Installing B1550D Transmission on B7100D, any pitfalls?

[droughty]

Hey Kubota enthusiasts, I'm after some advice/expertise.

I have a 1980, B7100D 6 Speed Manual 4wd, with a transmission in need of a rebuild, I found a used unit from a dismantler, and when it arrived it appeared different. The Dismantler was adamant it is off a 7100D, but I have done some research and believe it is off a 1550D.

I haven't been able to locate another 7100D trans, so am considering installing the 1550D trans on my 7100.
Buying parts to fix the existing tranny doesn't make economic sense now.

The trans case is identical, just a few minor differences with the front and top cover with the shifter being mounted on the side on the 1550.

The 1st drive spline is larger, but i have the 1550 drive shaft on hand, and it fits like a charm into the 7100D clutch, the shaft length is identical between the 2 models

I realise the max engine RPM on the 7100 is 200rpm higher than the 1550D which should give me a better top speed.
The 1550 has more HP so in theory the trans should be stronger than the 7100.

The tyre sizes across the 2 types appear identical.

I've already done a dry/test fit and all appears well so far..

Any pitfalls anyone can think of that aren't obvious to me before I make this a permanent fix?

Cheers and looking forward to any comments.

Droughty

 

[North Idaho Wolfman]

Very interesting!
Does it mate up the the B7100 rear end housing?

 

[droughty]

Very interesting!
Does it mate up the the B7100 rear end housing?

Hey, yeah it just bolts on no issues, it all seems to line up...

 

[hodge]

You've got it, I would imagine that the seller won't take it back, or won't pay for the shipping, and it appears to bolt up. You might as well move forward, and see it if works.
You are probably in some uncharted waters, so you may not get any first hand experience input. However, you may be first hand experience input, for the next person!

 

[droughty]

You've got it, I would imagine that the seller won't take it back, or won't pay for the shipping, and it appears to bolt up. You might as well move forward, and see it if works.
You are probably in some uncharted waters, so you may not get any first hand experience input. However, you may be first hand experience input, for the next person!

Hi, i'm thinking much the same, what could possibly go wrong right?
i'll post some updates when I make progress for those interested!