Iam swapping in a TF 727 under my junk. I am trying to keep my skid as flat with the frame rails as possible. The tranny mount normally used would drop below the frame rails.

I plan on making a crossember with some poly shackle bushings. Similiar to this

http://www.pirate4x4.com/forum/attachment.php?s=&postid=817103

Do you think this wil be forgiving enough? Or will I pull the bolts out of the tranny. I am running MORE mounts for the motor, so there should not be a lot of movement.

If your talking about bolting that cross bar hard to the case adapter, I would consider it carefully. I've seen people successfully run cross members like that, but I won't. I think it's too rigid and would lead to a higher incidence of adapter or case breakage. Poly bushing don't move much anyway. Consider that along with the fact that any attempted torque at the center mount location will be amplified by the "arm" and you can see that the mounting point is effectively going to be frozen in place. If the engine is not located with at least the same rigidity, you'll have trouble. And, since the most rigid engine is usually mounted to 2 outboard poly mounts, it is unlikely that the engine will be located as consistently as your tranny mount. I'm considering designs for a newer high clearance cross member and plates for my junk after being denied an otherwise (relatively) simple obstacle last weekend just because I got hung and pivoted on that stock POS. One of my current thoughts includes running to a cross member similar to yours with an additional soft (rubber) saddle mount in the center... Still undecided, and I may well try to use the factory mounts again. I prefer factory type parts on stuff like that for ease of replacement when out of town so I generally avoid "custom" stuff for pieces like that...

I'll add to this that I am currently hooking this to a decent running 258 with Howell FI. I was firguring since this was an automatic and only an I6, that it would work?

You might try swapping the poly bushings for stock Jeep TJ upper control arm bushings. They are a press fit bushing, MORE (Mountain Offroad) uses them in some of their motor mounts (torsion rubber) and they dampen the vibrations well.

I made this with poly YJ srping bushings on the ends...bolts to the bottom of the tranny...I'll let yall know when I break it, or the tranny or other associated parts.


Pushed the t case up through the floor a little in my CJ...and I have about 1/8" from the bolt heads to my flat skid.

I am worried about the engine and xmemebr twist differerences...time will tell how it goes.

MJ

here it is mounted under the 176/d300 just welded (bolts as well) brqckets to the inner frame rails.

I think with new motor mounts I will be OK for a while with the 258...any more HP and something will go boom I'm sure.

MJ

If you run a deep pan then it will hang lower then a mount directly bolted to the 727 tail housing. I believe you could mount the tranny mount directly to the tail housing, the bottom of the tranny pan will then be at the same level as the bottom surface of the tranny mount.

I know with the 4:1 gears in my 300 I have to replace the engine mounts because the engine moves around far too much. I can't imagine the movement you'll see out of the mount due to the leverage of the mounting bracket out that far away from the tranny. I'd bet you'll tear up the engine mounts, or the tail housing if you get on it at all.

Originally posted by BadDog
... If the engine is not located with at least the same rigidity, you'll have trouble. And, since the most rigid engine is usually mounted to 2 outboard poly mounts, it is unlikely that the engine will be located as consistently as your tranny mount. ...

Ummmm dude, he gave you all the information and you missed it. MORE motor mounts look like this:
http://www.mountainoffroad.com/catalog/BombProof%20MM/JM100is-3.jpg

Essentially the engine IS located with the same rigidity.

For what it's worth, I plan the same setup (yes, I am also running MORE mounts too). I see no problems with it. I need more beef to keep my nv4500/Atlas in one place, especially since the t-case doesn't have a torque-arm.

Actually, I didn't miss it, I just didn't know what the MORE mounts were like. :D I’ve heard of them, but I just didn’t have a mental (or otherwise) image to put with the name (and was too lazy to hit google). Thanks for info, it does look like it might be ok with those mounts...

However, IMO, I would still rather have some more wiggle on the rear mount. I would just hate to see a busted tail shaft/adapter because the rear mount was trying to limit the torque. To me, the rear mounts purpose is support and horizontal location...