Need help. Lost OD AGAIN, about to sell the truck...

[oldestof11]

So today has not gone well at all. This is the pinnacle of the mountain of chit that I have had land on me today.

Coming home, going down the interstate from a city 40 miles away, I was cruising at 75mph. All of a sudden, OD kicked out and back in. It continued to do this for the next 15 miles where I got off. Check fluids, 1 qt low while still in the safe area. Checked in neutral. I noticed the voltage would fluctuate between the 2 normal lines. It sometimes kicked out when hitting a bump. Didn't matter the throttle position or speed, it would go in and out at random. Sometimes I could pull a hill accelerating, sometimes I would go 45mph for 2-3 miles. I think the AC was also doing this but it is cool here and I got cold quick.

I get home, add a quart of fluid so it was at the full mark. I go for a quick drive. I start accelerating from 30mph to 60mph. It shifts like normal and holds 60 for a quarter mile. Then it goes out completely for the 6-7 mile ride home.

Fluid is a mix of ATF and tractor fluid. I did notice on the couple hills I was able to accelerate, OD felt weaker than normal. Fluid looked ok but it is dusk here and I don't trust my eyes in dim light.

Also in its last 150k miles, it has not had a rebuild. I have had it for 30k miles, the owner before had it for 120k miles. The owner before him never mentioned a rebuild.

PCM, Crank sensor? OD gone? I will get my fluke from work and OHM out what I can.

[ellis93]

I'd say the crank sensor....especially if the ac and alt were acting screwy too.

Those trans are cake to build Jon. If it needs it after the computer gave it hell....don't shy away.

[oldestof11]

What should the crank give? I'm assuming a 0-5v reference?

[ellis93]

I think there's a test procedure on the sticky over on diesel truck resource Jon.

[oldestof11]

Put on my TPS delete. No change so its not the TPS.

Truck is charging at the high line of normal range lines. It does it occasionally.

Found this. I'm going to splice it and shrink wrap it. Hopefully this is the issue.

[oldestof11]

That rubbed through wire did it. I cut, spliced, shrink wrapped, and rerouted the OD wires and can now hit 100mph quite reliably.

[PToombs]

Good job Jon! By the way, Happy anniversary, you have been here 8 years today.

[oldestof11]

Dang...

[PToombs]

HAHAHAHA, time flies when you are getting abused huh?

[oldestof11]

I stick around so... I like it?:lol:

[fatty]

What's this about selling the truck?? You might not be allowed here anymore.

[oldestof11]

It has been a hell of a weekend since Thursday. I was ready to become a monk before today.

[PToombs]

I was ready to become a monk before today.

You don't want to do that, wacking it gets old and makes it go around corners. BTDT.

[oldestof11]

So headed to work today, OD wouldn't kick in until 60mph. Then it kicked out and wouldn't do it till 65mph. So I get to 5 miles from work and I lose it again. This time no OD until 70mph. So I do 55mph for 5 miles on direct. I threw on my potentiometer and now it works as it should...

BUT....

I thought with a Pot, it shifts at whatever MPH you set it for. However, light throttle, it shifts/drops out at 42mph. Heavy throttle and it doesn't do it until 65mph, like the TPS did. Only thing that is different is the TPS would shift/drop OD around 35mph where as the TPS does it at 42.

WHAT AM I DOING WRONG?!?!?!