JD 750

Jjmw · May 29, 2015

Hey, I have a 1985 John Deere 750 that I have to hold the diff. lock lever up to get it to engage. If I let go it slips out. Ant ideas?

jd110 · May 29, 2015

The diff lock is designed to disengage by itself. If traction is unequal, it should hold itself in, but as soon as traction equalizes, spring pressure will disengage Sounds normal to me.

California · May 30, 2015

Jjmw said:
Hey, I have a 1985 John Deere 750 that I have to hold the diff. lock lever up to get it to engage. If I let go it slips out. Ant ideas?

You really mean you have to pull up on the lever, pressing it down does nothing?

Take a look at this old thread describing my repair to the same type of difflock mechanism. (And see post #7, it shows my photo that is no longer visible in post #1). The repair was simple, just weld some metal back into a worn groove and grind/polish it smooth.

The thread discusses a Yanmar of the same era, made by the folks who built the Deere 750.

Jjmw · May 30, 2015

California said:
You really mean you have to pull up on the lever, pressing it down does nothing?

Take a look at this old thread describing my repair to the same type of difflock mechanism. (And see post #7, it shows my photo that is no longer visible in post #1). The repair was simple, just weld some metal back into a worn groove and grind/polish it smooth.

The thread discusses a Yanmar of the same era, made by the folks who built the Deere 750.

It works when I press down and when I lift up. If I don't hold it in either position the back tires won't spin.

prs · Jun 2, 2015

You may have a broken spur gear shaft in one of the final drives.

prs

Jjmw · Jun 2, 2015

I've pulled both rear axles, no damage to either one.

Barry 1 · Jun 2, 2015

Are you trying to say that it won't move at all,unless you lock the diff.???

Jjmw · Jun 2, 2015

Lock the diff. or put it in FWD.

Barry 1 · Jun 3, 2015

Then you probably broke one of the pinion shafts. One on each side. The little shaft that goes from the brake drum to the diff.
Wengers of Meyerstown has used ones. CH15033(LH) $175 CH15034(RH) $150 They call it Bull Pinion shaft.