That should be pretty straight forward right? hmmm maybe not. Any one done it before? Id throw a floor shifter in.

 

The computer system would throw you off. Lots of wires, plus an entire pcm for it. Im bout to throw a Getrag in mine.

 

I thought the module just controls the overdrive. A switch on the dash could handle that from what I've read here. You do have a crossmember and drive shafts to deal with though.
Ryan

 

Oh okay. Are the crossmembers different?

 

I don't think the crossmember is different but it sure appears to be farther back on the 518.I'm sure somebody will chime in that knows.
Ryan

 

If anything, you may just need the trans mount from the 518 along with the tranny.

 

Hmmm... thatd be cool, a switch to control overdrive. Im sure something could be rigged up, no need for a temp switch to diddle with. Im really curious about this now. If some one could measure tranny length, n compare cross members thatd help a lot. Heck I bet a conversion like that would be very popular. Maybe even a sticky! lol

 

This is my second try for a post on this thread. My computer or my computer skills are lacking.
When I upgraded the TC, flexplate and valve body, it was suggested to me by Tim to upgrade to a 47rh. They handle more torque than a A518 and you have the advantage of a lockup. I was stubborn and cheap so I stayed with mine. The A518 is longer than the 727. The od unit was added between the tailshaft housing and the tranny. It is actuated by a solenoid valve in the valve body which is switched on the ground side by the PCM. We had a little trouble with mine when we did the valve body so I put a switch in the cab to make it work until I could get it in the shop again to fix the wire. It worked just fine manually. The o/d cannot be engaged unless the tranny is in third. Something about the way fluid is channeled thru the tranny.

 

I would do the shifter OD button from a 94'-up and not worry too much about it. The only real challenge would be if it was an early 2wd, the tunnel is smaller. Compare one to a 4wd trans tunnel some time you'll see what I mean. If I am not mistaken the later trucks (91.5'-93') came with the larger square 4wd tunnel.

 

I've done it........I took out a Getrag and put in a 518...I wanted and exhaust brake so I then took out the 518 and put in a 47RH. You just need one simple switch to send a ground signal to the o/drive solenoid to turn it on when you want it on the 518. You will need 2 on a 47RH(one for overdrive, and another for lockup. If you are contemplating a 518, by all means I recommend the 47RH!!!! The lockup torque convertor is far superior than a non lockup tranny.