1939 transmission in Model A

Nosetime

Nosetime

Senior Member
Hey guys, long time no post. My project is slowly chugging along. I am doing the hydraulic brake conversion and came upon a new in box 1939 trans adapter kit and freshly rebuilt 39 transmission. The price is really good and am wondering , at this point to do this conversion. Anyone actually done this or have the set up? I will post on the Hamb, but appreciate all opinons. FYI...doing a mild banger roadster with end of the rainbow plan to put a V8 flathead in, so the trans would suit me down the road. I also do not know the status of my stock trans, so a fresh synchro trans with better gearing makes sense.
 
Nosetime said:
Hey guys, long time no post. My project is slowly chugging along. I am doing the hydraulic brake conversion and came upon a new in box 1939 trans adapter kit and freshly rebuilt 39 transmission. The price is really good and am wondering , at this point to do this conversion. Anyone actually done this or have the set up? I will post on the Hamb, but appreciate all opinons. FYI...doing a mild banger roadster with end of the rainbow plan to put a V8 flathead in, so the trans would suit me down the road. I also do not know the status of my stock trans, so a fresh synchro trans with better gearing makes sense.
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I've had this 'kit' in my '30 roadster for a dozen years now. Attached it to a B engine and '39 trans w/zg. V8 clutch setup and would only change if I were to go with an S10 5 speed. This '39 trans setup is the easy and best thing that you can do to a model a, IMO. You do not have to warm up an A/B engine either to do so. The 'kit' adaptors make it a smooth change that near anyone can do. Good luck :)

Where you located ? If in my area, I could/would give you a hand/pointers to make a quick job of it ? Add general info of location so that a guy would not have to ask each time,eh !
 
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I have a 39 box behind a flatty in my 28 A.

They are a great box.

I modified the 3 ends of the cluster and reverse shaft where they protrude thru the case so there are zero leaks.

I run synthetic GL4 oil and it shifts as smooth as can be.

Just remember, do not put GL5 in it.
 
Thanks guys, shoot Hardtimes, I thought I had added location. I'm in Huntington Beach and would love any info, Greg
 
Nosetime said:
Thanks guys, shoot Hardtimes, I thought I had added location. I'm in Huntington Beach and would love any info, Greg
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Ok, we'll talk tomorrow. I know residents of Huntington...seems like everyone I meet lives there ! Love your beach city weather :) BIG old car parades held there each summer, eh.
 
pooch said:
I have a 39 box behind a flatty in my 28 A.

They are a great box.

I modified the 3 ends of the cluster and reverse shaft where they protrude thru the case so there are zero leaks.

I run synthetic GL4 oil and it shifts as smooth as can be.

Just remember, do not put GL5 in it.
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Hey pooch:),
Great tip regarding the 3 shaft ends ! Many years ago, an OLD iron icon, Joe Mac and I rebuilt my '39 in his garage. There are differing ways to accomplish what you did. Here's my way....mill 1/8" depth into case...around each shaft end, and install 'soft plug' Never will leak again and you can remove plug for needed work if wanted !
 
Hardtimes, yep, that is exactly what I did, we call 'em welsh plugs over here.
Only I ground the ends down til I saw blue at the holes.


With the lousy pin and split /cotter pin idea at the back, I ground a little off the case to square it up, and put some booker bar/allthread in there with nuts and sealing washers each end.

The synthetic oil is like water, but never a drop underneath.

I got lucky as this is a box that came as is and did not look real pretty inside, but it shifts like a dream and does not jump out of gear.
 
Russ/40 said:
Hardtimes, did you use the Clings Kit?
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Hey Russ,
Yes, same idea, i.e.- alum adaptor(engine to '39 trans) and several (3) other adaptors...clutch, emergency brake and radius rod ball adaptor.

Well, to be honest in detail here, I made the three iron adaptors. I copied a friends parts. It was such a task that I wished that I'd have bought them. I will buy them if do same again.
 
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Hi Gents,
Please confirm the 39 is a syncro box and when was the syncro introduced?
Regards
Chris
 
The synchro box was introduced in 32.

The 39 box was the first of the modern seperate brass synchro and the last of the (car) floor shift.

This is why they are so sought after.
 
another way I fix the leaking shafts is to set the empty box up on the mill,clock up the shaft hole,bore it out 3mm dia oversize,then turn up a steel bush that is a press fit in the new bore ,but about .010 in undersize in its bore,then using a long bolt and some loctite.pull it into the new hole,then while still set up, bore the new bush to the original shaft size,Hey presto a shaft to bore fit as new.
I know not every one has access to a mill and lathe but the local machine shop could easy do this.
Lawrie
 
Two years ago I posted some photos of the conversion I did for a friend building a speedster. He ordered a rebuilt '39 transmission and a Dennis Cling adapter kit, both of which eased my job building the chassis. I had never performed this kind of transmission conversion, so this was new territory for me. The instructions were good, but some things still had to be done intuitively. If I can install this kit as a complete "hot rod" chassis-building newbie, ANYBODY can. I'm re-posting just those photos that may be relevant to your needs.
Marshall
 

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By the way, the shifter lever that came with the kit was steel sprayed black. I sanded it down to bare shiny metal with various grits of sandpaper (ending with 2500 grit) and then sprayed it with clear enamel. You can see from the photos how nicely it turned out, approximating the subdued original butler finish. I did the same with the emergency brake handle. One HECK of a lot cheaper than having these items re-plated!
Marshall
 
One more thing: the chassis is still exactly the way it appears in these photos from almost two years ago. The man building the body for this car has had some health issues, so the chassis is sitting as is in my friend's car museum until such time that the body is completed. If you need more transmission conversion-specific photos, I can take my camera to the museum and get the views you need. Pretty straight-forward conversion, though. The only tricky part as I recall was drilling holes for the wishbone ball mounting.
Marshall
 
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