Crazy T-case Idea

Well, this doesn't really concern an ECJ5, just an ECJ5 T-case... Most of you know I've recently acquired a '49 Chevy 3/4 ton pickup project. In the course of the next year, I'm planning on building into my new daily driver. The one problem as that these things are geared wayyyyyyy low (either 4.57 or 5.14) and higher gears are not available at all. Nobody ever made any for them. Anyway, I want to retain the original engine and tranny. I'm thinking of a way to somehow divorce mount a D18 and stick an OD in it to make the thing more driveable. To my knowledge, nobody makes an adapter to bolt a D18 to the '49 Chevy sideloader tranny. So now the hardest part is going to be to devise a way to hold the input gear...I could probably use an old output shaft out of a T-90 or whatever and have the other end of it resplined to accept a U joint yoke. I just don't know what kind of adapter to make or how to hold it with bearings. I'm not really concerned about having the offset output. The rear driveshaft is so darn long that the angles would be pretty minimal and besides as long as the t-case output is aligned with respect to the pinion (even though on different planes) I won't have any vibration problems. The driveshaft in an ECJ5 actually isn't pefectly inline with the vehicle either. Any thoughts? Am I just plain crazy?

 

Is the '49 2wd? If it is there are lots of divorced OD boxes out there that would be much easier and less money if you are just after an OD.

JB

 

yeah, it is 2wd...I haven't actually found anything that's a direct bolt in though...

 

http://www.gearvendors.com/faq.html

 

1) www.gearvendors.com should have what you are looking for.

2) thought about axle swap?

 

$2400-$3500 for Gearvendors...I think not. It would never pay for itself in fuel savings. I have thought about an axle swap, but I'm trying to keep this thing somewhat original. You should see the size of the rear axle in this thing...it makes a Dana 60 look tiny. It's a full floater and the axleshafts themselves are probably 1 1/2" to 1 3/4" in diameter. This thing is going to get USED like a truck should so I want it as beefy as possible...especially since I've broken springs in my F-250 in the past. So basically, I have to find a way to make my own gearvendors unit.....time to fire up Autocad

 

tranny swap?

 

I thought about that too, but I've been through all that before (with my Jeep) and I really don't want to do it again. This is a torque tube type drivetrain so it really isn't easy to just swap out the tranny. I really do want something that's just stock and somewhat correct, since it is an antique. I'm just kinda throwing ideas out there for now...

 

Read an article about this some time back. The guy put a T5 in it. I'll see if I can find it. Seems to be a pretty easy swap. if there are any.

 

The B/W OD used on the 2WD Willys wagon was also used by GM & Ford in that era. Try Hemmings or Ebay.

 

Use a Brownie box

 

Advance Adapters sells what they call a 'torque splitter' unit that bolts to the front of the transmission.

It is availavle in underdrive or overdrive (but not both in the same unit) format.

It isn't cheap, but I bet that if you add up the cost and reliability measures on what you are trying to do vs the torque splitter you'll find that the cost differential is pretty small.

Reliability goes way way up because they have been selling these things for years

 

I think your best option is to replace the axle. As I recall, the early GM trucks have a closed axle (the drive tube is attached rigidly at the axle, and there are two struts from axle to the drive tube). These are commonly replaced - there's a site (have to search) that lists appropriate replacement axles, with the right width and bolt pattern to match the stock wheels.

 

From more reading, looks like the torque tube ended in '47. You must have an open driveline.

From this site http://www.chevytrucks.org/tech/ifs&rearend.htm it seems that you can use a rearend from a later Chevy truck. The newer trucks with V8s should have lower (numerically) ratios. You may be able to buy just the gears at http://www.rearman.com/truck.htm

 

http://www.inliners.org/Jack/Robt_french.htm
http://www.stovebolt.com/techtips/t5tranny.htm
couple of articles for overdrive trans for these trucks

 

I've got a 54 chevy 3100 with a torque tube.........'47 must not have been the end.

JB