I am new hear, so sorry about another over drive post. I have over drive until I give it fuel to pass or climb a hill then I lose it. Back out of the throttle and get it back. And when it happens it feels like it has hit a rev. limiter. Any thoughts?

 

Give us the year on the truck please. I had a 98 12 valve that had OD issues until I replaced the Throttle Position Sensor. (TPS)

Easy and quick if that is what you have.

 

Do a search for TPS (throttle position sensor) problems. Many times a misadjusted TPS will cause these symptoms.

 

It's a 1991.5 W250. I think I am going to get that DNR TPS delete kit. Not what I really want to do, but I am not spending $200 plus on a new TPS. I am going to check if the one I have is within specs, if not then it is gone. I am amazed how hard it is to find, and expensive parts are for these. I have had newer Dodge Cummins and all they wanted were tires and breaks. This thing has every ghost there is on the first Gens. But I do love it, it will be a sweat truck someday.

 

What you describe sounds like a kick down is working like it should .

 

It feels like its hitting the rev. limiter on a 2 stroke dirt bike. Kicks down with no go and high RPM's.

 

Maybe you are at the 2700 rpm governer. I'm just farting in the wind here but a 3200GSK might help out

 

Let me help if I can.

1. It sounds like your TPS is functioning, just mis-adjusted. You can find the adjustment procedure in the Factory Service Manual (FSM) or in the FAQ section of this forum.
2. If you need to replace it, you can delete it with a fixed resistor set, a manual pot, or a conversion to a $30 gasser TPS. All are covered in various threads here
3. What some call the kick down cable has nothing to do with downshift. It is called the TV (Throttle Value) cable, and relays the throttle position to the transmission to modify shift pressures for estimated torque.

hope it helps

 

This doesn't sound to me like a bad/out of adjustment TPS. Typically if you step down on the throttle to pass or climb a hill shouldn't an auto trans, 9 times out of 10, downshift??

 

I am going to check the TPS, was going to do it today but the couch, cold beer and Football just sounded better.

 

Marf75 I understand where you are coming from it only takes a little throttle and it all goes bad. Once the overdrive comes on, if I don't press down slowly it's gone. When it kicks down it goes flat, No get up and go.

 

When you set up to check the adjustment of the TPS, you also check to see if it is operating smoothly as it should.

The circuit is biased such that an open between the pot wiper and the resistor band it's resting on will allow the voltage to go fully high, which will effectively lock out OD. What's unusual in this case is that the open condition normally happens where the throttle spends most of it's time, thus it tends to drop out of overdrive as you're cruising.

At any rate, test next, then check your options.

 

J Martin thanks will do, when I do I will post the results. I always seem to get some off the wall problem. Funny how so many parts can mess with the O.D.

 

Not totally accurate, the cable is called a kickdown cable because it does perform a WOT kickdown or passing kickdown for the hydraulic portion of the trans. Disconnect the cable, get your trans in third and then mat the accelerator pedal, see if you get any kickdown into 1st or 2nd. You won't because the hydraulic operation has no other means of knowing where the throttle is. This is different then coast down downshifting or the low speed part throttle downshifting that occurs after slowing down for a turn or something and then reaccelerating at less than full throttle.

 

You're right about that.

The TV cable has nothing to do at all with OD operation, however. With the high torque quick through the gears operation that is normal for this setup, the shift point change doesn't seem to matter much.

If I vary the TV from default setting, I set it for shift quality, either harder or softer as desired.

OP was concerned with the TV cable causing OD to drop out prematurely.