Is it possible to fit electronic Over Drive onto different transmission?

[Privateer187]

This may not be the right place to ask this, and if so I'm sorry.

I'd like to know if it is possible to adapt on old-fashioned electric over-drive unit to a modern transmission? Specifically, I'm thinking of the Laycock units from Triumph cars, and a Ford T-5. The T-5 has similar stock ratios to the non-overdrive transmission in a Triumph spitfire, but with a built in final over-drive gear. I'd like to have the ability of having over-drive in lower gears (again, like the Triumphs).

Does anyone think it is possible?

[shovel]

I've seen add-on overdrive units for RWD vehicles, I believe one such unit ("the ranger" ?) fits between the clutch and main gearbox on New Venture transmissions. There are a few others which divorced-mount behind the transmission, or in some cases behind the transfer case on 4x4's whose owners need to remember which range they're in before engaging the front axle

No such unit would be useable on any type of FWD or AWD car.

[Privateer187]

Can you think of what those other "divorce-mount" units are, or where I might look for them? A unit intended for an NV will be too large to possible fit where I need it to.

[aerohead]

HOT ROD Magazine did an article late 2008/early 2009 on 8 or 9 overdrives.
Two of the units were mounted to the existing tranny's tailshaft.I don't have that info with me today but will try and remember for next time.
You may be able to search it at HR's website also.

[Privateer187]

I appreciate the point in the right direction, Aero. I checked out HotRod's website, and came up with bupkiss. If you can find the issue, let me know.

Gear Vendors makes Ford unit designed for a T10 that should fit the T5, but it is 3k! Little steep if you ask me.

[aerohead]

December 2008 HOT ROD had the article.
What I was interested in were the "auxiliary 2-speed transmissions".
Gear Vendors under/overdrive transmissions the most awarded auxiliary transmissions. and U.S. Gear Corporation Home Page are the two sources listed.
On HOT ROD's Ford Ranchero,and at 65-mph cruise,they picked up 2.5 mpg with the Gear Vendors unit behind a C4 trans.
The units allow gear splits between any gear.They ended up with a 6-speed.I would get a 10-speed if installed in the Toyota or 8-speed in the Dodge.
Price isn't mentioned anywhere in the article.If they are $3,000 that's really pricey as that would buy two complete transmissions for a Chrysler minivan.
The only way I could handle the expense would be to retain the original driveshaft and de-modify the truck at sale,transferring the OD unit into the replacement truck.
Nothing easy about saving energy!

[Christ]

Originally Posted by Privateer187

Can you think of what those other "divorce-mount" units are, or where I might look for them? A unit intended for an NV will be too large to possible fit where I need it to.

Unless it was intended for a 2.2L Chevy S10 with an NV3500 trans. Small bell housing there.

[Big Dave]

Its entirely possible. They are available off the shelf.

Its very expensive.

A Gear Vendor electric overdrive costs about $6,000 installed.

[Christ]

WHOA GUYS!!!

Install yourself a divorce mount xfer case backwards. You'll have some insane ratio, and you'll actually have to get a shorter geared transmission to use it effectively. It gives you two effective ratios, where low is high, and high is low. If you disassemble the Tcase, you can remove the second drive shaft garbage that you won't need, unless you plan on having PTO or something.

[Frank Lee]

Who has done that?

What I dislike about added-on ODs- besides the extreme cost- is the REDUCED driveline efficiency i.e. more shafts, more bearings, more seal drag, more oil splashing about, more joints, more weight, more everything that parasitically robs power. Sure they can offer gains that OFFSET some of that parasitic B.S., but why not simply re-gear what's there instead?