anybody have any experience converting an A4 95 Z28 to a 6pack using a viper gearbox? will it fit and work properly with everything? also, will the differences in gear ratios compared to an F-body 6pack make a profound difference that cannot be fixed with a set of 4.11's or 3.73's. any comments are welcome

 

The viper tranny has a different imput shaft and I am not sure it is compatible with the Fbodies. Other than that the gear ratios in the vipers make it seem just like the Fbodies since they have a 3.08 rear factory.
I think you would be better off getting a Fbody tranny and swapping in the viper shift forks.

 

thanks......i was curious because one of my buddies has a viper and happens to have a spare tranny for some reason........would be nice if it did work but maybe more trouble than it's worth.

 

I have heard that the '93 T56 M29 tranny is Viper spec. I know about the higher gearing in them but does it have the Viper shift fork?

 

Your belhousing on a Viper is different, and as someone else pointed out the input shaft is bigger. However, you can make that work, you just have to have your driveshaft end re-done. I only know this because I was looking into upgrades for my T-56 and spoke with someone at one of the Viper Speed Shops who also does upgrades for our cars. If this person is going to give you the tranny, then by all means take it and get a new bellhousing put on. However, if you are going to have to pay a decent price for it, it's better to simply order a T-56 from a junkyard for your year car. If I read your sig correctly, it doesn't sound like you need to upgrade the shift forks or input shaft or anything. If you are into the 11's or quicker in the quarter (or you will be speed shifting), then you can consider getting things like carbon pads and metal shift forks. Otherwise, I think you are adding a lot of cost to an already costly changeover. Just don't forget to get things like the clutch pedal and slave cylinder when you switch .

Good luck.

-Erenst

 

thanks for the input.....i can get the tranny cheap but i didn't want to incur big costs to make it work......if i can get it done reasonable then i will consider that option......i still need to get all the pieces to the coversion but before i told him i wanted the tranny, i thought i'd ask.........just out of curiosity, what kinda scratch am i looking at to convert A4 to M6.......i can get the tranny for about 1,000.

 

huh?

The following T56 transmissions ALL have the same gear ratios:

• All Vipers (w/3.07:1 IRS)
• 1997-2003 Corvette (w/3.42:1 transaxle, IRS)
• 1994-2002 F-Body (w/3.42:1 solid axle)

The exception of course is the Z06 corvette, which uses a unique T56 design.


The '93 tranny is NOT viper-spec. No GM T56, to my knowledge, has the Viper's cast steel shift fork (although I'd bet the Z06 has a similar steel unit in it's case)... although it's a cheap upgrade for only ~$60.

Do a search for T56, you'll find a recent thread regarding upgrades available.

 

my mistake....i thought i heard somewhere that the viper trans had different gear ratios than fbody trans. thanks for the input.

 

If you ARE looking to swap gear ratios, there are a few options. The two 1993 F-body versions have different gearing, as do the Cobra-R Mustang, and newer 2003 Cobra.

I've created a excel spreadsheet that documents the T56 gearing ratios for various applications/cars. If you want a copy, send me an email.

 

From my reserch I found that the M29 ('93 M6 w/ 3.23s) is close to the same gearing as the vipers. While the M28 ('93 M6 w/2.73s) has too deep a first gear to be worth anything.(3.?) The ZO6 T56 is the M12 close gear ratio'd within, to mimic the old M21 "rock crusher" built by mucie. The '98 LS1 M6, MN6 has different gearing than even the '99+ LS1 trannies.
But the point I am trying to make is that, I have only heard that the '93 M29s were similar to the viper spec.(yes with the 3.08 rear) Which makes more sense to me than the newer LT1 MN6s being the viper spec. Take it FWIW but thats what the reserch I have done says.


PS the ZO6s have aluminum shift forks.
The local chevy dealer has had to get 4th gear viper steel shift forks for 3 local ZO6 owners.

 

i've sent you an email twice but i don't think it got delivered......if you still didn't get it just email me the file at ettorc@hotmail.com.

thanks

 

Just sent you mail.

 

Research from where? Nowhere have I ever heard or seen anything to imply that the 94 to 02 F-bodies have any different gearing. It just doesn't make any sense to me.

Where did you find this info? If it's true, there may be more options available to use T56 owners (although I think you may be confusing the 93 vs 94+ trannies)... and all my research is wrong.

Quote:

PS the ZO6s have aluminum shift forks.
The local chevy dealer has had to get 4th gear viper steel shift forks for 3 local ZO6 owners.

wow, I guess they're pretty serious about weight savings for the Z06. Personally I'd go with the Viper one too considering. Do you work at the dealership or know the owners? That musta been some crazy ride when the 3-4 sift fork went out!

 

They don't, to the best of my knowledge.

1993 "STD" F-body T56
1st - 3.36:1
2nd - 2.07:1
3rd - 1.35:1
4th - 1.00:1
5th - 0.80:1
6th - 0.62:1

1993 "G92" F-body T56
1st - 2.97:1
2nd - 2.07:1
3rd - 1.43:1
4th - 1.00:1
5th - 0.80:1
6th - 0.62:1

1994-2002 F-body T56
1st - 2.66:1
2nd - 1.78:1
3rd - 1.30:1
4th - 1.00:1
5th - 0.74:1
6th - 0.50:1

The '97-up Y-body "MN6" T56 has the same ratios as '94-'02 F-body.

2001-2003 Z06 "M12" T56
1st - 2.97:1
2nd - 2.07:1
3rd - 1.43:1
4th - 1.00:1
5th - 0.84:1
6th - 0.56:1

Haven't had any problem with mine so far... can't say the same for the stock clutch, though.

 

ok.....so now that we know the gear rato is not an issue......all i need to make this work is the tranny itself, a different bellhousing, and a different driveshaft yoke to fit the tranny tail shaft......i can handle that. thanks for the info guys