what is this

[robert1839]

Does anyone know what this is out of exactly? I got it from a guy it came with the Buick 215 I got and he was going to charge me the same amount if I took the trans or if I left it so I took it in hopes I can sell it or if its not worth anything I can just scrap it, he side he got the it out of a jag but I have no idea what year or what jag

[Moderator]

My guess would be Borg Warner type 35. Further info here: http://en.wikipedia.org/wiki/Borg-Warner_35_transmission

[BlownMGB-V8]

Looks like it probably is. Removable bellhousing, right? Oddly enough those are in some demand by people who need to drive an automatic for medical reasons. I'd guess you could get a couple hundred out of it without any problem, even if it needs freshening up. Easy to tear down and repair, it's one of the simpler automatics and is not loaded with "gotcha"s like some of the newer ones. I had an iron case BW35 in my I-H truck, rebuilt it and it worked just fine. No lock-up and 3 speeds, it tends to transform the stock MGB into a slug but if you can't work a clutch it is the simplest route and with the BOPR engine, power is quite adequate.

Jim

[robert1839]

thanks how could I tell if it is still good

[eyeosteverino]

Hey, better late than never...

I believe this is a Oldsmobile Hydra-Matic, a four speed automatic.  It was  a smaller version than the standard trans used  in the FSCs and  was mated to the 215.  I think it was called the "Jetaway"  FWIW, the Buick engine would have had a two speed  Dynaflow.

[joe_padavano]

Yeah, two years late...

In any case, that trans is a RotoHydramatic 5, used only in the 1961-63 F-85/Cutlass line behind the 215.  It does not use a conventional torque converter but instead has a fluid coupling in the middle of the trans.  It does not use a conventional flexplate on the engine but instead has a fairly heavy flywheel with a bolt-on hub that looks like the center of a manual trans clutch disk with the springs and splined hub.  The trans has an input shaft that looks like the one on a manual trans.  While Olds called it a "4-S" transmission, it has only three gear sets.  The "fourth" gear is actually obtained through the fluid coupling, similar to the "switch pitch" torque converters used by Olds and Buick in the mid-1960s.

[roverman]

Substantial as a door-stop, barely.  2 seconds slower in the 1/4 mile, than the optional 4 speed stick. Had one in my 61 Cutlass, replaced with a Vega turbo 350 and it felt like I added 50 hp, under the hood. Among the worst-ever, of early slip n slush boxes.

[eyeosteverino]

It is interesting how each division of GM went their own way to develop the automatic transmission.  No shift Dynaflows, two speeds, three speeds, four speeds, Duel Path, SwitchPitch, and more, but all  ending up with the excellent THs. .  I wonder why, with the  high power of todays engines, eight speeds are necessary.

[joe_padavano]

"I wonder why, with the high power of todays engines, eight speeds are necessary."

Simple. Fuel economy.  Internal combustion engines can be very efficient when optimized for a narrow RPM range.  More gears allow the engine to stay in this optimum RPM range for a greater period of time, thus improving economy. CVTs are optimum for economy but difficult to implement, especially for higher HP motors and heavier vehicles. Eight-speed and nine-speed transmissions approximate CVTs.

Also, while today's engines may have high HP ratings, the DON'T have the high torque at low RPM that older V8s did have.  Many gears are needed for smooth operation over a wide range of speeds and accelerations.  Witness the gearboxes in 18-wheelers, for example.

[roverman]

Modern automatics also have higher efficiency than the old 2 and 3 speeds. Less internal friction, optimized shift points, cleaner shifts,( friction surface longevity). With less ratio spred between gears, less torque shock to the trans and drive train.  This is a case of more is better.

[BlownMGB-V8]

Plus it gives you some ballast down low to keep the car from tipping over and pulls the polar moment of inertia closer to the center of the car for quicker turn it! Win/Win!!  ;-)

Jim