammdo · 05-10-2021, 09:12 AM

3.91 for auto is great unless - you go FI - then you'll wish for 3.27s...

-Don

05-03-2021, 02:59 PM	#1
CAMVROOM Drives: CAMARO 2014 Join Date: Dec 2020 Location: MOON Posts: 12	Gen 5 gear ratio change from 3.27 to 3.91? I have an A6 Camaro 2014. What is needed for Gen 5 gear ratio change from 3.27 to 3.91? I remember reading that for the A6 you have to buy more parts, and it is not just a simple replacement compare to M6? Can I just change the rear diff or do I have to do change the rear diff + other parts (axle, driveshaft, etc) that attach to the rear diff or basically swapping the entire rear to an SS A8? I have read that this mod is the best bang for your buck? For me, if you have to change more than the diff I feel like it looks difficult. What is the price range for labor if needed to be done by someone else? and what is the cost of all the parts? Thanks, J.

05-04-2021, 11:33 AM	#5
TheFlyingBananaSS Evil Genius of Chevrolet Drives: 2017 Z06, 2019 XTS, 2013 SS Join Date: Feb 2017 Location: New York Posts: 3,260	I only changed ring and pinion. Poof all done. Gears were about 500. Labor about 600. Richmond gears. No noise. Beat them up and they are holding fine. __________________ GPI SS2 VVT cam, ECS Novi 1500 supercharger, Corsa Extreme, Detroit Speed and BMR suspension, Circle D triple disc, Melling oil pump, LS2 chain tensioner, ATI 10% UD, DSX E85 kit, High Energy coils, BTR springs, LS2 Lifter trays, Titanium retainers, hardened push rods, FIC 1000 injectors, ZL1 pump, Mighty Mouse catch can, AEM gauges, Tial BOV, Richmond 3.91 gears, Custom gauge bezels, Speed Engineering headers, Stainless Works HF cats, DSX Aux pump, 710rwhp on E85.

05-04-2021, 11:49 AM	#6
George-CZ Drives: 2010 2SS LS3 and 1978 STROKER 383 Join Date: Feb 2018 Location: Czech Republic Posts: 1,592	__________________ My life is a constant struggle with Camaro. K&N CAI, Stainless Power longtubes, high flow cats, modified Ragazzon High Performance axle back, Soler Performance ported throttle body, Soler Performance throttle controller, RAM clutch adjuster, modified LS7 clutch kit, Tick Performance billet bearing support, Tick Performance remote bleeder, separate clutch reservoir, BMR trailing arms, BMR toe rods, Pedders Suspension cradle bushing inserts, Control Arm Bushings, Strut tower brace, oil catch can, Hurst T-handle shifter, 20mm wheel spacers, DBA brakes, QTP Cutouts, Dynosteve tune.

05-04-2021, 11:53 AM	#7
TheFlyingBananaSS Evil Genius of Chevrolet Drives: 2017 Z06, 2019 XTS, 2013 SS Join Date: Feb 2017 Location: New York Posts: 3,260	I would only change diff if I was go in ng to ZL1. The 1le diff is not as strong as ZL1. __________________ GPI SS2 VVT cam, ECS Novi 1500 supercharger, Corsa Extreme, Detroit Speed and BMR suspension, Circle D triple disc, Melling oil pump, LS2 chain tensioner, ATI 10% UD, DSX E85 kit, High Energy coils, BTR springs, LS2 Lifter trays, Titanium retainers, hardened push rods, FIC 1000 injectors, ZL1 pump, Mighty Mouse catch can, AEM gauges, Tial BOV, Richmond 3.91 gears, Custom gauge bezels, Speed Engineering headers, Stainless Works HF cats, DSX Aux pump, 710rwhp on E85.

05-04-2021, 07:56 PM	#8
LCPLPunk USA-1 Drives: 2010 Camaro SS L99 Join Date: Jul 2016 Location: Near DC Posts: 1,893 View My Garage	I think I paid about $1100 in parts/labor to go from 3.27 to 3.91...and that included a master rebuild kit... __________________ "A Camaro in the garage is safe, but that's not what Camaros are built for..." R2C CAI / Apex Scoop / VMAX Ported TB / Speed Engineering LTHs / X-pipe / GPI port/rod-mod intake manifold / Circle D 3200 278mm Converter / 3.91 gears / DynoSteve tuned / 1LE Shocks/Struts/Toe Links / ZL1 Rear Sway Bar / Z/28 Trailing arms / Prothane Radius Arm & Subframe Bushings / BMR UCA Bracket, Steering rack bushing / B&M Tranny Cooler / RX Catch Can / Jannetty Tranny Dipstick / 2012+ Heater Hose / 2013+ Rearview Mirror / Fuel rail flip / Drake shifter / Oil Cooler Delete

05-03-2021, 03:19 PM	#2
AlanRubin Banned Drives: 2010 LS Join Date: Feb 2021 Location: Pgh Posts: 411	IF the 3.91 is from an SS or Manual car: 3.91 Differential Rear portion of SS/Manual Car driveshaft. Wheel Bearings Axle Shafts The Manual and SS Auto wheel bearings have more splines, and a larger opening in the bearing. You do not need the whole knuckle, just the bearing assemblies.

05-03-2021, 04:02 PM	#3
Mr_Draco Drives: 2SS/RS Join Date: Sep 2008 Location: Western North Carolina Posts: 7,182	You didn't specify engine size, but if yours is the V6, then yes, not only will you have to replace the differential but every part that connects to the differential and gears. You don't have to buy all these parts new either, just hit up a junk yard. The differential and other parts from any 2010-2014 manual V6 or any 2010-2014 SS (auto or manual) will work. That way you only have to buy the gears new.

05-04-2021, 07:42 AM	#4
sinlinson 2016 2SS Convertible Drives: 2011 Camaro 2SS convertible Join Date: May 2019 Location: NY Posts: 85 View My Garage	I got an entire 3.91 differential on ebay for $599 plus $75 shipping. Works great and really woke my car up.

05-04-2021, 10:02 PM	#9
gunchamp Drives: 15 Camaro SS Join Date: Oct 2018 Location: Mountains of central PA Posts: 1,442	I bought a slightly used 391 factory complete rear. Swapped it in, no problem. 391 is the right ratio for thesebcars with an auto __________________ 15 Camaro SS- GPI max top end, ESS Vortech V3 9psi, ID 1050s, ZL1 pump, JMS bap, Long tubes, Corsa extreme, Circle D pro 5C, 391 rear, DSS carbon drive shaft, poly cradle bushings, tuned by Ted Jannetty and much much more

05-05-2021, 10:41 AM	#11
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,734	Yes, anytime you change gear ratios in a modern vehicle you have to adjust the ECM. M6 V6 has the SS diff, but the auto has the 192mm diff. Most of the swaps are pretty easy, but not sure on the auto V6. Finding 3.91s in good shape is not as easy as it used to be. People are asking as much for factory 3.91s as they are for ZL1 diffs. The best ones came in the Z28 if you can find one wrecked. I did a few years back but those are pretty scarce too. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes.

05-09-2021, 08:05 PM	#13
CAMVROOM Drives: CAMARO 2014 Join Date: Dec 2020 Location: MOON Posts: 12	thanks for everyone here for their inputs.

05-10-2021, 09:12 AM	#14
hammdo 'It's an experiment' Drives: [COTW 2/09/15] '11 GPI LSA SC Z/LE Join Date: May 2014 Location: Dallas TX Posts: 8,694 View My Garage	3.91 for auto is great unless - you go FI - then you'll wish for 3.27s... -Don __________________ 747 RWHP 794 RWTQ "Horsepower sells cars, torque wins races." - Enzo Ferrari See My Build: http://www.camaro5.com/forums/showthread.php?t=385577