Overdrive Trans

LanceB

OK all, I was thinking about going with an overdrive transmission in my pickup. Right now the three speed is good for city streets but at 50 it's reving the engine up. I have a 308 mated up to the three speed. What am I getting myself into besides shortening and balancing the driveshaft?

Thanks

Park_W

OD gives you the good pickup of lower rear end gearing but still a good highway cruising ratio when in OD. If you've got the 4.11:1 rear axle now, your final will be 2.96 with the OD operative. Pretty dramatic difference. Often the biggest challenge is finding the "peripherals" ... kickdown switch, solenoid, governor, reverse lockout switch, control cable and the bracket and fittings to connect the cable to the OD tranny. Try to find an OD setup with all these things included. The other item is the relay ... if you're running 12v a suitable one is easy to find; 6v ones are getting scarce. You'll want to wire it like the '50 and later Hudsons were done. It's much simpler than the earlier scheme. I recommend placing the kickdown switch not under the accelerator but over somewhere around the dimmer switch but far enough away that you'll know which one you're punching. It's nice to be able to kick it down with your left toe whenever you want, instead of having to floor the accelerator. There are some simplified schemes floating around to eliminate some of the peripherals and wiring for a "switch on, switch off" operation, but I think it much preferred to operate it as originally installed.

Uncle Josh

Some of this stuff is available from http://www.thejeepsterman.com



You can bypass some of the stuff but I'd keep the governor in the circuit to drop it out automatically. It you forget and leave it in OD and try to back up it'll lock up and you'll have to take the tranny apart to get it loose.



Park's positioning of the kickdown switch is a great idea. You can even split shift the tranny by kicking it down with your heel as you shift from 2nd OD to standard third.

LanceB

OK, found this setup on eBay today. Just by looking at what is sitting there what do you guys think I'm missing?



http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=160208298079&ssPageName=STRK:MEWA:IT&ih=006

Park_W

Hard to see much except the solenoid and (I think) the OD control lever. I'd be a little afraid of one that's been sitting that long ... could be all rusted inside. One would think the normal coating of 90 weight oil on everything would prevent rust in storage, but my personal experience has proved otherwise.

Ol racer

Hornets have a lot of torque. If the Truck was mine and had the original transmission coupled to the 308, I would definitley change to a later model Trans with OD designed for the additional 308 torque.



However, if your 308 is coupled to a Stepdown Transmission, I would suggest to consider replacing the rear end instead with a taller Ratio (same as the Hornets Std Shift had) for more hwy speed. Startability should not be a problem with the Hornets torque...

Clutchguy

LanceB wrote:

OK, found this setup on eBay today. Just by looking at what is sitting there what do you guys think I'm missing?



http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=160208298079&ssPageName=STRK:MEWA:IT&ih=006

Looks like the input shaft is twisted??.You might ask for a close up pic of it.

LanceB

Ol racer, Is there an easy way of telling if the transmission is a late model?



Clutch guy, I will ask, a bit scared of it now though.

Ol racer

I am sorry, I know little about Std's being an Automatic guy quite awhile. I do have a '52 Std coupled to a Hornet and a '37 floor stick that look vastly different. The '52 is 20 1/2" long with 1 lever & a cable and the '37 is only 15" long. I assume '46 are similar size, but someone more knowledgable in this Topic will let you know more. Modified Hornet's would still twist the Stepdown input shaft occassionally.

Clutchguy

LanceB wrote:

Ol racer, Is there an easy way of telling if the transmission is a late model?



Clutch guy, I will ask, a bit scared of it now though.

I'm sorry Lance about scaring you.It is not my intention but just want you to know.This trans.appears to be the 48-51,single lever type.The 41 to 47 style has the solenoid on the pass.side of the trans.The picture of the trans here is sitting on the 2 wheeler,is upside down,and the solenoid is located on the drivers side.The 2 lever type is just that,it has 2 levers on the same side about 4 in.from one another.The Hudson type single lever has a 5 bolt top cover and the 2 lever-T-86e has 6 bolts on the top cover.These are a few differences.The 41-47 type Over-drive has 5 bolts that hold the rear O/D housing onto the main body of the trans..The bell housing will interchange between the 2 Hudson built transmissions[41-51]-these have -6-7/16th's bolts holding them to the trans.These bolts should also ALWAYS be resealed if you remove them.They will leak around the threads.The bolts on all earlier stick transmissions should be sealed also or they will leak.I'm sure this is too much info.for a simple topic-sorry-just get carried away.

LanceB

Don't be sorry, I was just commenting on the unit offered on eBay. I do appreaciate the information I get here, and the information about the leakage around the bolts may come in useful in finding the leak that I have on the back side there. I am still interested in adding an overdrive.