K10 5.3 w/6l80....transfercase needed

[Camar068]

I've got an 86 k10 currently holding a 350/700r4/np208/3.08.

I've got a 2006 5.3 w/4l60 in the garage I'm prepping for it. I really need to change the axles to 3.73 or 4.10/11 (thx HR) to take the stress off the trans. A few questions:

1. What transfer case will match up to a 6L80E? 241?
2. Do you think I'll need to change the gearing using a 6l80e? I ask because it may be the cheaper/better option. LOL it may never reach the overdrives in doing so though with 3.08's.
3. Not changing the axle ratio's, would it be better to go with the 6l90e?
4. Can I use an NP241 out of a jeep with this? I think they are different, haven't had to time to read up on them.

If it's cheaper to stick with the 4l60e I've got and pay someone to change the gearing that's fine. Just an option that's been rolling around in the brain.

Thanks Guys n Gals
'Maro

 

[Camar068]

Advance adapters has a nice search function. You can put in either the transfer case OR the trans so see what's available.

They don't have anything for the 241. I was hoping they did so I could kill 2 birds with one stone. I need to get a vss signal to the ECM when I do the swap. I'll keep digging and post what I find.

http://www.advanceadapters.com/categories/adapter-kits/191/

 

[Camar068]

NP205
1986 and Later GM NP205: 6 Bolt circular bolt pattern:
At this point GM updated the unit to use the same 6 bolt circular bolt pattern used on the NP208, and all subsequent GM full size 4x4 truck applications. All of them are the 32 spline female input, although those we have seen are the long (about 3.5" stickout) 32 spl input.

With that being said, it appears that the below adapter will work for an NP205 long input gear correct?

If so, what vehicles came with these?

Is there such a thing as a NP208 long input shaft?

Stop me if I'm way out of the ball park. I'm learnin' and can't find an answer. I really want to do this if it's feasible.

Original post:

http://www.gmsquarebody.com/forum/showthread.php?t=3477

Adapter link:

http://www.advanceadapters.com/products/50-9552b--gm-6l80e-automatic-to-the-gm-np205-circular-6-transfer-case/

 

[throttle out]

As far as a 6L80E is concerned, unless your shooting for 550 plus HP stick with your 4L60E. To make your current gearing the deciding factor in your transmission choice is not the way to do it in my opinion as you will likely want to ditch the 3:08's for 3:73 or 4:10's no matter the trans used. I'm also a firm believer that with enough ingenuity and funds anything can be made to work, but I have yet to see the newer 6 speed auto's in a 4x4 configuration (not saying it hasn't been done). Also not 100% where the cutoff is (your 2006 ECU may be capable), but some ECU's won't control the newer 6 speed trannys, so do your homework as you may need to source a different ECU. A 241c passenger drop t-case out of an 88-91 burby or k5 is a direct bolt on to the 4L60E and it has the VSS already integrated, a 208 can be modified for VSS as well. As far as the GM New Process cases are concerned, there are no long or short shaft versions that I'm aware of.
My 87 V10 short bed 5.3 is still running the 700R4/NP208 combo. I ran the truck pretty hard soon after I did the swap to try to shake some gremlins loose and the old trans never complained. I have (I believe) 4:10 gears on 33" tires and my truck happily rolls down the highway at 80mph at around 23-2400 rpm.
Good luck man!

 

[Camar068]

Thanks, I'm working on some trading to get the 4.10's in there.

I spoke with Dusty at Advance Adapters. He verified that the NP205 (1985-91) with the long input shaft and the adapter above is all you need to bolt it up to a 6L80e.

Thanks All and Dusty!
Now lets see how long I live when I tell the wife!

[edit]

Dusty sent me another adapter that may be needed if you run into issues.

http://www.advanceadapters.com/products/50-6910--gm-np205-transfer-case-spacer/

 

[yevgenievich]

4l80e would be an easy swap if you can find 1991 3/4 suburban or crew cab square

 

[Camar068]

For future reference:

http://ls1tech.com/forums/conversions-hybrids/789313-speartech-ls2-6l80e-swap.html

http://ls1tech.com/forums/automatic-transmission/1153616-6l80e-swap-questions.html

 

[throttle out]

Thanks, I'm working on some trading to get the 4.10's in there.

I spoke with Dusty at Advance Adapters. He verified that the NP205 (1985-91) with the long input shaft and the adapter above is all you need to bolt it up to a 6L80e.

Thanks All and Dusty!
Now lets see how long I live when I tell the wife!

[edit]

Dusty sent me another adapter that may be needed if you run into issues.

http://www.advanceadapters.com/products/50-6910--gm-np205-transfer-case-spacer/

Nice!!
Should be a fun truck!!

 

[Camar068]

Yeh I know. Have a source for good 6L80's for $1,000. Now comes the hard part.....finding the NP205 with long input gear....in my price range.

Well another hard part, finding a programmer within range to program the trans. No idea what that costs either.

Forgot to mention, no VSS conversion needed with the 6L80, it's already talking to the ECU. Got that from Dusty as well.

 

[Camar068]

Seeing as how finding the NP205 I need isnt going to be easy, I came across a post where I guy matched a 6l80 up to an NP241 in a 92 blazer.

Anyone know if the bolt pattern from a passenger drop np241 matches an np241 driver drop? I'm also waiting on some more info regarding the programming and the input shaft. He said he had to change his.

 

[Camar068]

Future reference. Transmission info/install pdf found at Advanced Adapters. I saved the file just in case. Lots of other info as well.

http://www.advanceadapters.com/pdf/gm_ebook.pdf

 

[Camar068]

future reference, can use an NP208 from a TH400.

http://www.gmsquarebody.com/forum/showthread.php?t=18498

 

[highdesertrange]

the NP 205 with a long shaft came in Part time 4x4's with T-350 trans and 4spd trans. the 205 short shaft came behind the T-400 trans. they are not interchangeable without an adaptor. highdesertranger

 

[HotRodPC]

Seeing as how finding the NP205 I need isnt going to be easy, I came across a post where I guy matched a 6l80 up to an NP241 in a 92 blazer.

Anyone know if the bolt pattern from a passenger drop np241 matches an np241 driver drop? I'm also waiting on some more info regarding the programming and the input shaft. He said he had to change his.

The NP241 and NP241C whether driver side drop or passenger side drop are the same bolt pattern. This means the same adapter will work for either one. To the best of my knowledge all the round pattern Tcases, NP208, Round NP205, NP241 etc, all have the same bolt pattern and even into the newer Electronic Shift Transfer cases with round pattern. Keep in mind though, just because the bolt pattern is the same doesn't mean the same adapter works with all of them. There is length differences, height differences and such.