Looking for advice for a 4L80E trans to go behind a 550 hp 496. Right now I have a couple of options. I have a close friend in the late model salvage business that has 2 trannys from 2wd's one has 250,000 miles and is out of a 2000 van and would need rebuilt,would cost me nothing for the core. The other is from a 2007 silverado classic with only 1,000 miles on the truck when it was totaled (basically a brand new GM trans) that I could get for $850.00. I work in the parts department of a GM dealership, so would have access to any special tools needed if I were to try to rebuild myself, but for some reason I am thinking that the $850 is attractive. If I install a transgo HD-2 reprogram kit on the low mileage trans can I do only the valve body mods or is it necessary to teardown the trans to do those internal mods also. Which one appears to be the better option? I am not scared to try to rebuild myself, but I dont want to tear it down twice either.

Bump.

I would go for the $850 option honestly.

The parts to rebuild a 4L80E properly are over $500. You will spend more than $350 in tools, time, and frustration trying to do a rebuild as a first timer.

I sell transmissions, kits, and parts and I think you would be hard pressed to beat a '07 4L80E for $850.

If you do decide to rebuild one, I can help you with the upgrades I would suggest.

On the '07 model, install a Transgo HD-2 kit and go. Don't worry about the internal mods.

Thanks Jake! That is what I was thinking but was after another opinion. Can you suggest/sell me a conveter if I give you a call? The car is not driven alot, so I believe it will hold up for a long time, and even better if I don't need to do the internal mods.