So initial problems were transmission slipping out of first and then it locked up in 4th gear and couldn't get it out limped it home and wiggled shifter and suddenly had shift pattern back test drove it again and once again locked up in 4th

So dropped tranny removed top to find the input bearing pretty much gone so bought a full kit online , shim kit , and shifter kit.

put back together and shifted perfectly on the bench, put back in truck shifted perfectly in truck

test drove and immediately locked up in 4th

got back in shop removed shifter stub shaft and left and right shifter slides are both back and middle one slightly forward

left and right jammed tight center one will move back slightly like 1/4 " until the box is almost 1/2 made. wiggled poked pryed nothing

left it over night next day barely touched center slider and neutral box is perfect and full shift pattern back

so i know its going to lock up in 4th again i just don't know why

when i had the top off the tranny, looked at shift forks and they looked fine and nothing was done to the shifter
assembly at all during rebuild, came off and went back on in same position with tranny in neutral

can anyone help with what i might have missed

 

For neutral the shift slots need to all be in the middle

When it locks in a gear that means one of the slots is not staying in the center, when driving in this case

Center slot/shift rod is 3rd back, 4th forward, so it was in correct position when you pulled shifter out

Left and right slots, "were back"?
So not in the center?

Did you get a chance to try Reverse in the test drive?

 

used reverse to get out of garage

can't figure out how i'm getting the sliders to stay in the pattern they are in when it jams

Am i right that left rod is in 1st and right rod is in 3rd and middle rod is just neutral

if so i'm confused as to how it is shifting from 1st to 2nd and then to 3rd and not leaving the the 1&2 shift rod lined up with neutral

 

When looking down from the top of the trans, the rod on the right is 1-2, middle 3-4 and left is 5-R

Rods move backwards for odd gears, and forwards for even gears.

The shift rail system is really only responsible for moving the syncro collar into engagement, the syncro unit as well as the gear and dog/engagement teeth are what hold it in place while moving.

That being said, it sounds to me like you have a bent shift fork or worn/broken shift assembly, Which can be one of the following components

Shift shaft
shift rail
shift fork
syncro hub
broken/worn dog teeth

I presume since you said you rebuilt it at home you replaced all large bearings and all races as well? 4th is a "hard" 1:1 connection that just locks input to output, so if there is enough play on the pocket bearing/output shaft bearing sleeve, then it can cause a misalignment and thus lock into 4th, mechanically.

 

Touris thank you for straightening me out on the shift rails I should have been able to get that one straight but my mild dyslexia got in the way

Yes i completely rebuilt tranny all new stub shaft kit , new syncros, bearings and races, however i added shims at front of input could this be causing binding of input to output if the shims were too much

the shift forks and rails all looked fine and when the shift pattern is there everything shifts like butter so i'm leaning to the problem being with alignment to 4th and the input shaft

all gears looked new and hubs were also in good shape

would it be normal for the 4th to lock up only when under load due to miss alignment, and its not likely i will be able to recreate the same scenario on the bench?

 

Yes, if the issue is boiled down to a bad race/output shaft/worn input shaft pocket, that would really only rear its ugly head when a load is applied.

The input/counter shaft shims would cause a bind, but this should be more noticeable as a tight free-spin, when you rotate the input shaft or output shaft by hand. All they do is adjust end play to the two conical bearings, and unless you added an outrageous amount of preload shims to the input shaft cover, shouldn't really effect anything.

FWIW, I "added" a slight amount of preload to mine when I rebuilt it this spring, as I know the races will wear in a little bit with the first few 100 miles or so. I really don't feel like rebuilding it again, but if it would need it, should be around the same time the rest of the truck falls apart

 

thank you Turis and RonD for your help I guess i'll be dropping mine out tomorrow and checking clearances again.
It gets easier every time i do it!

So i dropped tranny again and redid specs and calculations on end play of input and counter shaft removing shim



HOWEVER AS A NOTE TO ANY OTHERS

when i removed the tranny cover for one last inspection i must have bumped the stick shift into 4th it must also have been after the shift forks had cleared the chanal on the shift hub slider
this allowed the center shift rod to over extend to the front of cover allowing the detent pin to escape. Luckily it stuck in oil on the inside of top cover as i turned the cover over or would likely have ended up down in the gears and would never have been noticed until to late. likely causing a catastrophic failure!

ALWAYS KEEP SHIFTER IN NEUTRAL especially when shift forks are not limited by shifter hub channals

 

putting tranny back in today hopefully i have it right now

once again thankyou

 

Good luck and good work

 

So far I've had to pull my trans 6 or 7 times since I've owned mine in 2011. It does get quite a bit easier after you've done it once or twice. I have the process down to a science, practically.