mn_vette

Now that my older two kids have cash stashed away for college I'm looking to get another vette, probably this spring. I've got my sights set on a C6. Knowing my history with cars I have a feeling that I will be supercharging it in the future. I learned the hard way on my last corvette that certain transmissions don't like to hold power. After several rebuild and a lot of down time I just swapped over to a 6-speed manual. I'm looking to avoid that in my next car. I've been doing a bunch of searching and reading and searching and reading and it seems that the A4 and A6's tend to go out around 500-600 hp. The M6's seem to also explode at be about the same. Is there any general consensus about which one of the three holds up better? I would really like to avoid having to do transmission work with this car if I can avoid it. This car will be a daily driver with a few trips to the drag strip a year. Any thoughts would be appreciated. Thanks.

Detoxx03

Unreal

Factory 6l80s can live a long happy life at 700-800rwhp if tuned correctly. What is your power goal? Axles and rear end are typically an issue before the tranny.

ZincGT

i broke my mainshaft in my t56, but other then that I know many other people with manual cars that have never had an issue and they drag race regularly.

irok

RPM 4L65E level VI at 650rwhp.no issues

mn_vette

I'm really trying to figure out which of the stock transmissions will be the most reliable. I really don't want to mess with the transmission if I can avoid it by picking the correct one to start with when I purchase the car. My horsepower goal wouldn't be over 600rwhp.

So from the comments so far the TR6060 would be ok and the 6L80 would be ok if the controller is reflashed.

irok

Friend is on his 5th 6L80 that is built and tuned and right now it is slipping.car is about 525rwhp with a 150 shot

Unreal

Depends on which 6060, as base models had weaker input shafts. Z06 t56 held 1200+ rwhp for years, no issues. All depends on application and power level though.

mn_vette

Thanks for the replies guys. I think I'm going to concentrate my search on manual transmissions only. A little more of a pain daily driving in traffic, but should hold up better in stock form without any tweaks of modifications.

Unreal

Unless it is a z06/zr1 tranny, I would say the 6l80 is more robust for what you want. Any manual will have to have tranny dropped and a solid $1500+ clutch/etc put in anyways, where a solidly tuned 6l80 will make 600-650rwhp all day long with no issues.

Ant-Man

If you can get a z06/zr1 6060/diff go for it, I couldn't find a zr1 setup at the time so swapped my base t56/diff for a 6060/diff out of a z06.

mn_vette

I'm pretty sure the z06 and zr1 are going to be out of my price range.

Unreal, what else would I have to do to get the 6L80 to live behind a supercharged motor? A tune and an external tranny cooler? Is that it? Some of the other comments make me think with that it may not live.

realcanuk

A cooler, overfill it by one quart, and a good tune and it will live for a long time.

Unreal

Realcanuk makes 1000+ on a 6l80. Do as he says

Ant-Man

I got the entire rear cradle and rear quarters off a z06 shipped for 3400, average is around 3k for the trans/diff

2007-Vette

just curious if a person wanted could they relocate that to the back of the car without any ill repercussions?

realcanuk

Haven't heard good results from that.

c6_a6_novi

Hi - what trans cooler do you recommend?
How do you overfill by a quart?
Any special fluid you recommend?

I have '09 Z51 w/ ECS stg1 SC w/ 540rwhp and trans temp very easy to get >230F.
I upgraded radiator to DeWitts which is keeping coolant <190F but didn't seem to do anything for trans temp.
Why didn't these come with separate coolers from the factory???

Thanks

Unreal

Because factory doesn't design the car for 250+rwhp over stock.

c6_a6_novi

Understand, but I've had some pretty pedestrian, much lower-performance vehicles that came with trans and oil coolers (ok, truck and SUVs), it just surprises me that the Z51 pkg didn't include more coolers given the pkg is supposed to be a little more track/performance oriented. BTW: I'm seeing these temps with normal suburban street driving. I thought the issue might be the intercooler keep the radiator hot, but the DeWitts seems to be keeping the coolant temp well under control. I think keeping temps down increases longevity, but them again, I want electric pre-oilers to pressurize the oil system to reduce starting wear.