m5 overdrive tranmission

[islandvu]

i need to know what trans. what top shifter and etc. i need to convert my 1946 m- 5 pick up any help i need and appreciate bob hogg pens. fla.

robert

[Roscomacaw]

Do you have the stock 3-spd in the truck now? Should be a T-96 tranny. Will say that on the side of the case.
You don't NEED a "top shifter" to convert to OD. You just need a T-96 tranny fitted with OD.[:I]

Miscreant at large.

[rockne10]

With a stock T96 you won't need to change any shift linkages. You will need the original 6-volt overdrive. There are a lot of them arround. The later 12-volt trans has a longer tail shaft with a splined output. You will also need the relay off the firewall, an easy to make wireharness, the OD lockout cable that runs to the dash and the kickdown switch from the accelerator bellcrank. Have I forgotten anything?

[Roscomacaw]

yeah - there WERE two years of 12 volt ODs that didn't have the splined tailshaft.
Further, in my pre-dawn drowsiness, I stated that it was a T-96 tranny for this application. Not so. It's a T-86. Still, if you could find a '51 thru '57 T-86 O/D tranny from a V8 car, that might be the way to go. Of course, you'd want the 6volt solenoid and relay to go along with the truck's electrics. The only impediment that I can visualize would maybe be a difference between the input shaft for a car vs. a truck. Probably the internal ratios are different too. Speculating here - I've never tried the swap myself.
Stude generally used the light duty T96 behind the 170 in cars. For truck applications, they used the T-86 behind the 170. Both trannys are top-loaders but the cover plate for the T-96 has four bolts holding it on while the T-86 uses 6 bolts.[^]

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[gordr]

While I haven't done an M5 myself, I'd concur with Mr. Biggs that you want a T86 overdrive tranny in there. The car transmission will fit, but you have to cut off a little of the input shaft, and trim off a bit of the splined area. Lathe with toolpost grinder, eh?

Truck trannies had straight-cut gears, and straight splines on the mainshaft, and a cluster gear to match. T86 car trannies are outwardly similar, but have helical gears, and a helical spline on the mainshaft. Because the cluster is different, you can't simply put a truck input shaft into a T86 car transmission. BTDT; it didn't fit.

IF... you can find an OD truck tranny, use it. Failing that, get a T86 car tranny, cut down the input shaft, using the input shaft of your present tranny as a pattern, and use that. You will have to shorten the front half of the driveshaft in either case.

The car trannies have a higher low gear and second gear, and for gentle driving, they work fine. If you are into pulling stumps, or hauling two prize boars up a steep hill, the truck tranny would be preferable.

Gord Richmond

Gord Richmond, within Weasel range of the Alberta Badlands

[Roscomacaw]

Thanks Gord,

I've got the M-series parts and shop manuals here and both show the T-86 with helical cut gears in them. Even the first-reverse sliding gear is helical whereas in the T-85 in my Transtar, that gear is straight cut.

I DO think your approach to adapting by modifying the input shaft is the most logical.

I also concur that for average driving, a car T-86O/D might be better geared.[^]

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS