While im driving down the highway, and let off the throttle, coasting, or just m=not in it hard it will move out of 4th. I can accually watch my shifter slip into neutral. Is my linkage not adjusted correctly, I have a rebuilt shifter block, and I will admit the linkage is old, and Im sure its sloppy.

I can also move the shifter front to back about 1/4" at the shifter itself.

Any help will be appreciated...

kasey

Assuming it's not an adjustment issue, and/or the shifter body itself is loose, this is a very common problem. Usually means that the 3/4 hub and slider are worn out or the dog teeth on the input shaft are heavily worn...

MB

I just had gone through this tranny not 500 miles ago, i just havent driven it much. The block was loose on the tail shaft, Ill tighten that up, and re check the linkage. I didnt notice any wear on any parts, but Ill be honest with you guys, I did it in college like 9 years ago.

Kasey

I would suspect that you have one needle bearing missing in between the input shaft and the output shaft That or the front spring clip under the synchro tabs is broken or missing I have had tranny that would jump out of 2nd and 3rd gear but never fourth either way it is time to take it out and very carefully disassemble it, take your time and pay close attention to what is what before starting and during disassembly. EDIT, One other possiblility that can cause the trans to not stay in 4th gear is the pilot bushing That can and does cause a vibration when you rev the motor up also in high gear

Like stated above it's not usually the shifter or linkage.A worn input bearing or too much clearance on the mainshaft can cause the gears to move back and forth in the case as well.This is assuming you knew what you were looking at when you stated all the parts looked good.I usually never put a transmission back together without using new sliders and brass.You also need to look closely at the keys on the syncro hub to make sure they are not worn out too.
Gus

I bought new brass and got the rebuild kit from Brewers. I completely disassembled it, layed it out on a clean bench, cleaned and checked everything, then assembled it. Would it be noisy if I F'd something up??

Kasey

Sounds like the shifter gate is worn..
It should kind of snap from 1 gear to another gear.

Regarding linkage adjustment EZ to do..
Pull the rods out of the shifter gate, make sure the gate is in neutral. Next make sure each shifter lever (on the transmission) arm are in neutral. Then one-by-one attach each shifter rod while make sure all of the bottom tabs (shifter gate) are lined up. There should be an alignment hole in each tab, insert a drill or allen wrench to keep the tabs aligned through the holes. Carefully adjust each rod's length as required. Pull out the drill alignment/tool, EZ to tell if adjusted rite the lever will move smoothly left to rite and spring in/out of reverse.

Just my $0.015...

Thanks, Ill try that tomarrow...

Kasey

What kind of bellhousing are you using? Falling out of 4th gear can also be a bellhousing to crank allignment problem.