'52 M38A1 Questions

Hello, I have a few questions to ask of this forum.

1) I'm looking for a rear seat frame. Is the frame model specific or will other model frames work?
2) Obviously the driver's seat isn't adjustable. But I'm a little taller than what the fixed seat allows. Does anyone know of an adjustable kit or has anyone improvised this problem themselves due to the placement of the fuel tank?
3) Has anyone ever changed the rear differential gear ratio that would allow some highway driving? If so, what gear ratio did you use? I'm more interested in keeping up with the traffic flow and not be run over!

Thank you!

Doug, I don't have any knowledge about the seats, but if you change the rear ratio, what would you do about the front?

I can help you with number 3 Doug.

The model 25 you have up front is getting a bit rare. The problem is you need to match your front and rear ratio.The Model 44 rear has a plethora of ratios available. The front 25 does not. The 25 was available in 4.27:1, 4.88:1, 5.38:1, and 6.17 ratios. The best you could do is the 4.27. I don't think you will find that ratio. The 4.88's are out there. That is probably what you have.

The overdrive (and tall tires) is the way to go for what you are trying to accomplish. A little attention to the drive shaft angles and it will work for you.

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Originally Posted by okiemark

Doug, I don't have any knowledge about the seats, but if you change the rear ratio, what would you do about the front?

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I’m new to this gear ratio stuff, but assumed if I only changed the rear gear ratio and utilized 2-wheel drive, I could keep the low end gear ratio in the front to use on a “as needed basis”

Doug, unfortunately that won't work if you are running the same size tires on the front as you are on the back.
They both have to be the same gear ratios or it will bind up when the front axle is engaged, they need to be synchronized together as far as wheel rotation goes.
There are formulas that you can use to run 2 different gear ratios but you need to change the tire diameter size (on the front tire diameter and rear tire diameter) to compensate for the different gear ratios, but as Bmorgil said earlier with the 25 front axle doesn't have many choices of different ratios so your odds of changing the tire size are slim to none.
Your best bet would be either changing both gear set's to match or like Bmorgil said a overdrive unit to bolt on the back of the transfer case.

If you only were to use 2 wheel drive, you could do that, but I would remove the front drive shaft to keep from damaging the transfer case if accidental engagement.
As TJones and Bmorgil said, I would as well go for the overdrive. Then you would be 4 wheel capable, and have a bit better performance.