4-speed to 5-speed 800 series rear end swap

[texfordfan]

I am considering switching my 4-speed to a 5-speed. Will the 5-speed from a 800 series work with a rear end from an industrial 4000?

 

[Fordfarmer]

I am considering switching my 4-speed to a 5-speed. Will the 5-speed from a 800 series work with a rear end from an industrial 4000?

If I remember right...no. it will bolt up, but there were changes with the spline count on couplers (can be worked around), and also brake shaft location.
Someone please correct me if I'm wrong.

 

[Tony Jacobs]

If I remember right...no. it will bolt up, but there were changes with the spline count on couplers (can be worked around), and also brake shaft location.
Someone please correct me if I'm wrong.

FordFarmer , You are correct but since TexFordFan didn’t list any real info like serial numbers or casting numbers who knows if it is even an 800 series since most guys call everything an 800 series wether it is or not .

 

[Sean in PA]

If I remember correctly, and that seems to be happening less as I get older, the spline count change happened during the '01 series production run, so the 4000 transmission output shaft should have the fine splines and the 800 series rear end should have the coarse splines, but as Tony Jacobs said, things might have been swapped over the years so they might both have one type. The only way to be sure is to look at them to see. If they are different, some folks here have had success with splitting two couplers, one coarse and the other fine, and welding the two halves together.

 

[texfordfan]

It is an 860.

 

[sotxbill]

It is an 860.

Can you take the whole back assembly from including the flywheel, clutch and everthing back??,, Then it should fit.. Might even include the starter also...

 

[texfordfan]

The rear end on the industrial is the heavier version of the rear end and I'd prefer to use it.

 

[Sean in PA]

As has been said, you need to take things apart to check the spline count on the transmission output shaft and the input shaft to the rear end. If they are both coarse, or both fine, then it will be a direct swap. If one is fine and the other is coarse, then you will have to do something to make it work. Either swap out the transmission output shaft to one from a transmission with the coarse splines, or swap out the rear end input shaft, or take a coarse spline coupler and a fine spline coupler and cut them in half and weld the two halves together.

 

[Tony Jacobs]

The rear end on the industrial is the heavier version of the rear end and I'd prefer to use it.

You’re worried about the heavy duty rear end assembly when you want to change to the weakest clutch and transmission combination made by Ford . That’s why 5 speeds were Never offered in Industrial tractors .