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Advance Adpaters said:
Advance Adapters hasn't fallen 'short' on this one - a new shorty GM SM465 to Jeep Dana 18/20 transfer case adapter kit. At 7/8" length, their adapter kit is the shortest on the market, providing a combined transmission-and-adapter length of only 12-7/8".



They didn't stop there. Their adapter is manufactured from a Blanchard ground steel plate and features three transfer case clocking options. These clocking options are at 20, 33, and 40 degree intervals. The clocking options will allow a finely tuned conversion to maximize clearance between the transmission and yoke. To obtain the adapter length of 7/8" a new SM465 main shaft was designed. This new main shaft fits 6 spline drive gears only.



The new GM SM465 to Jeep Dana 18/20 adapter is part number 50-4703. For additional information, please contact Advance Adapters at 800-350-2223 or on the web at http://advanceadapters.com/.
I decided to attempt the the mainshaft replacement myself since it was going to cost over 400 bucks to have someone else do it.

imput shaft

the old 10 spline main shaft with the second gear and third and forth gears syncro on. i dont have a press, here, to get them off so im going to have to take to someone to do for us.
 

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Discussion Starter #2
the new 6 spline main shaft

assorted parts/pieces

cleaning up, and putting the PTO covers on....

this is the back of the trans before i put on the adapter plate

and with the adapter plate installed.
 

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we set the t-case on for mock up to make sure everything would bolt up together. well it reqired some cutting and notching so that it would n bolt up in the 3rd clocking position correctly.

you can see where we trimed the case a little but to fit the shifter linkages.
 

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i got the transmission completely back together with the adapter installed


imput shaft on and getting one of the rear bearings on...

adapter plate on....
outter bearing assembly and t-case drive gear installed, and retaining nut torqued down

side view
 

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heres a few more

made new gaskets for the bottom pan on the t-case. and put one of the studs on the case.

made a new gasket for the rear bearing assembly. and ill be putting the new rear seal on this afternoon.

the rest of the studs installed on the adapter plate.

i test fitted the case on the studs to make sure everything would go together.
 

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OD?

You know Big O,,,, if you were to change that D20 out in favor of a D18 it would bolt right up to your new adapter and you could mount a Warn OD to the D18 which would give you those highway gears you've been wanting. Only thing is you'll have to swap in an offset rear axle, but one out of an early CJ5 will work and will also bolt right up.

Other advantages of the D18 are the lo range is lower than a D20, and you can install the "silent intermediate shaft mod" which replaces the needle bearings on the intermediate gear shaft with Timken bearings and removes all gear whine permanently, and makes the gearbox last for a long time. There are also lower ratio gearsets 3.15:1 available if you choose.

With 4.56's and no OD you are looking at 40-45 mph tops. This will get old fast.

I just happen to know where you can get a really good used Warn OD too.

Just a thought.

BTW, your tranny redo came out looking good, well done.

Randy
 

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Hey big O, I have to ask it, I have a Jeep with a D20 in it as well, so why go through all of that to put a D20 on the back instead of a strong NP205?
 

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Discussion Starter #13 (Edited)
Hey big O, I have to ask it, I have a Jeep with a D20 in it as well, so why go through all of that to put a D20 on the back instead of a strong NP205?
i had little to no room for a decent driveshaft length, in doing the d20 i doubled my ds length from 9" to about 18-20" i also streatched the rear by 3" i think
lots more room for a drive shaft now!!!! compared to the old one... below
with np205

with DANA 20
 
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