c6 Differential gear change
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Joined: Apr 2020
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From: Central New Jersey
c6 Differential gear change
Hi, I have 2006 base LS2 with M6 and 3.42 gears. I'm looking to change rear gears to 4.11's for better bottom end on street and more responsive 6th gear on highway. ( in 6th car turns 1500 RPM at 65 mph ) Looked into just replacing gears but shops I spoke to mainly do whole differential swaps from either ZIP https://www.zip-corvette.com/06-13-4...l-rebuilt.htmlin Virginia or RPM https://www.rpmtransmissions.com/page45.html in Indiana. Like to hears opinions on which company is preferred or another shop and if whole differential change is better that just changing ring and pinion. I'm old street racer from Brooklyn in 60's -70's, did all work myself including gear changes but just got back into it last year and things seen alot different or are they?
Melting Slicks
Joined: Nov 2007
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From: Pittsburgh PA
St. Jude Donor '10-'11-'12-'13-'14
I changed the rear ratio of my C4 to 3.73's with good results, but have no direct experience with changing them on the C6. The standard answer is that doing this on our cars is much less effective than it was back in the day. First, the LS2 has a broader torque curve than our old engines, so there's more torque at low rpm's to accelerate from a stop. Second, with 6 forward gears in the tranny it's possible to have very low 1st and 2nd gears, while still having high 5th and 6th for good mileage.
Melting Slicks
Joined: Feb 2007
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From: Raleigh Suburbs
Interesting; I ran 4.10's in my M6 LS1 TA for some time - not sure if the ratios are same in the LS2 C6, but prolly are. It was a wallop, in the 1st 4 gears, and evened out, up top. You may consider 3.90's from RPM for best results..
I have not myself changed any gears, however, RPM is now known as one of the biggest shops for rear-ends. I would call them - at the least you could source parts from them..
I have not myself changed any gears, however, RPM is now known as one of the biggest shops for rear-ends. I would call them - at the least you could source parts from them..
Last edited by Hitman227; Jul 18, 2020 at 05:02 PM.
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From: Central New Jersey
well right now car torque doesn't come on until 3500 - 4000 so it's good after that but rolling out from dead stop weak. if racing car always above 4000 so no problem but below that pretty dead. and on highway like I said at 65 to just increase speed have to down shift. car at 1500 at 65 just above idle. Gears are the answer just which way to get them in is the question
Burning Brakes
Joined: Jul 2002
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From: Nova Scotia
I changed my rearend to 3.90s from RPM, one of the first mods I did. Really changed the car. Makes taking off slowly much easier, and makes 6th gear more usable. If I had it over again I might even go with 4.10s
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From: Central New Jersey
yes that's how I feel. Asked about 4.56's they're not available but even those wouldn't be be to big if with 3.42's I'm doing 1500 RPM at 65 MPH, 4.10's from what I read brings it up to 1800 RPM still low, 4.56 may be 2000 RPM. Remember in my 67 chevelle SS big block with 4.10's 60 MPH was at 3000 RPM so 2000 no big deal. what does you 3.90's do at 65 MPH
Drifting
Joined: Jan 2005
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From: Tucson Arizona
St. Jude Donor '08
I did 4:10s in my C6 manual and it was great. Especially when I put in a nasty cam. Those gears help you get moving with better manners. You do have to shift more often obviously in stop and go traffic, so traffic congestion was not fun. And I got the whole assembly from RPM in Indiana. You send them yours as part of the deal. They are a premium outfit.
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From: Central New Jersey
Any body ever try Zip in Virginia they're about $700 less looks like good shop just does vettes around since 1977 also has detailed break in procedure but you don't get the Z06 right and left shafts. are the needed for the street without street slicks
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Burning Brakes
Joined: Jul 2002
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From: Nova Scotia
I think 4.56 would be too much. Remember, these new LS engines work much better at 1800rpm than your old big block chevelle. I can comfortably drive down to about 1600 rpm, which is about what I'm doing at 65mph, but I typically drive a little faster on the highway
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From: Central New Jersey
yes holding steady speed at 65 ,70, car cruises nice , but to increase speed car is dead until you get to minimum 2500 which is at least 85, don't want to be speeding all the time. Same problem I had with KZ1000 bike couldn't be in top gear on highway bike was dead unless doing 80. The cars power range is between 3000 and 6500 RPM. think car is under geared unless you live in Montana or Nevada where you can cruise at 100 or on race circuit. On street if you want lively response pulling out from a roll think or on highway you need bigger gears. 4.10's should be at 1800 RPM at 65 don't think that strain on engine at all. Still waiting to hear if anyone used ZIP differential. https://www.zip-corvette.com/06-13-4...l-rebuilt.html
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From: Central New Jersey
not reluctant but just to around someone or traffic slows for a moment to resume speed back 10mph more have to feature gas peddle and get that low drone. it's like starting in 3rd. Still looking for ZIP opinion.
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From: Central New Jersey
funny I tried that today on highway. to see how 4.56's might feel car has much better response to accelerate to pass or just increase speed after monetary slow down. at 80 mph car was still under 2000 rpm in 6th with 3.42's.. but it doesn't help the doldrums of starting from dead stop. Do I have to pull a hole-shot to take Camry at stop light? Don't understand how all the stock base vette guy's don't see sluggish bottom end? You guy's drinking the EPA kool-aid? 
Instructor
Joined: Dec 2017
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From: Wiltshire, England
I changed to 4.10 this year, in my stock power C6 LS2 M6 Base. Best mod I've made so far. I use my car on the road and for trackdays. 1st to 4th are nice and close, with a larger jump to to 5th. 6th is still a tall gear for high speed cruising. I'm in the UK so I bought Motive Gear crown and pinion and too the diff out and delivered both to one of the few places here with all the tools needed. A complete bearing and shim kit was required too.
This video is just a few days after I fitted the diff with 4.1. Previously, with the 3.42 I'd never used 5th anywhere except the Nurburgring.
This video is just a few days after I fitted the diff with 4.1. Previously, with the 3.42 I'd never used 5th anywhere except the Nurburgring.
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Joined: Apr 2020
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From: Central New Jersey
Nice track footage . All the guy's who went to 4.10's said best mod they did. Going tomorrow to order gears would like to hear any remarks on ZIP also looking into clutch while car apart 30k on car now . any opinoin's?
Intermediate
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