Turbo 400 issues

[JFORRESTERSR]

Ok so I am sorry this is lengthy but i an at my wits end and need some help
this has been a 4 month long situation. So my 72 k5 has a turbo 400 in it that was slipping, it would slip while sitting at a light then pop into gear the second issues was it would slip out of gear and jump back and forth from 2 gear to neutral while diving at a slow speed (usually between 10-20 but after 25 it was fine once it was in 3rd gear.
So I find shop near me and have them rebuild the trans that was 4 months ago got it back and the sifting was fine and no more slipping at a stop
however the slow speed in and out of gear is still happening and it seems to happen after everything gets hot
and heres the laundry list of things the trans guy has done
2 modulators
tried regulating the vacuum
new valve body
checked & changed governor (used)

hes is a nice guy but i need to figure this thing out I live in florida and love to drive the beach and this in and out sucks
any help is greatly appreciated

[kwmech]

may be something in the valve body sticking. Maybe Clinebarger will chime in

[AussieinNC]

This has all the signs of low oil level in the trans....add a quart of ATF and try again....

I have seen aftermarket dipstick tubes and dipsticks be out of specs resulting in issues.

I have also seen an ill fitting trans filter creating an air leak into the pump housing..causing pressure issues....slow gear take up, poor shifting etc...

I suggest you change the filter and make sure there is a O ring on the tip of the feed tube that fits into the pump....

Does this trans have an aftermarket deep pan? The original pan has a dimple on the bottom of the pan to keep the filter in contact with the pump....plus there is a bolt thru the filter body to retain the filter...

Finally, make sure the detent comb is not holding the manual valve in a misplaced position....while the pan is off, check that the drive position of the gear lever equates to the detent spring being in the middle of the D comb position....

[JFORRESTERSR]

Good Morning All
ok some more background and follow info
this a trans shop that is doing the work (perhaps not the best) and its the original trans including the dipstick tube
he rebuilt it in june so I assume its a new filter but I will confirm
he is now thinking because the issue happens after it gets hot it my be a seal or sleeve inside.
I am just hoping someone has had this same thing happen and
knows the reason and its something very uncommon

thanks

[clinebarger]

I would go over the Governor circuit really well after verifying fluid level.

The Governor Stem lands are .800" nominal.....Much under that is worn out. Governor end-play should be .060"