Trans/Transfer Case Combo Opinions Needed

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

MtBraun

Full Access Member
Joined
Sep 27, 2017
Posts
455
Reaction score
306
Location
South Dakota
First Name
Matt
Truck Year
1984
Truck Model
K10
Engine Size
632
Targeting 700hp in a 496. Pretty sure I want a 4l80e for OD and can be built to handle that power. Looks like the NP241c is a unicorn and not likely to find. What do you guys think of 205 vs. 208 for this combo? 4.11 gears with 35 or 37" tires. Some trail and rock crawling, otherwise just horsing around with the truck. Thanks!
 

Tank6x2

Supporting Member
Supporting Member
Joined
Mar 27, 2017
Posts
837
Reaction score
705
Location
Edmonton Alberta Canada
First Name
Kurt
Truck Year
79/86
Truck Model
C30
Engine Size
350, TH400.4:10 gears 2WD
I’m not sure what your unicorn looks like but this one is 400$ Canadian/ 275$USD not sure if it’s what your after though.

 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,698
Reaction score
6,693
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
And I just tossed one in the scrap pile I took to the recycling center. I guess my collection of late model 205's has diluted my mind.
 

MtBraun

Full Access Member
Joined
Sep 27, 2017
Posts
455
Reaction score
306
Location
South Dakota
First Name
Matt
Truck Year
1984
Truck Model
K10
Engine Size
632

MtBraun

Full Access Member
Joined
Sep 27, 2017
Posts
455
Reaction score
306
Location
South Dakota
First Name
Matt
Truck Year
1984
Truck Model
K10
Engine Size
632
And I just tossed one in the scrap pile I took to the recycling center. I guess my collection of late model 205's has diluted my mind.
frankly I'm not locked in to a 241. The truck had a 700R4/208, which isn't going to work for this build. Maybe I should just go with a 32 spline 205?
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,698
Reaction score
6,693
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
If you're really pushing a 700hp big block, an aftermarket unit is probably your best option. Atlas. Buy once-cry once.
 

77 K20

Full Access Member
Joined
Nov 9, 2012
Posts
3,076
Reaction score
3,051
Location
Montana
First Name
Mike
Truck Year
1977
Truck Model
K20 5" lift
Engine Size
HT383 fuel injected
I once asked Offroad design about a 205 vs a atlas and they said the atlas was designed for more light weight vehicles (jeep) and the transfer case follows that- more light weight and not really meant for abuse.

For instance the idler shaft has thrust washers on it vs a tapered bearing. Atlas is smaller, thinner, weaker.

Atlas is on the left:

full
 

MtBraun

Full Access Member
Joined
Sep 27, 2017
Posts
455
Reaction score
306
Location
South Dakota
First Name
Matt
Truck Year
1984
Truck Model
K10
Engine Size
632
If you're really pushing a 700hp big block, an aftermarket unit is probably your best option. Atlas. Buy once-cry once.
I spoke with Atlas. They were really helpful, and thought their "race" class transfer case would hold up to that torque level....but that's a whole lotta cryin up front, man! I have to believe someone out there has built a 205 to handle similar torque for a lot less than what an Atlas cost.
 

MtBraun

Full Access Member
Joined
Sep 27, 2017
Posts
455
Reaction score
306
Location
South Dakota
First Name
Matt
Truck Year
1984
Truck Model
K10
Engine Size
632
I once asked Offroad design about a 205 vs a atlas and they said the atlas was designed for more light weight vehicles (jeep) and the transfer case follows that- more light weight and not really meant for abuse.

For instance the idler shaft has thrust washers on it vs a tapered bearing. Atlas is smaller, thinner, weaker.

Atlas is on the left:

full

I've had a number of conversations with Kyle at Offroad Design. Super helpful guy, I will definitely do some future business with them. He said they can take a 27 spline 205 and convert it to the 32 spline to match up the 4l80e. Just takes some machine work to the case. I thought that was a creative way to get more options for the case. And he was also comfortable that they could build a 205 to handle the torque my build will have, for about half the cost of an Atlas.
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,191
Reaction score
5,092
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
My 1980 is originally a 350/TH400/NP205, so I already have a 32 spline input 205. I am putting in a 454/4L80e combo and keeping the 205. I already had the 205 apart and cleaned/rebuilt it. It is an absolute beast and I can't imagine you are going to break one. I just needed to swap out the 4wd output and put in a long fully-splined 2wd shaft into my 4l80 and then got an adapter plate to convert the TH400 index ring on the T-case adapter to the smaller 4l80e index ring size. When I pull the TH400, I'll measure how much the stock output shaft sticks out and then cut the 2wd output on the 4l80e to match. It was only ~$100 for the adapter and like ~$15 for the used output shaft. If you have the later model 205 with the long input and circle adapter, then don't need anything changed. The stock 4l80e 4wd output will bolt right up.
 

nvrenuf

Full Access Member
Joined
Jul 30, 2010
Posts
1,725
Reaction score
1,941
Location
Mobile, Al.
First Name
John
Truck Year
1991
Truck Model
K5
Engine Size
454
If you are going to be rock crawling you'll probably want more tcase or axle gearing. I'd suggest a Magnum/np205 combo, that's plenty strong enough.
 

MtBraun

Full Access Member
Joined
Sep 27, 2017
Posts
455
Reaction score
306
Location
South Dakota
First Name
Matt
Truck Year
1984
Truck Model
K10
Engine Size
632
If you are going to be rock crawling you'll probably want more tcase or axle gearing. I'd suggest a Magnum/np205 combo, that's plenty strong enough.

Probably not enough rock crawling to warrant that, but Kyle and I did discuss that option. I have found a core 27 spline 205 and what is supposed to be a 32 spline 205. So I'm feeling better about that, as I had done quite a bit of looking for the 205 and hadn't much luck locating one.
 

Forum statistics

Threads
42,124
Posts
909,617
Members
33,617
Latest member
dougli1
Top