Edit: I have a 2007 Automatic LT. I was on a nice mountain drive yesterday with some local Cobalt owners. We went up a road that had some fallen rocks on it. I wasn't able to dodge one of them and it ended up punching a hole in my transmission pan and cracking the tranny housing, so I need to get it replaced. My insurance is assessing it tomorrow, but they said normally they would either pay for a rebuilt tranny from GM, or a new tranny minus a percentage based on how many miles are on the current car. Since my car has 31,000 miles, they said they would cover 80-85% of the cost of a new tranny from GM (all prices will be MSRP). I forgot to ask how much they would cover for labor, but I'm sure they'll have a set amount of hours they'll cover.

Anyway, since my transmission needs to be replaced and a good portion of it will be covered, I was wondering if there are any good after market transmissions out there that will fit the car and provide a moderate improvement without sacrificing street driveability? I was hoping for something designed for street but allowing some track drag use, but nothing that will make long drives or daily scooting around town difficult. Most importantly, a transmission that will take the added HP and torque I'll be putting into it by the end of this year when I have all my upgrades (intake, header, turbo, tune, fuel rail, 3" exhaust).

I did see in the build book they used a 4T65-E transmission from a Pontiac Bonneville and heavily modified it, and somebody suggested it to me on these forums, but I was wondering if it would take any special care or be a pain to install?

 

Yes, Quaife 6 speed!!

https://www.cobaltss.net/forums/drivetrain-79/quaife-6-speed-conversion-fgp-f35-5-speed-manual-transmission-50610/

 

Forgot to mention I have a 07 auto Lt

 

Anyone? I have been doing more reading and in the GM build book they used the 4T65-E and modified it, but it needed a custom adapter plate to fit since its going from a 6cyl to a 4. I'm just wondering if it would cause any problems.

Here are some specs for comparison:

Stock Cobalt (GM 4T45-E, or MN5)
Torque = 205 ftˇlbf (278 Nˇm)
Max Weight = 4500 lb
Final Drive = 3.63:1
Gear ratio'sBonneville (GM 4T65-E, or M25)
Torque = 280 ftˇlbf (380 Nˇm)
Max Weight = 6500 lb
Final Drive = 2.92:1
Gear ratio'sHas anybody done this before? Does anybody know if the install itself is labor intensive or not? I'm having a friends father's shop do it for me and I don't want to rack up a ton of labor costs. Also right now I don't have any performance mods done but I am planning on getting cai, intake manifold, fuel rail, ignition, exhaust manifold, dp, 3" exhaust, stage 3 turbo (when tuning is complete), header, rods, and pistons. So with those mods, would the tranny become useful or is it not really needed? And last, with those gear ratios, will it affect my performance now in any way (positive or negative)?

 

get your tranny redone at ipt maybe

 

Should I just get an IPT 4T45-E then since they totally rebuild them?

 

yeah a built one would be nice

 

Way too expensive and he as an Lt Auto.