Well the 4L70e blew and I didn't want to put a built one in and still have the same gear ratio so I decided to go 6 spd and it was WELL worth it! I would like to thank Skipperdaddy for tool usage! Keniff for constant guidance! And especially Truckshop for the tune and patiences!! These guys are top notch!

I purchased a 6L80e from "GoneB4U" from this site. It came with a AWD transfer case (TC) which I never planned on using. BTW he was a great seller!
So to start I didn't know how much was gunna be different from Keniff's but it's defiantly not passed the normal DIY'er!

•6L80:


•30K Tranny cooler from jegs with 6AN pushloc fittings and hose:


•Circle-D multidisk 3500 converter and billet flex plate. ( these pieces are bad ***!!)


•Now I assume y'all can remove your own tranny so once that's done start putting on your new kick *** flex plate


• from there install converter and bolt up that heavy *** 6A (sorry no pic)
•The spacer/adapter that come with 4L70e needs to stay with old tanny cause it's about 2" to long! The one that's on 6L80e is about 3 1/4" long and that's why the stock crossmember works like factory!


•Now it's time for the fun part! Need to unbolt and crack case open on TC, to do this you'll need a big torx bit and a big flathead screwdriver. Also your gunna have to pull the two rubber plugs at output shaft tail housing to get to a big snap ring. Gunna have to get it to sit in its channel to get case fully apart! Once case is apart you can remove input shaft seal with flathead ( do it gently and it can be reused!) from there you'll need to remove the snap ring behind seal. The planetary should come out, then use flathead to get the C clip in its channel in order to separate the planetary from input shaft!


•The difference in the input shafts:

•From there reinstall, then bolt TC up to tranny
•The Dshaft can be reinstalled cause output shaft on TC was never changed and length is the same due to the shorter TC mount from tranny

•I went with the tranny cooler block that converted it to 6AN


•Just mounted cooler on passenger side behind grill


•Now what you all have been waiting for....parts #'s
Wiring harness: 20821966. 330$
TC input shaft:19132978. 178$
•Now I had to repin my wiring harness also just like Keniff and I didn't take many pics of that cause it's been done. From there the truck ran and drove but ECU was telling TCU I was going 158mph so it shifted quick! I took my ECU to Geoff at EPS and he put a '08 Denali operating system in it so it would communicate with TCU. Then I got Truckshop to tune tranny to work better with converter. And the rest is as they say melted rubber and smoke...well that's what I say!!
Hammer truck easy launch in 2wd - YouTube

Hammer's truck 45-120 - YouTube

That's all folks!

 

nice write up , and a great swap for sure!
i drove my friends 08 with a 4 speed with same mods as i have when it was bolt ons only and i hated the 4 speed , it feelt like a turd

congrats , this will hold up pritty good with mods or beating

 

You're welcome buddy. Glad my truck was your whole reason for wanting the 6 spd when it hit 4th an kept pulling


You can refer to my write up then just add this if you are going 4wd.

 

What's the part number for the AN adapter?

 

Oh good Lord that's exciting. Thanks for the write up, and for being the guinea pig. Has a 4x4 been done yet anywhere else? And did you have to swap the cluster like Niff did?

 

I don't know if I was the first 4x4 or not?

No I didn't swap the cluster! Mine still says -PRND321 but won't go down to 1.(doesn't bother me at all)
Imma have to get the part # to the 6AN block when I get home...sorry

 

i didnt swap the cluster. with the research ive done, you have to bring the truck to the dealer with a 2500 vin that has the EXACT same options as your truck unless you have a fully loaded truck (i dont) to have the bcm flashed. only issue is they can be flashed once according to the GM tech. so you'll have to buy a BCM or go find a bcm from a donor truck with the same options that you have. then take it to the dealer to revin your radio. im not willing to spend 800+ trying to make the cluster and TU/TD work.

my truck does everything i want it to so im done until it breaks

 

Sorry for so long to get this posted and can't find part # but here's a snap shot of the site/part!

 

I want a 6 speed! Lol

 

Haz anyone done it in a nbs truck yet?