I have a 1995 F-250 Powerstroke with the ZF-5 manual trans 4X4. I rebuilt the trans (syncros, seals, some bearings) about 2 years ago, now the 2nd gear synchronizer has already gone out. It had difficulty going into reverse and 5th sometimes like it was locked out. Now the 2nd gear synchronizer just quit this weekend. I used a trans rebuild kit from a transmission shop here locally they had to order of coarse it cost $450.00+/- I think. Has any one heard of any problems or special kits to use? Looks like I will be taking it back apart this year. Thanks for any input.

 

Well thats a bummer that you have to get back in that thing,

Now a couple things come to mind to explain premature syncro wear,

#1 on least the older Fords with the 7.3 l eng the fire wall flexes and the clutch does not fully disengage, there are kits available from Ford to reinforce the Fire wall where the master cly bolts on,

Easy to see just have some one push in the clutch while watching the fire wall from the outside, you will see it flex, sometimes the fire wall even cracks,

#2 Make Sure the clutch and input splines are well lubed with a grease, some clutch kits come with a lube for the splines others dont, the Clutch disc actually needs to slide on the input shaft to fully disengage,

So the look to the clutch system as the cause of your trashed syncro rings,

 

Another thing we see is drivers that rest their arms weight on the shifter all the time.. It will cause the shift forks to actually wear, or wear 'through' in severe cases as well as wear the synchro's out..