Packard Forum Index » Pre-War (1899-1942)

Keith,

The major differences lie in the engines and bellhousings, "junior" Phil's '38 v "senior" cars Tom's '34. Phil's trans/OD unit bolts to the bellhousing but still needs other 'minor' mods to get it to work.

I'm confused. What does the bellhousing (ANY bellhousing )have to do with the overdrive unit??? The OD unit bolts to the back of the trans, NOT the front of the trans. No???

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Hi again Packard V8!

Good question. Of course you are correct that the Borg-Warner type overdrives bolt to the rear of the later transmission - that is, if you ordered overdrive as an "option" on 1939 (or was it 1940) and later production.

Well..it isn't quite that simple - to install a Borg-Warner type overdrive, you have to start out with a transmission whose rear case is designed to accept it.

So those of you with "Junior" pre-war Packards that were not factory-equipped with overdrive, have to hunt down and come up with an entire transmission already so equipped. Again, you cant simply bolt on the Borg-Warner type overdrive to a non-overdrive transmission.

So that rules out adding a Borg Warner type overdrive to Packard transmissions of ANY series, "Junior" or "Senior"

So, given the above - it really dosnt matter that there is still another reason why a "Borg-Warner" type transmission isn't going into a pre-war "Senior". (this is in addition to what I noted earlier - the pre-war Senior engines, with their transmissions removed, had no bell-housing on which to bolt a modern-style transmission. Again, the bell housing was cast as part of those huge "Senior" transmissions).

There is the little matter of the truly massive frames of the pre-war large Packards - a huge cross-member DIRECTLY behind the transmission ! No room!

Bottom line - for those of us with big pre-war Packards who want to lessen the wear-and-tear of very low axle ratios. Either "re-gear" them with a much "higher" rear axle ratio (which is only practical on the biggest-engine "Senior" Packards of that era with their incredible torque) or go to a overdrive that can be attached to the frame-rails in between that huge cross-member and the "banjo" of the rear axle.

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FWIW, I've got an older hot rod B&J overdrive unit designed to go behind a GM TH400 or TH350 which could be adapted to a stand-alone unit. Any informed opinions as to how long an overdrive could be fit between the crossmember and the rear axle?

jack vines