Trans problems

[NyCowboy87]

Have a good friend that bought a truck a while back that had been built about 3 owners ago. When he bought it the engine was out because of 3 broken rockers and the previous owner knew nothing about a 7.3 and thought it was blown up. Long story short we went through it, put the engine back in and got it going. Truck runs awesome (full built engine, swamps old 390/200s, sledgehammer turbo etc.) now on to the trans issues.
The trans will not shift unless you let out of it, you can shift it manually and it shifts fine. This is supposed to be a full built suncoast, so I called them sat on hold for 20 minutes to talk with the guy and told me nothing. I put a snap on modis scan tool on it and watched to see if it was telling the trans to shift, it was. Also checked for codes and found none, so I'm kind of stumped. I pulled all the connectors apart to check the pins and everything looked great, put it back together and still have the issue. This is a e4od trans in a 95 truck, any ideas?

 

[Dieselboy.]

I'd guess valve body. My 4r in one truck will occasionally hold first out until I either let out or go wot. I've replace sensors and fresh fluid. Time to drop the pan and see if some stuff is in there and gummed it up ??

 

[golfer]

Have a good friend that bought a truck a while back that had been built about 3 owners ago. When he bought it the engine was out because of 3 broken rockers and the previous owner knew nothing about a 7.3 and thought it was blown up. Long story short we went through it, put the engine back in and got it going. Truck runs awesome (full built engine, swamps old 390/200s, sledgehammer turbo etc.) now on to the trans issues.
The trans will not shift unless you let out of it, you can shift it manually and it shifts fine. This is supposed to be a full built suncoast, so I called them sat on hold for 20 minutes to talk with the guy and told me nothing. I put a snap on modis scan tool on it and watched to see if it was telling the trans to shift, it was. Also checked for codes and found none, so I'm kind of stumped. I pulled all the connectors apart to check the pins and everything looked great, put it back together and still have the issue. This is a e4od trans in a 95 truck, any ideas?

what gears/tire size are in the truck

(thinking tuning/shift point issue)

does it shift better/normally w/o the chip?

 

[NyCowboy87]

Had the pan off to replace the filter and fluid before we even started the truck and it was squeaky clean.
It has 305/70r16's on it with stock gearing as far as I know, I believe they are 4.10s. I have not yanked the chip to see how it shifts on the factory PCM, have to give that a shot.