Need an assist on this one. My 93 D350 is bone stock and just turned 94K. Owned the truck since 1998 and pretty much know it's maintenance history. Installed a new TPS about 5 years back to address a shifting issue which it resolved. Now my truck has developed a habit of frequently downshifting out of overdrive. Just went through all the connections with WD40 to ensure a good connection. Am I missing something? Thought perhaps it was time for a new tranny since the truck pretty much has been a hauler its entire life; truck camper, 5th wheel RV trailer, and now a horse trailer but think it's more of a electrical issue. Thoughts?

thx,
John

 

Look in the sticky there is a test there for the tps sensor. Sounds like a bad tps but it could also be other problems. Start there and test the tps and see what you find.

 

Problem solved, Bill thanks for the input just the same. Just retuned from a horse show and no down shifting issues. Solution: sprayed the TPS wire connector with WD40. Suspected some moisture in the connection.

While I was at it I did my annual rust prevention spraying of WD40 into the cab roof/ceiling panels using the sun visor holes.

WD40, I love that stuff...

John

 

Glad you got it fixed

 

I thought these weatherpack connectors were supposed to be weatherproof. I guess they aren't.

I have the same intermittent shifting issue. Also have had the TPS wack out in foggy weather.

Grabbing the WD40 and heading out the door.

 

I'm not sure I would use WD40 as a rust preventer. I put some on a shotgun once and it rusted just about overnight.

 

Actually, I reconsidered. I will clean the connectors with electronic cleaner, which is mostly isopropynol, and flash dries without residue, then lube it with silicone dielectric grease.

I don't know what happened with your shotgun, except that the acids from human hands are pretty nasty on fine steels. I hose down the wood splitter with WD40 and cycle it a couple of strokes when I park it. I leave it exposed in the weather with little rust.