how do you like that gear vendors overdrive unit?

 

The cooler line is made by Sonnax. There are a few places that sell it, PATC included.

The 4L85-E, to my knowledge, is only available in 3/4 ton Suburbans, Yukons, and Avalanches with the 8100 bigblock, or in vans with the 8100 or the Duramax.

I think it's on-topic enough to answer the question about the O/D unit. There have been several discussions recently about the gearing in the 4L80-E not having a wide enough spread to give a launch in first that compares to a 4L60-E's launch. Also, overdrive isn't as high as in the 4L60-E so highway cruising RPM increases. Having a Gear Vendors Overdrive, combined with 4.10:1 or 4.56:1 gears is how you get as strong of a launch and cruising RPM as low as a 4L60-E provides with the added benefit of strength and close ratio shifts of the 4L80-E. Effectively, what the auxiliary overdrive does is give you a 5-speed in the same overall spread of range as the 4L60-E.
Final drive in first with 4L60-E and 3.73:1 gears = 11.41
Final drive in first with 4L80-E and 4.56:1 gears = 11.31
Final drive in fourth with 4L60-E and 3.73 gears = 2.61
Final drive in fourth with 4L80-E and GV-OD engaged and 4.56:1 gears = 2.67

 

So, James...will that cooler line from Sonnax work to extend my stock rear cooler line?

Also, I've got 4.10s with the 3.06 1st of the 60e now.....that's a 12.5:1 effective ratio....there's really no way I can match that with the 80e unfortunately. I did contact John Kilgore about the 2.75/1.57 and 3/1.57 gearsets he sells but no reply yet.

Im also trying to find out why the converter has a date of 09-25-04 on it yet the trans plate lists it as an 05

 

The Sonnax line adapter isn't intended to help with 4L80-E swaps from 4L60-E's, it's made to make installing a 1997-up 4L80-E in place of a earlier case line up with those existing lines.
Unfortunately the 4L60-E lines are not in the right place or at the right angles to make this a perfect solution. I had to install some elbows and other assorted plumbing on mine to make it work. It's less than optimal. Some day I will probably replace the entire line set with a 2500 set, that would seem ideal for a GMT800 truck as well.

 

Using the 2500 cooler lines is what KySilverado did, but they don't line up with the cooler in the front. It actually seems like more trouble to modify the 2500 lines than to just extend the rear line I already have. Speed Engineering does make a kit to extend the lines, but it's $100?? That seems brutally excessive to me.

 

Is it possible to modify the crossmember like Parish8 did for the swap? He was 4wd so I'm not sure if it would work 2wd. This way just looks so muck cleaner to me.

 

I don't think it'll clear on a 2wd done like that, but not sure

 

The trans pan is in the way on 2wd.