I have a 1997 F350 7.3 with the zf5 tranny. Today I went on an hour drive and it's about 90° outside. This isn't the first time that it's happened but I figured I'd ask you guys since you have a lot of knowledge

What the problem is is that after I drive it on the freeway or drive it for a long amount of time I'll get to a stoplight or parking lot and the transmission seems to grind. Especially when trying to put the truck in reverse , it seems to grind a lot. I have to put it in first or second gear before I try putting it in reverse for it not to grind.

I just changed the transmission fluid and the transfer case fluid about 5000 miles ago with the recommended Mercon fluid that's tagged on the side of the transmission. I'm not sure if this fluid is too thin or too thick or something causing it to grind but like I said it seems to happen more often when the truck is warm

Any ideas or any suggestions would be helpful thank you!

 

I Forgot to mention. That last year I put a brand-new clutch, solid mass flywheel, quill tube, slave cylinder, master cylinder, throw out bearing, clutch fork, I rebuilt the whole pedal assembly and bushings, and I fixed the slop in the pedal. So I'm pretty puzzled as what it could be. And I don't feel like pulling the tranny out for guessing.

Also with the single mass flywheel it seems to make a lot of noise while decelerating it vibrates on my feet and is noisy enough to be noticeable like it shouldn't be that loud.

 

Sounds like the hydraulic system is not giving enough throw to disengage the trans

 

I already tried bleeding the clutch system last week. No air. No luck

 

But does it have enough throw?

 

Also a bent clutch fork or throw out bearing failing. But most likely hydraulic clutch assy is junk.

 

What fluid is in it?

 

How many miles are on your ZF ? Had mine rebuilt at 186K (synchros grinding in three gears). From my knowledge, the ZF tends to need a rebuild every 175K to 200K.

 

Fluid in the tranny ? It's the recommended fluid. There's a tag that says use only dec merk or Mercon only. And that's what I used when I flushed it. Even then it didn't help. I thought maybe with new fluid in the transmission it wouldn't grind anymore but about four months of use and it hasn't really improved.

It could need rebuilt I'm not really sure how many miles are on it. the truck shows 170,000 miles

 

ZF requires SYNTHETIC ATF for the tranny behind a diesel engine.

Measure the fork travel. It should be about 1/2" minimum at the very tip.

 

If the tranny has any run of the mill Mercon rated ATF its no wonder you and many others would have issues. If it were mine I would run Red Line MTL in it. Many folks do. Unless you live in an extremely cold climate the MTL is really good in the ZF. I would agree that you need to take a long hard look at the master / slave unit and associated hardware at the tranny. As madpogue mentions check the fork travel. Good advice there. Unless one the forks is worn internal to the transmission, which is common, you will probably be okay with a good fluid. Symptoms of a worn fork is the transmission popping out of a forward gear.

 

I just drained the tranny.

Re filled with Mercon v. Keep you guys updated.

 

Is it SYNTHETIC?

 

**** it. The suckers at napa told me that that's what I needed. Just looked at the bottle to check and it ISNT.

My fault for not checking. Have to go have a chat with them.

 

I just assumed it was. I feel like an idiot. Wasted $25 on it. $10 in fuel. And now whatever else it's gonna need.