I have a 88 F250 4x4 with a 7.3 ZF5. I was having problems shifting into first and reverse. Reverse was so bad that I had to shut the truck off put it in reverse and then start it up and go. I bleed the clutch and it feels a lot better but it still won't go into reverse. It is grinding every time I try. But shifts good 1st through 5th. I ran out of brake fluid so I couldn't bleed it anymore. I am going to pick up some more tomorrow and try bleeding it again.

The clutch does disengage very soon about an inch from the floor. Is there anyway to adjust the linkage under the dash? I looked at the slave cylinder while someone pushed on the clutch. And it looks like the fork is not moving as much as it should. But the pedal is at the stop. Anyone got any ideas?

 

I just looked under the dash and the floor is not flexing. But I did notice that the connecting rod coming from the clutch master cylinder had old brake fluid on it. So I wiped it off and then pumped the clutch about 10 times. Looked again and it had brake fluid on it again. Could it mean my clutch master cylinder is bad?

I just got this truck a couple weeks ago. So I don't know when it was last replaced. But the master and the slave cylinders look fairly new.

 

there should be no leakage from the master, or anywhere else in the clutch system.

 

Also check the bushing where the MC rod attaches to the pedal assy and the one on the right side of the main shaft of the pedal assy.

 

I will check those out tomorrow. Hopefully it's just the master and not something more pricey in the tranny it's self.

 

It sounds like the clutch, (edit: and probably the hydraulic linkage rather than the clutch itself) not the trans. To know for sure come to a complete stop with the trans in reverse (since that's the gear you're having trouble with). Keep the brakes on so the truck doesn't move and hold the clutch pedal down as you shift into neutral and then back into reverse. If you get any grinding you know the clutch isn't completely disengaged.

This is something to get fixed soon. If it's the clutch (and I'm pretty sure it is from what you've said), the reason you have good shifting in the forward gears is that the synchros are having hernias trying to get everything lined up. They'll do it for a while, but they'll wear out if you keep making them cover for a clutch that's not disengaging.

 

I bought the truck in my garage about a month ago now. The PO (previous owner) thought reverse was gone in it because he couldn't get it in the exact same symptoms you are explaining. I checked the fluid and it was a bit low. I drained it and re-filled with 3.5 quarts of pure synthetic ATF. Goes in reverse now just fine and stays in by itself. Before it did not want to go in while the engine was running, and if I could get it to I had to hold it in gear or it would pop out. I had not tried 1st gear prior to getting the fluid changed, so I don't know if I had that or not. Works great now.

I guess the short of my long winded approach is; Check the trans fluid

Yes, it also needs, and I will do, a syncro kit for it as soon as I can. Just so many projects in my new to me ride. Having a great time learning about the truck.

Also, from reading what Nothing Special posted, I'll have to have the master, slave, and clutch assembly checked just to be safe.

 

I will change out the tranny fluid as well. I was planning on it anyways but I was going to hold off until I. Got some other stuff fixed first. I will bump that up to a top priority.

 

You will get much better shifting and less noise out of the ZF when you go to a full synthetic ATF. I put generic Walmart brand non-synth ATF in mine when I finished up my swap. I had a junkyard trans that I didn't know what shape it was in internally. Didn't want to blow $50 on expensive ATF if it was junk.

I used the cheap stuff for about a week as a "flush" and then went to Mobile 1 ATF. Much better. I think the owners manual recommends changing the fluid at 60k, so a "new to you" truck may need fresh fluid anyway.

 

I was planning on flushing the tranny anyways. I think it may be the clutch master cylinder. There seems to be some seepage on the rod inside the cab and around we're the push rod goes into the clutch master. And when I got in it today to work on it, the pedal seemed softer then last night after I bleed it. When I started the truck and tried to put it in gear I struggled to get it in 1st and 2nd, forget about reverse. So I am going to try and replace that. I don't believe it's the clutch at all.