91 auto 4x4, wont shift out of low gear. What auto trans?

I picked up a 91 D50 4x4 4 cyl with auto trans, The kid took the trans out to put a front seal in and upon putting it back in it wont shift out of low gear. He threw towel in. I was going to use it as a shag track around the farm so I can live with it but if it is something I can address without a full trans pull I would be up for it. Can anyone advise what auto trans this is and what common platform it may have also been used in?

That was the issue. It was pulled tight and that was keeping it in low gear.