8-Speed Round Hood

[DBlackston 298]

I have a 704 that had a bad transmission. I also have an 8 speed that came out of a C-111.

 

The 704 has a K161 motor in it. 

 

I have new brake rods and clutch linkages from a raider that should take care of the problem of the brake drum being mounted on a different transmission shaft in the 4 vs 8 speed. 

 

I have read somewhere and now I can't find it that there is a different sized pulley I will need to run on the input shaft to be compatible.

 

Can anyone point me in that direction?

 

Heres a picture of the project tore apart in the bed of my truck. 

[71_Bronco 1,072]

I swapped in an 8-speed into my Commando 8. I happen to find a 5060, which has the same brake configuration as the stock transmission. This also gave me 1-1/8" axles, and the 10 pin limited slip differential (not that I need it with my 8hp K181 lol).

 

For the input pulley, I kept the same 4" diameter (same as the 3 speed), but had to find a new pulley since the input shaft diameter was different on the 8-speed vs the 3 speed.

 

I think I ordered my pulley from a company called Phoenix Manufacturing. They claim to make all different OEM pulleys. I was able to get a cast iron pulley with the correct OD, correct ID, and made for 1/2" belts. All the other "stock" pulleys I found were for 1/2 AND 5/8 belts (making them wider).

 

This change will allow my ground speed to stay the same, and now gives me the low-range of the 8-speed.

 

Edit: You can use whatever outside size pulley you want. The size difference is in the shaft size on the transmission. I used 4" (same as the stock 3-speed) so the belt guard wouldnt change, the stock drive belt would fit, and it wouldnt alter my ground speed.

Edited July 18, 2020 by 71_Bronco

[DBlackston 298]

Wait a minute, your explanation has me thinking

 

I have a SR-64 cover that would allow me to run a larger pulley. 

 

What if I left the pulley on there it has now, and I use the low side of the transmission for regular speed, and have the high side be faster than stock?

 

Kind of reverses the idea, definetly cheaper and easier to do, and this tractor will be much less of a worker and more of a toy than my 854.

 

Edit: Disregard this is the exact opposite of what would happen. Using the original pulley from the c-111 trans would make it extra slow!

Edited July 18, 2020 by DBlackston

[stevasaurus 22,863]

Correct me if I am wrong.  I know that all of the Wheel Horse transmissions...3,4,6 & 8 speeds all have the same gear ratios (the 3 & 4 speeds being the same as high range in the 6 & 8 speeds).  I would think that the input pulley that is on your 8 speed transmission will give you the same ground speeds as your 3 speed transmission with the 4" pulley...with engine RPM's being equal.  Unless the engine pulley is a different size between the 704 and the C-111.

 

Are the engine pulleys the same size???  

 

If the engine pulleys are different diameters, I think there is a formula to determine what size the input pulley needs to be to give you the same ground speed.   

[953 nut 55,771]

I remember @WHX24 and @Racinbob were having a conversation about pulley size. Page 218 of this thread.