ZF6 grinding

[Desertfireguy]

Trying to put out the feelers on this. Recently purchased a 2000 F250 4x4. Had a decent grind from 1st to 2nd and 2nd to 3rd. I'm thinking it's the synchros. Put fresh fluids in and it quieted down, but still bad when downshifting.

Question is, do I year this thing apart and try to rebuild; take it to a shop (though I don't know of any good ones in my area of NE TX); try to find a scrap one to swap in; or just sell the damn thing and try again?

Everything else on the truck is great. Currently have it listed on FB marketplace for $5900. Just not sure how much more I want to spend. Need a guru for some guidance.

 

[Pork_Chop50]

Midwest transmissions has decent rebuilts. You might also try a new slave cylinder. From what I understand there is no adjustments to make but it's remove and replace. A friend did that because his wasn't disengaging and shifted hard. Though if you are interested in selling I would like to know more. Send me a pm if you want to discuss

 

[Thewespaul]

Ive got a good rebuilder here in San Antonio that ive used. Wont be cheap but it will be right

 

[Desertfireguy]

Wes, cheap is relative. How much are you talking and what is the turnaround time?

 

[Thewespaul]

Wes, cheap is relative. How much are you talking and what is the turnaround time?

Gene Brown’s transmission in uptown SA, talk to Bert and he’ll get you a price and turnaround. Old school style shop and family owned buisness. They’ve treated me well with my Eatons I’ve sent to them

 

[greenskeeper]

What fluid are you running in your ZF6?

I've found that ATF is too "thin" and have had good luck with Pennzoil Synchromesh in my ZF6 with 255k miles on it (I run SM in all my manual transmissions).

Other things to check are as mentioned the hydraulics from the factory suck (PLASTIC slave/master cylinders).

Rockauto sells the entire slave/master assembly made out of METAL for around $100

You can also check the distance on your shift fork (known to crack and bend) by removing the slave and seeing how far the fork is from the edge of the bellhousing. A bent fork would make shifting difficult as it wouldn't fully disengage the clutch.

 

[Desertfireguy]

SA is a bit of a haul from my NE corner up here, but if it comes to it, I'm guessing they'd be worth it.

As far as fluid, I'm pretty sure I'm just running synthetic atf per manual. Don't remember brand, but I never buy cheap. I also replaced the slave/master combo. Do you know what kind of distance I'd be looking for on the fork?

 

[greenskeeper]

As far as fluid, I'm pretty sure I'm just running synthetic atf per manual. Don't remember brand, but I never buy cheap. I also replaced the slave/master combo. Do you know what kind of distance I'd be looking for on the fork?

If I recall it should be around 2.25"

I'd highly suggest giving the pennzoil synchromesh a try in your ZF6, if it is a symptom of a worn gearbox the thicker fluid could get you quite a bit more mileage out of it. Filling through the shifter makes it a fairly easy job.

 

[Desertfireguy]

If I recall it should be around 2.25"

I'd highly suggest giving the pennzoil synchromesh a try in your ZF6, if it is a symptom of a worn gearbox the thicker fluid could get you quite a bit more mileage out of it. Filling through the shifter makes it a fairly easy job.

Never thought about filling from top. Wasn't hard from underneath with my pump. I'll pick some up and give it a go.

 

[greenskeeper]

Never thought about filling from top. Wasn't hard from underneath with my pump. I'll pick some up and give it a go.

It's a cheap try if nothing else. Also the pennzoil synchomesh shifts fine even at -5F (this past week in PA) and the internal pump handles it as well.

 

[Desertfireguy]

Looked all over locally, but ended up ordering online. I'll get it in this week and post the results. Have a few other things I'm going to put on as well.