I have a 2000 F250 SD 4x4 6 speed manual 7.3L. Runs great. Clutch does not seem to be slipping. Shifts fine in all gears. EXCEPT 98% of the time I can not shift down into 1st or up into first (from Low) without grinding. Sometimes, but rarely, it shifts without grinding. If am at a stop, I cant go into 1st without pushing in the clutch and waiting about 8-10 seconds. If I start off in Low and then go to 1st, it is almost guaranteed to grind. Sometimes it even grinds going from 1st to 2nd, but that may just be me. I just got this used truck, and at first thought I was doing something wrong, but now I think I have a problem. I would appreciate your help in diagnosing this so that I dont go into the service department totally ignorant. I am afraid that if I dont do something soon I may damage the tranny. Thanks in advance

The way it sounds you may have a problem with the synchro for first gear, it may just be dirty but more then likely worn out. A synchro is a brass sleeve or thrust washer that has grooves cut into it that cuts through the oil and rubs up against the driving gear and the driven gear. In your case for first gear and tries to get both gears spinning at the same speed so they can be locked together.
That a very simplified explanation of what it does but likes its name it synchronizes two gears so they can mech. together without grinding.
You could try and change the transmission oil in the hopes that it’s just dirt and see if the problem improves, if not you may need to have the transmission taken apart and have things freshened up.
Here’s a picture of a synchro I’m not sure what it’s out of but they all kind of look the same. See the grooves on the inside that’s what maybe worn or on yours.
Dan.


Canadian "EH"

WOW Dan, thanks for the explanation and the picture!!

I will definitiely try the oil change before I let anyone tear into the tranny.

Someone suggested the master / slave cylinders may be at fault, what is your thought on that?

One other thing, I am new to this area and dont have a referral on a service shop that I can trust.
How would you go about selecting one, and what price should I expect (ballpark) if it does need a rebuild?

This forum rocks!!

It’s not likely anything to do with the clutch as it’s common to all gears not just first. As for a referral, well if you were here in London Ontario I would be able to help with that and the pricing. So I think I would be asking co-workers, friends and family as to whom they would suggest. You could try doing a Google in the local section for your area and see what pops up.
Dan.

Canadian "EH"

thanks again Dan, and happy holidays to you and yours,

George