I need straight-forward advice,
I've got a 99 Sierra with a forged 408, 232/246 112, 60lb injectors, Patriot Stage III heads, Pacesetter headers....and a 4l60 that keeps burning up. 5 times, to be exact. My tranny guy keps telling me he can fix it but...refer to afore-mentioned comment. My trans-temp gauge shows as high as 260, that'll cook any trans pretty quick. Feel like I've been hung out to dry as my transmission specialist has pretty much said he doesn't know how to fix it, except to solve the over-heating issue. Duh! So much for the money I paid him. He puts a 2-year warranty on his stuff but there's no sense in returning to his shop if it's gonna keep burning up. I do have a trans cooler on my truck but, since they also by-passed the factory radiator, it's obvious that the lone cooler isn't enough. Anyway, a few people have referred me to FLT. I actually spoke to Chuck a few weeks ago, seems like a guy that knows what he's talking about, easy to talk to, also. My solution, the Level 4 4l80e with an appropriate converter. Expensive, but I want to avoid this kind of pain-in-the-***, again. Anybody running a 4l80e from FLT? Just want your opinions about it. Also, What kind of expense am I looking at with a new cross-member and driveshaft? Lastly, will I need a new tune on the motor when the new tranny goes in? Thanks for your input.
Sincerely,
Pissed-off-in-Texas

 

4L80E is the way to go i blew my 4l60e so0 many times i got sick of it.
I'm happy with the 80E works great
Hope this link helps
If you have any more questions just pm me
https://www.performancetrucks.net/fo...ight=dmc_racer

 

I've heard nothing but good stuff about FLT.
How much power is your truck putting down and can't you route your cooler through the radiator too?

 

I run a FLT level 5 4L65e and although i make more hp than is recommended for this trans the FLT is holding up well. A 4L80e is going to be fairly bullet proof. Chuck stands behind his work, you wont be disapointed.

 

First part to buy is the biggest trans cooler you can fit. Second get a FLT 80e trans. Im buying the 4l65e lvl5. These trans are proven to hold the power. I tried the local shop thing too and i was in the same boat. I just have to get the money for the new trans, till then i just baby it. Also there is a built 4l80 and converter in the classifieds. I think it lord aries that selling it. Worth a look.

 

how much power are you putting down?
How big is the tranny cooler rated for?
What are your shift points?

the 4L80e swap is just as expensive, get some money back from your builder.
You'll need a different tune,
trans harness or a coustom one from spear tech,
trans cross member,
cross over pipe from the exhaust - might need to be modified, if you have the Pacesetter.
and drive shaft.