I wouldn't do this. I think the actual market value of your truck is a lot less than $2,500, and with 170k on the motor I wouldn't put $1,000 let alone $2,300 into it.
If you have friends or family who are skilled mechanics able to replace the transmission, that is the only scenario in which I'd think this is a good idea. I'd figure on finding a transmission from a salvage yard for under $1,000 (hopefully more like $600) and installing it for a case of beer. :)
Otherwise I'd put $1,000 - $2,300 into another used vehicle instead of propping this one up. You're ready for an engine overhaul too.