replacing a super 10 with an old transmission

I have a super 10 that is about worn out. I have a 1985 Freightliner cabover that has been parked for about 20 years. It has a 9 speed 12609 transmission. I know the 12 refers to torque rating. My super 10 is a 14610, with a 14 torque rating.

My question is not about the torque rating. My question is, will it fit?

Are the bolts in the front the same?

I figure the front shaft may be smaller, but I don't know that yet.

The clutch should still be good in the old 85.

Can I swap the two transmissions, clutch and all?

I was told that it's easy and relatively cheap to turn the 9 speed into a 13 speed by adding a backbox. I'd like to do that.

Does anybody here have any experience doing something like this?

How about the shifter? The cabover shifter is different from a conventional.

 

I forgot about the overdrive. Thanks for reminding me. For most of my driving with the super 10, I can drive in 9th gear, which is straight through, no OD. So high gear in the old 9 speed would be same thing. If 13 speed gives me 12% more, I could live with that.

I don't like the super 10. It's been dependable, I have to say that, but waiting for it to shift is too much of a PITA. I'd love to be driving a 13 speed.

As far as the torque rating goes, I can easy pedal the truck. I've never been one to get down hard on a truck.

 

The 9 speed is in the cabover with the shifter on the doghouse. The super 10 is in a conventional with a tall tower.

I'd have to deal with that.

I think they're both electric speedo. I'll have to have another look at the old cabover.

The project may turn out to be more trouble than it's worth.

It's just that the super 10 is about worn out and I don't want to replace it with another super 10.

I have prices on a 13 speed or an 18 speed, both reman—$5,000 and he doesn't want the super 10 for a core. $3,000 if I'll settle for another super 10.

The other day I had the thought about the 9 speed in my cabover. I wouldn't mind the trouble and expense of upgrading it to a 13 speed, but if the speedo won't work, the shifter won't work, the clutch is too small, and the yokes are different size, then by the time you add in the labor and down time I might just as well hand the keys to my local dealer and tell him to install the 18 speed and I'll pick it up in the morning.

 

Being the 9 speed is a 12 instead of a 14 I figured maybe the front shaft would have a smaller diameter, smaller clutch splines.

I believe I'll yank that transmission out of there just for the sake of getting it into the daylight. It's been sitting there for 20 years.

 

That's good news.

With regard to the yoke, I have a torch and a welder. I think I can deal with that.

I'll check that out.

I could find out about that by raising the cab. It hasn't been raised in 20 years.