3 speed manual overdrive

[ol Curt]

Anybody have one that works, and if so, how well?

I see them advertised for tri-five chevys occasionally. Would those fit our trucks?

[protrash64]

There was a thread on here with a bunch of info about the conversion. I dont remember the name of the thread.

[ol Curt]

I'll keep searching...must not have hit on the right combination of search terms yet...at least i know there is one here!

Thanks!!

[protrash64]

Here's what I was thinking of ol Curt.http://67-72chevytrucks.com/vboard/s...d.php?t=313886

[ol Curt]

Thanks,

I'll read through that closely. AM i understanding it correctly that if you could find the electrical part, it would mount to any transmission and that you wouldn't necessarily have to find a transmission with the unit on it? I sthat how you read it?

[protrash64]

Curt...I read through this whole thing again and I cant tell. I'm not familiar with these things at all. I dont know if you need the whole tranny, or if its the 'tailshaft' piece with the big solenoid canister on it. I believe some of the conversation was about just how to engage the system.

I'm wondering if it is like a GearVendors unit. I have also recently read an article in Classic trucks mag about a 4spd overdrive from the 80's that was not widely used. I think it was mostly in Chryslers, but it was used in GM app's as well. I'll see if I can find that article....mite be another option.

[MikeN]

Originally Posted by ol Curt

Thanks,

I'll read through that closely. AM i understanding it correctly that if you could find the electrical part, it would mount to any transmission and that you wouldn't necessarily have to find a transmission with the unit on it? I sthat how you read it?

No, this is incorrect. An OD transmission with have a different tailshaft extension housing, with an electric solenoid actuator, a governor, a cable operated override actuator, and the actual planetary gears.

The 55-57 passenger car 3-speed OD can be adapted to our trucks pretty easily. My brother-in-law has done it on his 65 C10.

[protrash64]

Here's the other article I was thinking of.....interesting, http://www.customclassictrucks.com/t...ion/index.html

[1Bad62Pro/Street]

What about a Muncie 4 speed transmission!
Muncie 4 speed transmissions were used in General Motors cars from 1963 to early 1975. These gear boxes were used when power levels exceeded the limits of the early Borg Warner T10 4 speed. It was actually based on the T-10 design and uses the same basic gear layout. The T10 made it's appearance in GM cars in 1957. From 1957 to 1963 many changes took place inside the gearbox to meet the increasing horsepower the new engines were putting out. It was replaced by the Muncie in late 1963. The Muncie 4 speed was used in production vehicles until power levels dropped in 1975. 1975 was the first year catalytic converters , smog pumps, and low horsepower were introduced. These new requirements led to the demise of the Muncie and the reintroduction of the improved T10 called the Super T10.
While General Motors was switching gearboxes around from 1963 to 1975 other companies such as Ford and AMC kept the T10 in production. So we got to see T10, and First Design Super T10 transmissions end up in these cars. It was also an opportunity for Borg Warner to design replacement Super T10's for the Muncie. These 4 speeds offered 9310 nickel gears, had a wide variety of gear ratios, and were available from any auto parts store carrying the Borg Warner parts line. A variation of this Super T10 ended up in GM cars from 1975 to 1983. Also as the 4 speed section of the 4+3 Corvette Overdrive in 1984 to 1988 Corvettes.

http://www.yearone.com/updatedsinglepages/Id_info/muncie.asp
Don't have a 4 Speed........., but I have a 1960-1964 rebuilt 1/2 ton 3 speed transmission for sale @:
http://67-72chevytrucks.com/vboard/showthread.php?t=349416

[slorio]

The technical name for the 3 speed with overdrive transmission is T85 or T85N. They were two versions used in GM's. The first was with a non synchro first used from mid 50's through 1965 (four bolt side cover). The second was with a synchro first used from 1966 to early 70's. The second version is the one that I just installed in my 1966 GMC with 305E V6. Do they work? Yes, I am very happy with mine. They are basically a bolt in swap for the trucks with a factory 3 speed (except I used a floor shifter). Here are some links where you can read more about them:

http://www.classictruckshop.com/club...5n/rebuild.htm

http://www.classictruckshop.com/club...cts/how_to.htm

http://speedprint.com/deves50/overdriveindex.php

The transmission has a .7 to 1 final ratio. That means a 30% reduction in RPM's at highway speed. They shift "automatically" at 30 MPH into overdrive through the use of a governor switch and an electric solenoid. The trannies pop up on Craigslist and E Bay periodically. I bought mine from Craigslist. The only problem that I had was UPS smashed the governor in shipping and wouldn't honor the shipping insurance. If you have one shipped, you should have the seller remove the governor and the solenoid before shipping since these parts are hard to get and are damaged easily in shipping.

I hope the above is helpful.
regards,
Steve
New Orleans

[protrash64]

Thanx for the info Steve. The question I have is about the overdrive itself. Is it in the tailpiece similar to a Gearvendors? I understand the solenoid shifts in the final ratio.

[slorio]

Thanx for the info Steve. The question I have is about the overdrive itself. Is it in the tailpiece similar to a Gearvendors? I understand the solenoid shifts in the final ratio.


Yes, the overdrive is in the tailpiece. I am not familiar with the Gearvendors unit however.
Regards,
Steve

[slorio]

Seller doesn't know too much about it, but here is a overdrive 3 speed for sale in Texas. It is however, missing the solenoid. I don't see pictures of the other side to see if the governor is there or not. This is the post 1965 transmission with 7 bolt side cover and synchro first:

http://houston.craigslist.org/pts/1234985750.html

This is the same as the transmission that I used.
Regards,
steve
New Orleans

[55 Cameo]

There is one listed on Ebay: copy and paste this link to Ebay site for info http://cgi.ebay.com/ebaymotors/Warner-Overdrive-Transmission_W0QQcmdZViewItemQQ_trksidZp3286Q2ec0Q2em14QQhashZitem4cea2b0aa6QQitemZ330346203814QQptZ MotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessoriesQQsalenotsupported"]

[ol Curt]

That looks like a great deal. Maybe I could have been a bit more patient. I have purchased a TH350 with factory auto column and will be picking it up next Friday. I know it won't have the OD, but will make it much more drivable. After contacting several junk yards who had one advertised, only to find they wouldn't call back to answer any questions about condition or extra parts I gave up.

Thanks for watching for it. I'll pass it on to some others who have asked.