Tranny Trouble

TMoon: If the Straight 5 speed is not a problem what does it matter if it has a 3 spd box behind it? Is it broken? They could be useful for parade use. Low gears that would allow you to creep along and not use the clutch. Because it has all those gears does not mean you have to use them all the time. Maybe try it out first.
Housings are numbered SAE 1-4or 5 and your engine is the largest a 1, around 23 inches, I thank?
Your 643 was made for engines like a dt466, 3208, C-series, etc. They have SAE 2 housings, around 20 inches, I thank. Also set up to shift at a higher RPM than your engine likes.
I do not thank the 643 was offered with a #1 front section, which is interchangeable, or your engine was offered with a #2 housing.
My thanking was if a refurbished 6x6 can be bought for about $15,000 delivered, you could likely buy the correct transmission and all the extras for a lot less than you can install a 643 that you own.

 

I was gonna say tell him to pull his dress up and #### his mouth.

 

But would that not have been a left leg work out for a parade? Straight stick meaning rear box in high the same as having only a 5 spd, correct?

 

Straight sticking you would have the brownie in direct, which in a 3 speed should be second.

 

You can study and ask that question all you want but if you make sure the the auxialy is in direct, input and output shafts turn 10 turns to 10 turns, then drive it. That to me is the only sure way.