Transfer Case Support Mount Design

Dawnpatrol

Jesse Higgins
Joined
Apr 25, 2016
Location
Raleigh
I'm working on my Dana 20 doubler setup, with and atlas style upgraded rear output, and I need to build a rear output support for the transfer case. The common style I have seen is a simple crossmember that mimics the transmission crossmember. This would end up being two separate cross member supports that are inline with each other. Then I got to thinking about a design that utilizes the single original trans crossmember and has a single mount that cradles the transfer case and transmission together (a single mounting plate). The attached picture that shows a "rough" sketch of what I am trying to describe. The transmission would bolt to the mounting plate and the mounting plate would haven an integral atlas support ring. I am mounting the transfercase/doubler to an AX15 that has the crossmember positioned slightly behind the transmission (YJ style).

What are others thoughts on this style of transfer case support?
Do you think it would be strong enough with proper thickness plate and gussets, or would it overload the poly mount?
Would it have the potential to cause too much stress on the trans and transfer case due to the support design and the torque going through the components?
upload_2020-11-11_12-19-53.png
 
Dawnpatrol said:
I'm working on my Dana 20 doubler setup, with and atlas style upgraded rear output, and I need to build a rear output support for the transfer case. The common style I have seen is a simple crossmember that mimics the transmission crossmember. This would end up being two separate cross member supports that are inline with each other. Then I got to thinking about a design that utilizes the single original trans crossmember and has a single mount that cradles the transfer case and transmission together (a single mounting plate). The attached picture that shows a "rough" sketch of what I am trying to describe. The transmission would bolt to the mounting plate and the mounting plate would haven an integral atlas support ring. I am mounting the transfercase/doubler to an AX15 that has the crossmember positioned slightly behind the transmission (YJ style).

What are others thoughts on this style of transfer case support?
Do you think it would be strong enough with proper thickness plate and gussets, or would it overload the poly mount?
Would it have the potential to cause too much stress on the trans and transfer case due to the support design and the torque going through the components?
View attachment 330572
Click to expand...
If I'm understanding correctly, I'd just do the same thing at the front of the t-case instead. Should be a 6 bolt pattern. Throw a piece of 1/8" plate with 6 holes between the trans and t-case, weld it to a plate and then your mount, RTV it up, bolt it together, and let it rip.
 
jeepinmatt said:
If I'm understanding correctly, I'd just do the same thing at the front of the t-case instead. Should be a 6 bolt pattern. Throw a piece of 1/8" plate with 6 holes between the trans and t-case, weld it to a plate and then your mount, RTV it up, bolt it together, and let it rip.
Click to expand...
I would recommend against that. The AX-15 has a soft seal as I was told it was called. The input from the transfer case engages the output seal to the AX-15. When you space them out the fluid from the AX-15 will leak out on steep climbs. My spacer for the 203 didn't allow the AW-4 to seal. Every time I climbed I lost ATF fluid. I went back and looked and looks like my original spacer was 1/4" thick. I had it machined down to 3/16th to stop the leak. So a 1/8 spacer should be ok.
 
ghost said:
I would recommend against that. The AX-15 has a soft seal as I was told it was called. The input from the transfer case engages the output seal to the AX-15. When you space them out the fluid from the AX-15 will leak out on steep climbs. My spacer for the 203 didn't allow the AW-4 to seal. Every time I climbed I lost ATF fluid. I went back and looked and looks like my original spacer was 1/4" thick. I had it machined down to 3/16th to stop the leak. So a 1/8 spacer should be ok.
Click to expand...

You can also double up the seals on the output of the ax-15, and/or RTV seal the spacer and all, and RTV the weep hole.
 
jeepinmatt said:
If I'm understanding correctly, I'd just do the same thing at the front of the t-case instead. Should be a 6 bolt pattern. Throw a piece of 1/8" plate with 6 holes between the trans and t-case, weld it to a plate and then your mount, RTV it up, bolt it together, and let it rip.
Click to expand...
Since the doubler is a lot more heavier than the NP231, I was looking at this as a solution to take stress off of the rear AX-15 flange. I think your way would do that somewhat, but I am also concerned with the seal on the transfer case input. It uses the short NP321 input and I would rather not change that out at this point.
 
Dawnpatrol said:
Since the doubler is a lot more heavier than the NP231, I was looking at this as a solution to take stress off of the rear AX-15 flange. I think your way would do that somewhat, but I am also concerned with the seal on the transfer case input. It uses the short NP321 input and I would rather not change that out at this point.
Click to expand...
Changing out the input seems a heck of a lot easier than fabbing up a t-case mount. @scrubber3 and I unexpectedly did one on an NP231 a few weeks ago. Took about an hour if I remember right, and that was doing it twice, because I forgot a snap ring ((that was on the front outside and didn't even require us to re-disassemble :lol:).
 
Id use 3/16 or 1/4 and gusset the vertical part to the horizontal. Also I would add 1x1 square tube or bend a flange down to the bottom of the horizontal part from the mount to the end to add stiffness.
 
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