87 R10 lq4 help

[zach_carver]

I'm looking for some guidance. I have a 87 chevy r10 we've swapped a lq4/4l80e into. Truck is crammed btr stage 4 truck cam, and circle d stall. Truck runs great, idles good and all is well. However truck wont move in any gear. We've now had two different tuners look into segment swap and all. Range sensor has been removed from tune also. You guys ever heard of seen anything similar? We've replaced the harness in trans, and we've added another ground to transmission also.

[mongocanfly]

Was trans good before the swap?....

[87chevy.com]

If you installed the torque converter and ot wanst seated all the way in, chances are you broke the front pump.. super common if you dont know.... I'd imagine a quick test is to disconnect both fluid lines at the cooler and see if fluid gushes out when the motor is cranked over and running..
Atleast that's how I'd imagine testing of the pump is broken
Clint

Usually when a tuner fant figure it out, it's a mechanical problem

[Big Moose]

^^^What he said. Another thing you could do is hook up a gauge and check your line pressure

[zach_carver]

Truck has made s one mile drive perfectly. But it was right after the segment swap was done in tuning. And it only lasted maybe one mile.It doesn't have any gears forward or backwards. I guess we could pull one line and see what fluid comes out. It was supposed to be a 80k mile motor and trans that operated perfectly when pulled.

[BR3W CITY]

Is the trans from the same donor? There are two wiring configs for the 4l80e pre ~97 and after. The trans harness, main harness, and tune need to be setup for the same stuff. Usually replacement harnesses are made for the "new" configuration, but its worth noting if your chasing wiring problems.

If it ever worked at all then the tune isn't the problem. Trans tuning can't cause intermittent issues, unless something in the trans being commanded is SO off that it causes a limp condition.

Didn't see you mention if any codes were being thrown? (including t- or u- codes).

[zach_carver]

It was throwing a range sensor code before the second tuner tuned it out I think was po706. I havent scanned it sense to see if it has any new DTCs. Ill scan it and see what it says. Were using a PSI harness, but yea motor/ trans were from the same vehicle but ecm wasnt from same vehicle.