Transfer case mounts

[G.M.H]

I am working on a jeepster project using a 4.3/700R4/231C. I want to bolt a X-member solid to the t/c adapter and tailhousing, and put poly bushings outboard just inside the framerails. I am concerned that I might break the transmission case if there is not enough flex in the mounts.
Has anyone seen this happen due to the mounts, or am I worrying for nothing?

 

[G.M.H]

Bump. Has anyone broken a transmission case because of the mounts?

 

[dyeager535]

Only real problems I remember seeing are when mounts are mixed. IE, if you are going to use one type of mount for the trans (rubber, poly, solid) you need to do the same for the engine.

GM did at one point mount their *car* diesel trans crossmembers as you have done, although I believe the tailhousing was still on a rubber mount as well. My guess would be that was be to try and minimize the amount of vibration transmitted to the body though, and not for strength.

I know from talking to an engine builder, if you solid mount everything, with enough power you start to distort the cylinder walls in the motor, but you've got poly, so no worries there I'm sure.

Cases tend to break from being unsupported as far as I can tell, not usually from the power. GM ran bars between the trans and engine in some apps because of this.

 

[rcamacho]

Since the bushings are now several inches from the center line of the drive train they will act less flexible due to the leaver arm effect. Therefore it would be a good idea to have some softer durometer material and a solid brace from the xfer case to bellhousing.

 

[G.M.H]

I have the original rods which ran from the stock motor mounts to the trans, so I guess I will fab up a new set just to be safe. Thanks.