39` trans in 30` Model A

farmerdick

farmerdick

Senior Member
Hey Guys, I want to put a 39` trans in a 30` Model A and need to know what kind of common problems to look for other than the obvious, concerning this era trans. I would rather not get into rebuilding one if I can help it. What should the teeth look like if their good? Should the bearings be changed reguardless? What would be a fair price to pay for a good trans? Has anyone done this type of swap? Any other tips would be helpful. Thank you.

Richard/Maine
 
Check for cracks in the front case between the countershaft and the input bore. Look at the condition of the 2nd/high synchro for condition. Check the condition of the low/reverse gear & countershaft interface for chewed up teeth. The cluster gear endplay can get too loose but it's hard to check when the unit is assembled.

If it has a lot of metal in the oil or if it's set too long with water in it, it will need an overhaul. I wouldn't trust folks too much when they describe the condition of these old light duty 3-speeds unless you can talk to the seller face to face with an internal inspection on site.
 
farmerdick said:
Hey Guys, I want to put a 39` trans in a 30` Model A and need to know what kind of common problems to look for other than the obvious, concerning this era trans. I would rather not get into rebuilding one if I can help it. What should the teeth look like if their good? Should the bearings be changed reguardless? What would be a fair price to pay for a good trans? Has anyone done this type of swap? Any other tips would be helpful. Thank you.

Richard/Maine
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Rebuilding is very easy. At least replace all the bearings. I wouldn't pay more than $200 for one with good gears and good shifter.
 
Make sure the shifter matches the transmission. If late 39up gears you will need the 91A 2/3 fork and they have become somewhat hard to find and/or expensive.
Many of these trans have seen a lot of use and abuse so it is important to have some kind of inspection from someone experienced with them if you are paying good money for it. Good info from rotorwrench.
 
Thanks again for the tips. I was allset with the adaptor kit situation but was mostly concerned with the condition of the transmission I will be looking at.

Richard
 
Maybe take a look at VanPelt's site for info. (He's a 'regular', here) Short of having his book, I'd at least talk to him on the phone. I'm betting he would be willing to talk you through a good inspection. And, of course, I'm sure he would be happy to sell you parts. JMO
 
rotorwrench said:
Check for cracks in the front case between the countershaft and the input bore. Look at the condition of the 2nd/high synchro for condition. Check the condition of the low/reverse gear & countershaft interface for chewed up teeth. The cluster gear endplay can get too loose but it's hard to check when the unit is assembled.

If it has a lot of metal in the oil or if it's set too long with water in it, it will need an overhaul. I wouldn't trust folks too much when they describe the condition of these old light duty 3-speeds unless you can talk to the seller face to face with an internal inspection on site.
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I have had good luck with a tire iron pushing the cluster back and forth to get some idea of wear while still assembled Much more than about 50 thousands is showing wear that will soon allow the bushing to spin and quickly damage the case. New bushings and shims can often save it.
 
When a person is checking countershaft cluster end play, .050" is probably too much. With normal wear & tear is shouldn't be more than .025" to .030" but some of these units have had hard lives. New part tolerance is .005" to .017". If that rear thrust pad casting gets all scored up then the case is about done. Some folks let this stuff go too far and it will ruin a case. Problems with 2nd gear staying in mesh can trace back to too much end play of the cluster gear.
 
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