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Unusual Auxiliary Transmission … Can Anyone Identify It?

• CATEGORIES: Features, OD Other, OD Borg Warner/Rancho, OD Saturn/Warn This site contains affiliate links for which I may be compensated.

UPDATE: While still unidentified, we have learned thanks to the Dutch_Jeeper on the CJ-3A page that the auxiliary transmission is an “under-drive” rather than an overdrive. He pulled this out of his CJ-3A, then disassembled it.

You can learn more and see more pics here:





Originally Posted February 5, 2021: An owner of a CJ-2A posted onto Facebook these photos of an unusual auxiliary transmission. I only am aware of two that work between the T-90 and Dana 18 (the Warn and the Husky). Anyone recognize this?

IMG_1879 IMG_1880


13 Comments on “Unusual Auxiliary Transmission … Can Anyone Identify It?

  1. Brian

    Cool little gearbox!

    The pics made me think of an article about early jeep drivetrain variants. Curiosity compelled me to root through my files of clipped out articles and I found the reference I was remembering. The description doesn’t fit these pics that well, but since several variants were built, it might be a clue.Thought I’d pass on the info none the less:

    The article is “Old School” by Willie Worthy in JP magazine, Nov 2006. Here’s the part that was interesting:
    “Believe it or not , there actually was a three speed version of the Spicer 18 built back in the 1960s. Thing is , it wasn’t built by Spicer. It was made from plate steel that was welded together and then heat treated to relieve the stress before being machined. It had to be about 1962 or 1963, and I was for some reason or another in Buschert’s Machine Shop in Hemet, California. Harry Buschert was showing a buddy and I this prototype he had developed. I don’t think there were over a half dozen ever made, and each one was a bit different. I wouldn’t swear to it, but I believe it had a lower low range than the normal 2.46 gearing, and a high 1;1 high range, and an overdrive range. Harry was on the right track and way ahead of his time when he built these. Little could he imagine that someday a three speed and four speed transfer case would be in production.”

    The article stuck with me because I thought such a variant on a Spicer 18 sounded great! Maybe you have one?!

  2. David Eilers Post author

    Thanks Brian. Cool info. I saw a similar article in Four Wheel that directed me to the Sierra TC, but didn’t know about the Buschert project. I”ll see if I can hunt down that magazine on eBay.

  3. David Eilers Post author

    Awesome. Thanks for the link. I need to study those pics more carefully.

    – Dave

  4. neal jung

    the best jeep dana model 18 t-case overdrive was the old RANCHO unit , it bolted on the rear of the t-case where the rear driveshaft attaches — the RANCHO unit let the noisy , whiny mod 18 t-case slow down at highway cruising speed — the warn od speeds up the t-case , same problem with this oddball unit here — of course the RANCHO OD was only useable in 2wd and you would blow it up if it was in OD and you put the transmission in reverse – i have a rare RANCHO mod 20 overdrive also ,,

  5. John North Willys

    David — All Rancho overdrives were based on the Borg Warner R-10 b electric overdrive — same overdrive as all Willys 2wd vehicles had , and a lot of other car makers , ford , gm , studebaker , rambler , etc — Rancho just made the adapter to use any R-10b overdrive — or they would sell one complete in a kit .. they used to advertize all the time in old Four Wheeler magazines — 1970’s ??

  6. David Eilers Post author

    Vernon, I knew about the Rancho’s on the back of the 18s (and on the back of the 2WDs), but I didn’t know about the Rancho on the back of a Dana 20. So, Rancho made a Dana 20 adapter so the Rancho (or BW) OD could be used on the back of that?

  7. John North Willys

    hello — yes , rancho made an adapter so you could bolt a B/W R10B overdrive to the back of a dana model 20 transfer case — i have one , its like the holy grail — of course you had to shorten the driveshaft and hook up the wiring – solenoid , governor , rail switch , relay , kickdown switch etc – also hook up the overdrive control cable to the dash — i’m saving it for a newer 67–> up jeepster commando build up — search for an old rancho ad and you will see it — how about the bruce springsteen commercial for jeep during the super bowl ? — that jeep wasnt even that old ? 1970’s ? AMC ? — bruce sells out , something neil young still refuses to do — though selling out for jeep is really not that bad ?? – i didnt recognize him — had to look online to make sure that was bruce ?

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