VSS , Speedo , Potentiometer question
 

I bought a new to me d350 single wheel last weekend and have been fixing the po repairs all week but I have a question about the tps potentiometer swap , I had a potentiometer on my last truck so was planning on doing this one but the speedo dont work and it did on the previous truck , question is does the speedo have to work to do the potentiometer for the o/d to work ? , The guy couldnt fig. out th o/d so I had to buy it bec. the price was right and it only has 158,000 miles , I did put in a vss and still no speedo , The speedo did work on my drive home then just dont the next day ? worked just fine no bounce or anything now nothing.

Sound's like maybe a gear went out in speedo and yes it must work for OD to work also

Thanks for the reply simplysmn but I want to clarify , I know the overdrive only works through the tps using the speedometer and vss but will the overdrive work using a potentiometer without the speedo working ? Need overdrive asap and will address the speedo later , Thanks

I want too say you need speedo to do both

Check the Speed sensor (Distance Sensor) wires to see if they are rubbing the drive shaft. Mine was and rubbed thru the insulation and the Speedo would not work when they would bounce around and fall down on the driveshaft.
Also for a temp fix for the OD. There are 2 wires on the Trans that go inside to the OD solenoid. One wire has 12v at all times, and the SBEC sends a ground to the other when it is to go in OD. I ran a wire from that wire on the trans thru the floor inside the truck and stripped back about 2" of insulation off the end in the cab and hooked it on the gear shifter shaft... it supplies the ground signal and goes into OD till I can get it fixed.

Hook the wire on the shifter when you are ready to go into OD and unhook it when you slow down below 40 mph or so. It will not hurt any thing if you forget to unhook it... I have forgotten several times.

It also is designed to not allow OD when Eng Temp is cold or Trans Fluid is above... I believe 273 degrees.

Thanks ricky0677 , I did the ground switch like you said just to get me by and works for now till I have time to chase wires.

Glad it worked. At least you know the trans is fine. You sure don't waste any time getting to something.

Had to fix it or band aid it asap I live 20 miles out of town and its 65 mph till then , almost was ran over a few times yesterday but all good today , Also installed my Diamond Eye 4" exhaust with no muffler and all I can say is OH YAH !!!!!

If you have time after you find out what your problem is, post it. Just curious.

Will do ricky , going to be a bit , I have a few too many irons in the fire , as soon as i figure it out ill post it up.