3 Speed Overdrive Problems

[west_pa]

Hi all. I was wondering if anyone knows a source for troubleshooting a 3 spd overdrive system. I have a 70 F-100 with the 3 spd on the column and overdrive. When you push the overdrive knob in, the only difference it makes, is that it free wheels when you let off the gas. I checked the fuse on the relay under the hood, and found it wasn't making contact. After fixing that, it started blowing fuses. Then I found bare and broken wires going into the solenoid on the transmission. I took the solenoid off, took the housing off, and soldered new wires into it. Now, when I turn on the key, the relay clicks under the hood, and the solenoid on the transmission sometimes clicks. When it doesn't click, it draws enough juice that it dims the dome light a lot. When it does click, the relay clicks first, then the dome light dims for a second, then the solenoid clicks, and the dome light brightens back up. If you push the kickdown switch under the hood, the relay and solenoid click, then when you release it, it does the whole dimming of the lights, solenoid click, brighten up again. I was looking at an old Chilton book that was for cars in the 60s. It showed a wire from the coil going to the kickdown switch I believe. I don't have a wire doing this. Also, the wire on the governor appears to be bare where it goes inside of it. Don't know if that could be an issue or not, as I think it is a ground wire anyway. Any help anyone can provide would be GREATLY appreciated.

[AlleyCat]

I'd suggest taking a closer look at that wire on the governer.From your description the system has a short circuit and the governer may be it.I also have an old Chilton book that shows the same circuitry.The 50's Motor book I have has better pics of the gearing but no diagram.I have to go to my folks house today and I'll see if my dad has any info in his collection.Hope this helps.

[west_pa]

Thanks for the info. I am going away this afternoon, but hopefully will get a chance to look at it again tonight or tomorrow. Any other pointers from anyone?

[fmartin_gila1]

Go to Yahoo group Ford Truck 1900-79 List. In the files section is a downloadable OD (Overdrive) manual that covers this unit.
Fred

[MaxKlinger]

Is this a three speed with overdrive in the sense that it's a 4-speed? Or is it a second transmission box that provides 1:1 or overdrive? Is this an aftermarket installation?

[AlleyCat]

Is this a three speed with overdrive in the sense that it's a 4-speed? Or is it a second transmission box that provides 1:1 or overdrive? Is this an aftermarket installation?

It's a 3 speed trans that 3rd gear is 1:1 ratio but it has an electromechanical gear set in the tail housing to provide the overdrive.At one time these were fairly common and most O.E.M's used them.You could drive with the OD engaged or lock it out and drive it as a normal 3 speed trans.I believe the Borg Warner T85 was the most common.Good for gas mileage.Hope this helps.

[MaxKlinger]

Is this a three speed with overdrive in the sense that it's a 4-speed? Or is it a second transmission box that provides 1:1 or overdrive? Is this an aftermarket installation?

It's a 3 speed trans that 3rd gear is 1:1 ratio but it has an electromechanical gear set in the tail housing to provide the overdrive.At one time these were fairly common and most O.E.M's used them.You could drive with the OD engaged or lock it out and drive it as a normal 3 speed trans.I believe the Borg Warner T85 was the most common.Good for gas mileage.Hope this helps.

I didn't know that, that's pretty cool. Thanks!

[fmartin_gila1]

Did you go to that site and download the manual? It covers everything about it, Operation, Maintenance, troubleshooting, & overhaul. I downloaded it and printed it out, just for possible future reference, even though I have put a T5 in mine.
Fred

[fmartin_gila1]

MaxKlinger,
This OD setup was available as an option on most all vehicles in years past. I don't remember when it stopped, seems maybe in the mid 70s. It had freewheel in all forward gears when in OD, which meant there was no compression braking. This lead to it's downfall(our gov looking out for us).
These were followed the 4th OD or 3 + 1 that you are prolly thinking of, these ran well up into the 80s or possibly even the 90s, don't remember.
Fred

[west_pa]

Thanks for the help guys. I did download and print that manual. I haven't really had much chance to get back to working on it though. The day I was going to work on it, something else came up. The aftermarket radio isn't wired through the switch. So. it ended up getting turned down, but not off. That ran the battery dead. It also killed the battery. I charged it for 2 days, then took it to be tested. They told me I had 3 cranking amps. It just wouldn't charge back up. So, now I have a new battery. I also eliminated an aftermarket manual temp gauge, and hooked the original one back up. I have a whole box of parts from LMC just waiting to be put on (oil sending unit, vent window seals, anti rattlers, fuzzy window tracks, dash lens, hood springs, etc). Now I just need the time to get it all done. Someone told me that the relay for the overdrive shouldn't click as soon as I turn the key on. It should only click and engage the solenoid after it's up to speed to kick in the OD. I unplugged the governor, and it stopped clicking when you turn the key on. Maybe the governor is the issue?? I'll keep you guys posted as to what I find out when I get back into it again.