Topic: '36 Axle tubes mated to '38 Diff Center...???


AZoldcarguy    -- 09-05-2012 @ 6:14 AM
  My '36 coupe has a 4.11 axle and I wish to go a bit taller on the ratio. And, I have a complete 3.78 axle from a '38, including torque tube, driveshaft, and arms. I'm wondering what my options are to get the 3.78 under the car:

1. Would the whole '38 rear assembly simply go under the '36 chassis... spring line up ok?

2. I would really like to keep the '36 arms and axle tubes. Will the '36 axle tubes mate to the '38 differential center, as regards bearings, etc.? Are '36 and '38 axles themselves interchangeable? I know I would need to use the '38 torque tube and driveshaft because of the 6 spline pinion and the forward lug for the arms appears to be in the same location on both '36 and '38 torque tubes.

Sure would be simpler if I could find a 10 spline 3.78 or 3.54 and just install that into my '36 rear and be done with it, but haven't found one yet.
Thanks!
Gary in Tucson


supereal    -- 09-05-2012 @ 11:25 AM
  Gary: I suggest you look into installing a Mitch*ll overdrive. They supply a new driveshaft and torque tube, while the rest stays stock. I have an OD in my '47 that gives a 33% reduction of my 3-78 rear. In traffic, I lock out the OD, and when I get on the highway, I can cruise with the traffic, and the engine revs equal those of about 45 mph when I am at or above 60 mph. I wouldn't go on long cruises without it.


JM    -- 09-05-2012 @ 6:21 PM
  3.78 gears with ten spline pinions should not be that difficult to find. 3.54 are more difficult but they are out there. Maybe a wanted ad here or on Fordbarn would turn one up for you. The six spline versions in those two ratios can be installed in your'36 rear by removing the 10 spline bung in your hollow drive shaft and welding a 6 spline bung in it's place. A good drive shaft shop could make that change for you.

JM


JM    -- 09-05-2012 @ 6:23 PM
  3.78 gears with ten spline pinions should not be that difficult to find. 3.54 are more difficult but they are out there. Maybe a wanted ad here or on Fordbarn would turn one up for you. The six spline versions in those two ratios can be installed in your'36 rear by removing the 10 spline bung in your hollow drive shaft and welding a 6 spline bung in it's place. A good drive shaft shop could make that change for you.

JM


JM    -- 09-05-2012 @ 6:24 PM
  3.78 gears with ten spline pinions should not be that difficult to find. 3.54 are more difficult but they are out there. Maybe a wanted ad here or on Fordbarn would turn one up for you. The six spline versions in those two ratios can be installed in your'36 rear by removing the 10 spline bung in your hollow drive shaft and welding a 6 spline bung in it's place. A good drive shaft shop could make that change for you.

JM


ford38v8    -- 09-05-2012 @ 7:24 PM
  Gary, Use your '36 torque tube, driveshaft, wishbones, and axle housings.
Use the '38 banjo and axles.
Use a 10 spline to 6 spline driveshaft/pinion adapter.

3.78 gears are considered the best ratio for all purpose use. Good off the line, in the mountains, and good highway speed.


Alan


42merc    -- 09-06-2012 @ 9:33 AM
  The 6 to 10 spline driveshaft adapter couplng only works with an external 6 spline driveshaft & a 10 spine pinion, not with an internal 10 spline driveshaft. The fix would be boring the 10 spline driveshaft to accept a 6 spline coupling & welding it in place. Not a big deal.
The easy fix is to use the complete '38rear end assembly. It bolts in.

This message was edited by 42merc on 9-6-12 @ 9:35 AM


supereal    -- 09-06-2012 @ 5:57 PM
  I agree with 42, except that welding a coupler must be done in a long bed lathe using a special technique to avoid warpage. We make and alter many kinds of driveshafts for cars and trucks. The slightest deviation from absolute straight will set up a speed sensitive vibration. It is a "big deal" to get it right.


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