Interchangeable Parts

[Rick Shaw]

Good morning:
I have a Ford NAA with bad transmission gears. I have a line on a complete 8N transmission and was wondering if I could "cannibalize" the complete upper and lower gears from the 8N and place them in the casing of the NAA? Both are 4 speeds.
My mechanic is concerned about the bushing being a different size. Looking online for gears, I can purchase them separately and see they are listed for both tractors. Any information would be greatly appreciated.
Thanks, Rick

 

[HCooke]

This has been discussed on this board before and as I remember the answer was "no".

 

[JMOR]

(quoted from post at 11:59:41 06/25/19) This has been discussed on this board before and as I remember the answer was "no".

greed. Maybe other reasons too, but reverse is implemented differently on NAA, adding another gear on the lower shaft, as well as different reverse shift mechanism.

 

[Hobo,NC]

All the parts that start with 8N are the same... I know for a fact the main shaft is a tad longer on a NAA a 8N shaft will be to short...

I would thing the counter shaft would also be a tad short...

I tried NAA shafts by mistake on my 8N and for once in my life came up a tad to long and could not get the trans to mate to the rear end by about 1/4" plus....

 

[JMOR]

and the PTO connection to transmission shaft is different, too.

 

[Kirk-NJ]

Yes NAA shaft a tad longer. I just when thru this butting an NAA trans up to an 8n rear. Had to cut the coupler to fit.

<a href="https://imgur.com/kKqqk3l">

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[Kirk-NJ]

As said some of the gears will fit. The NAA had a larger reverse gear so the mating gear on the lower shaft will be different then the 8n.
Since the tranny is bad you might as well take it apart to see what you need. Unfortunately when gears get busted on the top cluster it has a
trickle down effect and the busted teeth get caught up in the gears on the lower cluster.