Hi everybody so I'm sure many of you are familiar with the terrible overdrive setup these trucks have. Last year I decided to just say screw it and put in a toggle switch like most people probably end up doing. Within the past few years my wires that run up from the transmission tunnel into the engine bay and to the pcm have been going bad. I pretty much have the pcm 95% bypassed mine is a non ac truck and non LE truck, I took out the cruise control, the grid heater because I don't drive the truck in the winter and usually just put the block heater on a timer anyways, and everything now gets its ground from the buss bar instead of the pcm. I installed a fuse block with a buss bar in the engine bay and a 1 wire alternator. My question is about the blue ignition feed wire that comes out of the O/D solenoid and also goes to the pcm along with many other key on components, What size fuse should I put the wire on when I run a new one up from the pigtail at the solenoid? As many of you know the other one goes to the toggle switch with a ground on the other side I'm sure the ignition feed wire isn't far from going bad because last year I tapped into the O/D signal up in the engine bay instead of at the transmission and the past couple days I thought my toggle switch was going bad, but I put a new one in which didn't fix it so I ran a brand new wire up from the solenoid to the toggle switch and boom back to O/D so the wire was no good somewhere between the transmission and engine bay. Same thing happened to the vss so I ran a brand new ground wire up to my buss bar and a brand new wire from the vss to the speed signal wire in the engine bay boom speedo and odo back working.

 

With the pcm bypass there's so many wires that are just dead ends so hopefully will eventually getting around to removing all the wires I don't need once this transmission goes bad Im gonna put in a manual.

 

Swapping in a manual transmission is a common upgrade to do to these old trucks.

 

Yeah I know eventually I'll get around to it, but for now I don't have the money and I want to be able to keep driving the truck because I don't get to very much. Only went from 113k to 128k from 2020 till now.

 

Anybody else want to chime in? I wasn't 100% I hooked a brand new wire from the solenoid to a 20 amp fuse, but I guess it does need the ignition switch so I hooked the solenoid back up to it. I'm receiving 12 volts at the solenoid with the key on, but O/D is sometimes working sometimes its not like before when I flip my toggle switch. Does the toggle switch bypass the trans temp sensor? I know that can cause issues with not allowing the transmission to go into Overdrive.

 

You also have to keep in mind that the solenoid isn't always the issue.

I had my trans rebuilt because after replacing the solenoid, and powering it straight from the cab, the trans still wouldn't shift into OD. There was internal damage which prevented this from happening. You may, or may not, have something else, besides a solenoid issue going on there.

 

Alright thanks man its looking like thats the issue the only other possible thing is the plug that goes into the solenoid. Everything else is fuctioning properly tv cable is in correct spec my switch was working just fine, and the blue has 12 volts. I'm gonna try every other thing except dropping the transmission for now because if it is the internals then I'm probably just gonna drive it with 1-3 for now until it either blows up or I save up enough because I want to swap a getrag in it I'm very capable just need more money though.

 

Alright guys so like I said I'm giving it every fighting chance I can to work my way around having to spend several grand on a manual swap atm because I don't have the money. I checked voltage down below closer to the data link connector but not directly on it at the output side just above the transmission then I went back up pulled the data link connector at the rear of the engine bay apart checked 12 volts on the input side both had 12 volts. Plugged back in the data link connector and I have nothing on the output side closest to the transmission. Go back up pull the data link connector apart again and 12 volts on the input side of the ignition switch. So 100% positive nothing is wrong with the O/D solenoid, nothing is wrong with the switch in the cab, nothing is wrong with my ground, and nothing is wrong internally. I have about 95% of the transmission harness de-loomed and in the engine bay. I can't seem to find any defects in the wire so far so this is how far I am and will see what I find.

 

I'll find out tomorrow if its all fixed I guess from the factory the fuel heater, fss, and O/D 12 volt wires are tied together inside the harness then one wire goes to the data link connector. I'm hoping that the fuel heater one was the issue it'd make sense because I deleted it and that's when O/D started acting up so the connector might've been messing up the circuit for the O/D. I bypassed the data link connector and just singled out a wire from the ignition feed wire to the solenoid because I no longer need the fss or the fuel heater 12 volt reference. The pin inside the data link connector was really really really loose as well so will find out if that was part of the problem.

 

If you get your wiring sorted out and it still doesnt work/ works intermittently - i just finished a full trans rebuild to change my od solenoid (the actual solenoid on the valve body). It's not necessary to pull the trans to remove the valve body especially if you don't mind breaking the od solenoid connector because it's definitely gonna be stuck .

Anyhow they are readily available from the usual scumbags online or your local parts store can upcharge you. I paid around $30. It's a straightforward job, 10 x 7/16 bolts to drop the vb once the pan is off, remove the shift and tv linkage, park neutral sensor and wiggle the vb down till you can take the clip for the parking rod out. DONT take the rod out with the vb you'll never get it back in with the drivetrain assembled. Put some vice grips on the broken off od solenoid connector (yellow plastic that you likely broke removing the the vb because theres no where to tap it down from above with the trans in) and yank it through the hole. 2 t-25 screws hold the od solenoid to the vb.

 

Thanks for the tips bud, but sadly the clutch pack fried. I had it working again, but the last time it went into overdrive I felt something go wrong when it shifted then it came right out of gear. Usually the O/D would be smooth as butter so I could tell something went wrong internally with the last shift. It wasn't looking so good when I dropped the pan the drain plug was covered in metal and I had just serviced the transmission a few months ago, but the fluid didn't look to bad. I have the transmission out, the shifter linkage, both the coolers, all the lines, and I prepped the harness for a getrag. De-pinned a lot of stuff from the main connectors at the rear of the engine instead of cutting wires. Removed the neutral safety switch and left the two wires at the trans for the reverse switch, brought the neutral safety switch up to the engine bay and tied it by the front fender and grounded it with a new wire to my external fuse block w/buss bar I installed so the truck will start properly, I de-pinned the tps, the trans temp, wif, fuel heater, thermistor, iat, the overdrive solenoid wires because I dont need it so now I only have a few wires on the main connectors in the engine bay. Removed the 12 volt reference as well because I use a pull rope for my fuel shutoff at the lever on the pump.

 

Bummer. I beat mine up pretty bad when my TPS sensor was failing, the OD clutches weren't terrible, but my forward clutches were. I plan to go getrag or nv4500 someday, but I'll have to get all the wires out of the clutch rod hole that have been routed through the firewall. I assume you've already got pedals...

 

Yea I was afraid of that too because the tps can cause some pretty erratic shifting. Ahh that sucks do you have a lot of wires there? I think I only have 3 or 4 they're just for the trailer brakes controller that's the only thing I have left to do for the wiring, but I'm gonna wait till the clutch master and slave get here. I have a local yard that is on the hunt for the pedals for me, but if not I have a couple other ideas. He's hunting down the driveshaft as well because I ordered a getrag driveshaft, but I had failed to see that it was for the 131" (standard cab) wheelbase mine is an extended cab with the 149" wb.