After installing new clutches bearings etc in our 4G D4 we are having an issue. We are trying to set gear lash but every time we check it and turn the pinion it changes drastically anywhere between .006 and .0024. Is this normal or do we have something wrong? The machine is in 1939 so I'm sure it has substantial wear. Honestly we've spent several hours to several days trying to figure this one out. According to the book what we're doing is correct but we can't seem to get consistent results.  It says to check it in four different places which we do but the spread is drastic. Any help would be greatly appreciated thank you!

Pinion shaft may be bent. Check the runout on the bevel gear and see if it is off, maybe cross shaft is bent.

Is that 2.4 thou or 24 thou? If the measurements are varying wildly every 5-10 teeth, then your pinion shaft is bad. If it's varying by a quarter or half turn of the bevel shaft, than either the shaft is bad or it's not seating right. How tight are the bearing caps?

From the sounds of it I'm starting to think the pinion shaft is bent. Even when everything free Wheels (loose adjustment) it has a spot where it gets very tight and it's hard to turn. I think the next course of action would be like was mentioned above to check the run out on the ring gear. The pinion shaft bearing is the only bearing that I didn't bother replacing but it didn't have any play. I think it said the Lash is supposed to be between 6 and 10. Our gauge is showing and reading 6 to 24. And no matter what adjustments we make it's never consistent all the way around the pinion. Thanks for the replys fellas!

Worst case replace the pinion bearing, might have a worn spot in it. If you get the pinion out put in a lathe and check the runout in the center.

I ordered a nos bearing and will start there. Good idea to check the pinion on a lathe! Going to check the bevil gear too, something is just not right.

Anything new to report?

We just figured it out today! When everything was installed we tightened up the brakes drums. The clutches on one side put everything on a bind. I can't express what a relief it was when we figured it out! We were able to get everything set, just a smidge on the loose side. Now we move forward with the project! What a relief!

Thank you call for the ideas and assistance!

That would do it too, good to hear it's solved.