i would just like to say thank you for all the great info...i've been trying to figure out my t-85. it is the original engine and tranny but most(if not all) of the parts to make it work are gone. it also wont go into first gear and it doesn't like to go into third. there is a lever that is wired to the frame(i assume it is locked into overdrive?) and i also have located the overdrive relay. my question is could you tell me where the kickdown switch is located? also i would like to make my system work and if somebody could explain which wires to run to the toggle. i am about the worst at wiring so if you could explain it like your teaching a 10 year old i would greatly appreciate it. also has anyone put new syncros and busings in a t-85 themselves? a local tranny shop said labor and parts would be about $300. thanks again

 

>>Does the T-85 have a syncro in first? <<
No, it doesn't.
>>And when the power circuit is completed to the solenoid it then shifts to OD and goes back to direct when the circuit is broken(and the torque released) is that correct.<<
You are correct; it doesn't matter what gear you are in when the OD kicks in. I am trying out a 2.75 chunk in my rear end. Just for kicks and giggles, I got it up to 32 MPH in 1st gear and the OD kicked in. The engine was screaming, though. Not recommended!
>>And do you need to pull out the lockout for it to set on a hill?<<
Only if you do NOT put it in Reverse, or, for using the engine as a brake at lower RPMs. .
>> Can you park with it in reverse with out it rolling. <<
Yes. The OD is locked out, and it functions as a regular transmission that way. I recommend you get in the habit of ALWAYS putting the truck in Reverse whenever you turn the key off.
>>It has been 20 years since I was around one and I can't remember all the details of operation.<<
Ah, um, can't help you there!
<<Also do an internet search for borg warner t 85 and you will find a site with pictures and diagrams of a guy who has made his all manually operated with 3 switches and 2 relays. <<
Yes, he did a really great job on that site.
Hope this helps!

 

Maybe you could put the momentary ground button in if you want to use OD with first gear, to bypass the governor.
Wow a 2:75 cog with overdrive! That comes out to about 12 final drive in od. If my calculations are correct you would be turning just under 1300 rpm at 60 mph with a 30 inch tall tire.
I test drove one of those overdrive 4 speed F-100s around 1980. I think it had a 255 engine but it may have been a 302. I shifted it in to 4th(od) at 60 mph on a long straight away and mashed the pedal to the floor. 1 1/2 miles later I was still going 60 on flat ground. I think that pickup had a 3:00 cog or a 3:25. I didn't buy it. On the same note, I have an 88 Gran Marquis and a 98 F-150 S/C both with 302 and automatic. Neither of them can go up a grade without shifting down. You get to a hill and just keep pushing the pedal until it is around halfway to the floor and then down it shifts with a lurch and a roar. Very annoying, but that has nothing to do with what you are doing.

 

This is an excellent thread! Thanks guys, I'm going to bookmark it.

barry

 

>> I've been trying to figure out my t-85. it is the original engine and tranny but most(if not all) of the parts to make it work are gone. <<
Most of these parts are available on E-Bay, believe it or not. You'll need to keep a constant watch, but they can be found. Keep in mind that a GM part may not look identical, but if it is for the OD, it will probably work. Don't forget to check closely at the boneyards for parts.

>>it also wont go into first gear and it doesn't like to go into third.<<
Sounds like shift linkage problems more than likely. Misadjusted linkage, worn or missing bushings, rusted out cab mounts - all will cause this.

>> there is a lever that is wired to the frame(i assume it is locked into overdrive?)<<
The lockout feature is to PREVENT the OD funtion from working. Most people assume (incorrectly) that pulling the cable out (pulling that side lever forward) activated the OD, when in fact it does just the opposite. Check the position of yours. If it is wired in the forward position, then the OD funtion is deactivated. Another indicator is if your truck freewheels. Get up to about 1200 RPMs in 1st gear (don't blow the motor!) Take your foot off the gas. If the engine brakes the truck, OD is locked out and is not working. If the engine drops to idle, and does NOT brake the truck, but the truck keeps rolling, then the OD is freewheeling. Until you get your OD unit working, I would leave the lever in the forward position, for safety's sake

>> and i also have located the overdrive relay. my question is could you tell me where the kickdown switch is located?<<
On my '66 this switch is on a bracket located above the acclerator. The top of the accelerator lever touched the kickdown switch when it is pushed to wide open throttle. It may be different '67 - '72.

>>I would like to make my system work and if somebody could explain which wires to run to the toggle. i am about the worst at wiring so if you could explain it like your teaching a 10 year old i would greatly appreciate it.<<
Explaining a complex wiring project by e-mail is almost impossible. Pictures or on the spot advice is really needed.
If your wiring harness for the OD are gone, you would be best to find used harnesses, or to follow/adapt this wiring diagram:


>> also has anyone put new syncros and busings in a t-85 themselves?<<
I have never done it, nor had it done. I would check your linkages first. These transmissions are tough and durable, so I doubt yours needs work.

 

>>Maybe you could put the momentary ground button in if you want to use OD with first gear, to bypass the governor.<<
Good idea, but you would have to hold the button in to keep it in OD. That ground from the governor activates the relay, which supplies power to the OD solenoid to make it work.

>> Wow a 2:75 cog with overdrive! That comes out to about 12 final drive in od. If my calculations are correct you would be turning just under 1300 rpm at 60 mph with a 30 inch tall tire. <<
Yeah that's about right. It is definitely TOO tall.

I would like to find a 28 spline 3.00 or 3.25. I have a 3.00 with axles out of a '76, but it is 31 spline.

 

thanks for the info...the truck doesnt freewheel so that is fix #1. also i have checked the linkages before, all of the bushings are there however they are very worn. my truck is almost rust free so i know the cab mounts are good...i have another question if you dont mind...if i pull out my solenoid out and put 12 volts to it, will it pop out? i would like to trouble-shoot so i know what parts i need. i think thats all i have for now.

 

To check the solenoid, ground the outside, and touch one wire to power.
One or the other will activate it! - and yes, it will pop out.

 

When using a momentary ground to split first gear, wouldn't it stay in o/d until you let off the gas? By then I would think you should be above 28 mph and the govenor would take over.

 

And to think I got the whole truck the other day with one of these in them A 69 with a 390. Going to install cab and wiring on his truck, First time seeing one myself GWB

 

>>When using a momentary ground to split first gear, wouldn't it stay in o/d until you let off the gas? By then I would think you should be above 28 mph and the govenor would take over.<<

Now I see what you are doing. Yes, that's correct, but there really is no need for that. I never have wanted OD in less than high RPMs in 2nd.
The ratio in OD is about .7, and at less than 30, I jsut don't see any advantage - unless you have a long drive at 25 MPH.
But yes, you could use a sepatate ground for the relay to activate the system.

 

I wouldn't know if there was a need for o/d in first or even second for that matter under normal driving conditions, but I may pull a small vintage travel trailer with the car at some point so I am just thinking of possibilitys and I saw on the aformentioned website the guy had that momentary switch provision for splitting first.
I am not sure on a Ford but I seem to remember that on the old chevys second and over was actually not much lower than third direct, so first and over may end up being so close in ratio to second direct that you would never use it anyway.

 

And a lot depends on the rear end ratio as well. You might get some value out of splitting 1st if you had a 4.x rear, but definitely not with a 3.5 (which is what my truck came with) or taller.

 

I am pretty sure the rear end is a 4:10 but I haven't actually checked it yet.