Can’t suck Thru transmission lines

[Daniel8772]

Hey guys I recently picked up a 4l80 for my 91 Chevy and it did work with the guy I bought it from but when i installed it I seen the tail shaft spin to verify it was good then when I bolted the trans case and drive line up it did absolutely nothing,

so I went to see if it was pumping fluid and of course it wasn’t so I verified it was full and it was but I didn’t give up there and I ended up checking the line and I ended up sucking on the lines and I couldn’t suck anything thru at all, I even tried to blow thru it and can blow if I tried hard enough I can kinda blow thru what would cause this I’m stumped

 

[Erik the Awful]

I'll ask the silly questions first. How do you know it was a good transmission, did you see it run? Is the fluid level correct? Did you get three clunks from the torque converter when you installed it? Did you put the flexplate bolts in and loctite them?

 

[Daniel8772]

I seen the trans actually moved with my own eyes so know it was good before
I installed it and I actually filled
It up and ran with everything but the drive line attached just to double check and it in to gear and spun but when everything got final assembly it quit,
The torque converter isn’t new so I’m wondering if that crap out but it is full of fluid and I couldn’t suck thru the Line at all and it just got me stumped

 

[Erik the Awful]

Fire it up and shift it through all the gears, all the way down to 1, then back up, pausing a few seconds in each gear. Then check your fluid level again. Repeat until the fluid level stays good.

 

[Daniel8772]

Fire it up and shift it through all the gears, all the way down to 1, then back up, pausing a few seconds in each gear. Then check your fluid level again. Repeat until the fluid level stays good.

I’ll Have to go try that, now if that doesn’t work what else could I check because i still can’t get it to go in gear or pump fluid thru lines

 

[Erik the Awful]

If you do that and it's not pumping fluid and you know the torque converter is all the way in and all the flexplate-to-engine and flexplate-to-torque-converter bolts are tight, then the oil pump in the transmission isn't pumping.

 

[red97k1500]

You might have broke the front pump from not having the torque converter all the way stabbed.