Tranny Help and Ideas

[BerksBlue]

Hi Folks,  Last post was 4/2014.  I finally went with trying to switch out my 4 sp (1975 620) 4x4 ATVNW Conversion or aother company (LOW?).   I had a tranny from 1980 5 SP Man.  Same housing and lengths...

 

When I got the new one mounted, I realized after hours of futile work, the new tranny wont slip into the converstion bearings/tail stock holder that adapts to the DANA T-case.  I put on a calipers after a while and realized the tail stock on the 4 sp was macnined down .022 smaller than the standard tranny of the day. 

 

I know Boxcar, possibly RedEye have worked with these conversions.  I wonder if either of you have seen anything like that before?  I dont have pics here to drop on.  I do wonder the following:

 

Is it possible to switch tail stocks between the 5/4sp and then use the 4 sp housing with all the gears and parts of the 5SP and put back in the tranny that had the turned down tail?  I don't know how to do that, or how much work it may entail.  Thoughts / ideas appreciated.  

 

 

[datzenmike]

I don't understand what was machined down 0.022"? smaller. That's thinner than a worn dime.

 

4 and 5 speed tailstocks do not swap. There is no room for the 5th gear on a 4 speed tail.

[Stoffregen Motorsports]

I imagine it was the tailshaft housing that was machined. Probably the OD of the aluminum seal surface was machined making a nice register for the t-case input. Merely speculation.

 

If this is the case, it wouldn't be rocket science to have the 5 spd tailhousing machined in such a manner. Any dude with a mill and rotary table ought to be able to help you out.

 

I've always wanted to get my hands on one of these 620 4x4's so if you decide you want to sell it, let me know.

[datzenmike]

 

 

 I put on a calipers after a while and realized the tail stock on the 4 sp was macnined down .022 smaller than the standard tranny of the day. 

 

 

Says turned down so smaller???? Wish I was a mind reader sometimes. Or had pictures.

[BerksBlue]

[BerksBlue]

 

Image of the 5 speed w tail not turned as opposed the 4 speed above that came out.

[Stoffregen Motorsports]

Still not quite clear as to how it's assembled. Is that bottom pic fully assembled or is it in some state of disassembly?

[BerksBlue]

Disassembled. That's the 5sp I was trying to mate up before I realized the tail was turned down. It has to slide into that housing that connects w / the T Case.

[Stoffregen Motorsports]

That's what I figured. So the OD of the tailshaft housing registers the input of the t-case, right? Is the coupler free floating inside? Or is the coupler sealed off at the back of the trans, like a stock Nissan slip yoke? If it is, it must be sealed inside the coupler or the trans and t-case would share oil.

 

I would like to know more about this setup. If it's simple enough, I may be interested in reproducing the kit in all or in part. It would be neat to see more of these rigs on the trail.

[datsunaholic]

That's a strange way for any Datsun 4X4 conversion- lots of extra work.  All the ones I've seen or had, there was an adapter put on the T-case for a driveline flange, then a stub shaft was put in between the trans and t-case.  What you have looks like some sort of bastardized married T-case setup.   You're going to have to have your 5-speed tailhousing machined down, or live with the 4-speed.