Hey guys. Long story short- stock bottom, heads/cam car LS1 based. T56 car originally, want to switch to an auto. I haven't been able to get a clear answer on which transmission I should go with an why. If you vote, drop a message saying why you chose that specific transmission for my setup.

Goal is eventually going to be a "9 second street car", LS3 based, FI or N20. I have a company truck I drive during the week. The T/A is my primary car otherwise and see's city and highway driving on the weekends. Car is full weight now, and will probably never be too much lighter considering a 6pt cage, etc will be added to offset any weight reduction.

Any questions ask. Choices are TH350, TH400, Powerglide, 4L60e, 4L80e. My car is a 1998 car, so if I went with 4L80e, I would have to swap to a 99+ PCM and what not. Still researching what needs to be done with that.

Thanks for looking,
Andy

 

well if it will be driven on the street and highway then the 4L80E is clearly your best choice if you want to keep an overdrive and still have a good gear in the rearend and still run the times that you want.

 

It will be driven on the highway until I get another vehicle (beater)

 

I think a built 4l60e can handle your goal for 9's, prolly not much more than that tho!

 

i say get the 4l80 because its stronger then the 4l60 and has an overdrive unlike the th350-400

 

4l80 all the way, people on here have been rocking the junkyard built ones including myself

 

If it's going to be a 9 sec street car you will get tired of no OD with a 400, and will get tired of breaking 60's. Just get an 80 right from the start.

 

I'm thinking a manual valve body might be the best option for me. It's basically a TH400 with overdrive, and I wouldn't have to swap PCM's/harnesses/etc.

 

Yeah I agree. The PCM harness swap will be a pain and not worth it IMO. I'd go with a 4L80E with a MVB and you'll be covered. We had great luck with our built 4L60E, but we were already set up for it with the 01 PCM. Since you have to do a conversion anyway, you may as well cover yourself with a 4L80E and manually shift it. If you are going to see freeway driving, an OD is a must.

Circle D or FLT can build you one that you'll never have to worry about.

G/L

 

I already have a builder in line

I was going to contact Circle D to see what they could do for a converter. It's between them and Coan.

 

The 4L series converters are Circle Ds specialty and I believe they offer one free restall to LS1tech members. That's a no-brainer especially since the cars final HP hasn't been confirmed yet. It seems we always want a little more stall.lol.

G/L and keep us updated on the build.