got a 1999 f250 6speed and just picked the truck up and i was wondering why its hard to go from gear to gear. its easy when i push the clutch to the floor. with 163k on it what could be the problem?

 

not really sure. mine's not the greatest shifting thing ever. but its alot better since i put the new throwout bearing in. still doesn't shift as good as the old ranger did. may be just the way the old zf is. i haven't really drove any other one other than mine. but im sure someone on here will help you out

 

the zf6 gears are tight in the case right to left takes some getting used to.
Midwest short throw shifter helps ALOT.

 

The ZF-6 transmission is a german tractor tranny.... It is strong. Not to big on easy shifting though. Just and FYI out trannies use ATF and have a pump with a cooler on them so if your low on fluid OR someone put the wrong fluid in there this could cause issues. Also check to make sure your hydraulic clutch fluid Res is full to. It is the small black cylinder attached to the firewall close to the brake master...

 

I have the 6 spd as well and have been driving manuals since I start driving over 10 years ago. My truck isn't that hard to shift but it could very well be due to the fact that my syncros are mostly worn and are due to be replaced soon. I verified this by taking my truck down to the local trannie shop and the owner pulled the side panel off the trannie, looked at the gears and the syncros and showed me the slop in the syncros.

In regards to your situation there are a few things to check.
Check to see if you have air in your clutches hydrolic line. You'll have to bleed the line. Some have bled the line with the slave and master cylinder in place and some have pulled the slave and master cylinder and gravity bled them. Either way you should flush the line and get new fluid in the line. If you have a air bubble in he line you won't get as much throw in the clutch as you should.

Second, as mentioned before if you have a bad throw out bearing or if the bearing isn't centered correctly then you won't get as much throw as you should.

Also, if you're getting quite a bit of grinding between gears then chances are you have bad syncros and it is time for a rebuild. Being these are German transmissions you need to find someone that understands how to rebuild these trannies and get those replaced. A little slop is OK but if your grinding really bad, you don't have air in your clutch line and your throw out bearing looks good as well as the clutch then chances are it's a syncro problem.
Something you can try and it has worked very well for me is go down to your local napa store and ask for syncro mess transmission fluid. It is pretty darn expensive at about $15 a quart but it's a trannie fluid designed for manual trannies that require ATF. I put this fluid in my truck even though the local trannie shop said it won't do a bit of good and I tell you from my experience that it made shifting from gear to gear much nicer. Smoother shifts, less grinding, better synchronizing and quieted down the trannie so much so that the sounds I used to hear that I couldn't quite narrow down and thought it was just an exaust leak went away. I will for now on always use this syncro mesh fluid.

 

Hard shifting is 99% of the time a clutch issue.
It is not fully disengaging and that will really put a strain on the syncros.
Believe it or not, I am still running the original clutch master/slave assembly.
What I did was remove the helper spring, then install a small return spring to the clutch pedal that pulls the pedal all the way up to the top of the throw when not in use.
Then I took some baling wire (sounds redneck doesn't it?) and wrapped the shoulder of the master cylinder so that it wouldn't telescope in and out of the socket where it is installed.
That gave me the maximum travel of the master cylinder piston and it COMPLETELY disengages the clutch when I push the pedal to the floor. It will not begin to engage until the pedal is about halfway up.

 

i think it's been asked before but i cant remember if a conclusion was made.

does the clutch pedal have to be pressed to the floor for shifting or can it be just half way...is there any risk in that?

 

Typically half way to all the way to the floor, the farther the better.

 

So, what's the problem, just push the pedal to the floor...

 

The problem being that if the clutch is not properly dis-engaged then you're eating away at your syncros, just my two cents. I prefer a properly functioning vehicle as do most.

 

Uhm...did you mean "synchromesh"?

 

Yea, that's the Shtuff