Topic: Turbo Transfer Case Question

[MidgetMike]

On the Marlin site under dual transfer case adapters http://www.marlincrawler.com/dualcase.html it says that you guy's recomend a 23 spline T-case in the rear t- case when running a turbo v6 or v8 so does this mean that a 23 spline t-case will bolt up to a 21 spline crawl box?

    Installing a dual transfer case into a 4-cyl equipped truck requires moving your existing t/case back approximately 6.5 inches. The additional crawl box is installed between the transmission and t/case. All 4-cyl gear driven t/cases are 21-spline except for the 1986-87 turbo, which is 23-spline. 2.28:1, 4.00:1, or 4.70:1 gears can be used in any combination in the two t/cases. The most common choice is one set of 2.28:1 gears and one set of 4.70:1 gears, known as a Dual Ultimate Crawler. When building a transfer case for 4-cyl applications, the stock 21-spline input gear can be used. When building turbo, V6 & V8 applications, we highly recommend using a 23-spline input in the rear t/case. Otherwise, failure of a factory 21-spline input gear is certain. Floorboard and drive shaft modifications are required. The factory crossmember remains in its original position.

 

[Benny]

I am pretty sure you have to get a 23 spline daul case adapter. Your front case could still be 21 spline.

I had a turbo motor and triple t-cases. I broke 2 output shafts. I never broke an input shaft. The output shafts are the same in both t-cases. The whole t-case is exactly the same except for the input shaft 

[cgbemis]

You just need a 23 spline coupler for the adapter. I seem to remember chris mentioning that they run around $60. If you decide to go that route, PM me, and I will take your old 21 spline coupler off your hands.

[Marketing]

I did say the couplers were $60 but I was incorrect. The V6 adapter plate couplers are $60. The correct price for the dual case couplers is $165.

For V6 or V8 apps we recommend 23 spline in both the front AND rear case. For 4cyl non turbo tranny applications, we recommend and build 21 up front, 23 spline in the rear.

If your starting from square one on a dual case 4cyl build, it costs exactly the same to build 21/21 as it does to build 21/23. Both the 21 and 23 dual case kits are the same price. The 21 and 23 gears sets are also the same price.

[MidgetMike [OP]]

What if I already have a 4.7 gear set in a forward shift t-case can I run a turbo t-case in the rear without  having to worry about the eccessive torque loads , so I can buy a 23 spline t-case adapter and a turbo t-case  and not spend any more money on the adapter but  probably a little more for a turbo t-case and not have to tear 2 transfer cases all the way down 

[cgbemis]

Do you not have the dual adapter?

[MidgetMike [OP]]

not yet I have a forward shift 4.7 case right now and am adding another case in Jan or Feb so I'm trying to find out which tcase apter will be most cost and labor effective