Need answers for 1981 JD 750 Dozer problem

[texascowman]

Pushes and steers fine at 3/4 throttle but not at full throttle. Filters are new. Any suggestions or knowledge much appreciated.

 

[AGGIE00]

Need a little more info on the dozer. Transmission mainly.

 

[texascowman]

hydrostatic drive (2 drive pumps, 2 drive motors)

 

[Bob Rooks]

Is the issue the same on both sides or does one side seem to have more power than the other?
How many hours on the unit?
Have the pumps or motors ever been rebuilt?
Have you checked the motor controls?

 

[texascowman]

Haven't had it all that long. Unk if anything has ever been rebuilt. I recall the left side being a little stronger when we first got it. Hour meter is broken.

 

[Bob Rooks]

Haven't had it all that long. Unk if anything has ever been rebuilt. I recall the left side being a little stronger when we first got it. Hour meter is broken.

If your issue is linear, that is the same amount of loss throughout the throttle range, it might be that the right motor is slightly off stroke and may just require control adjustment (you will need a manual for the specs). If the loss is logarithmic, that is the loss becomes greater with throttle increase, it could be time for a motor rebuild. Too bad the service meter isn't working, they are kinda important. Simple thing to check first is the pump couplings.

 

[benjahmen]

any one no what could be wrong with a 750 b long track the moter starts fine but nothing else works herd it could be a main shaft that comes out of the moter and goes in the gear box any awnsers ?

 

[Bob Rooks]

any one no what could be wrong with a 750 b long track the moter starts fine but nothing else works herd it could be a main shaft that comes out of the moter and goes in the gear box any awnsers ?

The B series should have the dual path hydrostatic drive. Any oil in it?

 

[Wolfy]

My 750B sat for a few months. It fired right up but would not move. The auto parking brake had seized up.