700r4 issue

[Bigredburb_Tio]

Hi I was driving down the road and my transmission and t case grenaded last year. I've had a slow rebuild process over that past year due to money issues. I've finally saved up and bought a new transmission and sourced a 241 from 88 and converted it to elctronic vss. I got it all put back together and thought that everything would work. I'm now having a problem where there is no power to the wheels unless it is up in the air. It sounds like everything it clicking in place when I move the shifters for the tcase and the trans, but the vehicle is not moving. I'm assuming since in the air it will move the back tires, that there is a atf pressure problem. Does anyone have advice on what to look for? If I can't find the problem here soon I'll just take it to a shop to trouble shoot, but I was hoping to avoid that if I could. Thanks.

91 gmc v1500 suburban 5.7

Edit---i got a new torque converter with the trans as well.

 

[Wes Harden]

hmm, with the trans in park, and rear wheels off the ground can you turn the drive shaft by hand ?

 

[Bigredburb_Tio]

I don't think so. I'm second guessing it now though. I can check tonight after work.

 

[Blue85]

A few random thoughts

• Double-check the fluid level
• You can try disconnecting the shifters and click them by hand to be sure the linkages are set right
• Do you know the history of the 241? Any chance it has bad shift forks and is sitting in neutral?
• Any chance the transmission cooler line is pinched?
• Can you hear the pump whining?
• Describe installation of the torque converter. Did it seat in nicely 3 clicks?
• Describe installation of the transmission. Did you measure the distance from the flexplate to see if you need shims?

If one of those last 2 is done wrong, you can damage the pump and no pressure = no go. Standard practice at this point is to put a pressure gauge on the transmission.

 

[Greg Ducato]

Might the 241 you used have been a 31 spline input?