buying a used zf5

[rtyoung27300]

I'm trying to convert my 1983 f250 6.9 diesel from the T19 Borg Warner to a ZF5, well long story short, I found one that isn't installed in the truck. When I shift gears and spin the input shaft with my hand, it's very hard to turn (almost impossible by hand) in first and reverse. All the other gears seem to spin easily with minimal effort. Is this normal?!

 

[79jasper]

Probably normal.
A lot of weight to spin by hand.


Sent from my iPhone using Tapatalk

 

[cpdenton]

Are you spinning it from the input shaft or output yoke? First and reverse will be easier from the input shaft and much harder from the output yoke. Due to the gearing of those gears.

 

[jas88]

Nevermind.

 

[rtyoung27300]

I tried spinning it by both, the input shaft and output shaft (I guess that's what you call it. A where it goes into the transfer case.) Does the direction of rotation possibly make a difference? I'm just really wanting this transmission to be okay. I've been looking for one for so long.

 

[icanfixall]

The imput shaft of the trans is the part that sticks in the clutch and bolts to the engine. That end will spin the trans gears very easy in both first and reverse because of the low gearing. More turns of that shaft to one turn of the output shaft. Now when you try to turn the output shaft in first or reverse you will have a tuff time doing it. Whats happening is you have the higher gear turning the lower gear making the input shaft turn many times what the output shaft turns. Think of it this way. Look at any belt drive motor on any shop machine. The small pulley is the input shaft end and the large pulley is the output shaft end. Try turning them and see how hard or easy it is from either end. Also notice how many times the smaller pulley turns compared to the larger pulley turning one time. Same thing is going on in any trans.