39 rebuilt ****** noisy and hard shifting 2nd 3rd

M

Mike/NY

Member
I have a 1939 Ford Deluxe Sedan with a 39 Merc ******. The ****** worked ok and was quiet but the syncro on 2nd and 3rd was not working at all. Being a 39 Merc ******, it is with the blocker syncro. So I bought a NOS 1939 Ford synconizer some years ago, also a NOS main shaft and 2nd gear to put in.

We took the transmission out by removing the rear axle, big job. We put in the new NOS syncro parts, also put in the NOS main shaft and 2nd gear along with a new bearings and shims. Old gears were in fact all in excellent shape and swapping them might have been a mistake and causing noise now? Everything works ok but:

- syncro works as it should but shifting is hard to 2nd and 3rd requiring some force, 1st and reverse slides in with ease. The new syncro has pretty stiff springs, maybe the cause? Shifter top works properly and everything is correctly put together according to my pretty experienced old time Ford mechanic but who knows (he has rebuilt numerous 37-49 trannies, one of which is in my 39 Conv and works fine but has earlier syncro),

- the ****** is noisy on 1st and 2nd, not so much on 3rd, there is a variety of noises, and when I come into a traffic light and shift to neutral you can still hear the something turning for awhile before the movement stops. Also when you push in the gear shift to shift to 2nd and 3rd you hear a hiss, I guess from when the synconizer pushes in,

Before rebuilding the ****** the ****** was pretty quiet. Maybe mismatched gears cause noise,

- I am using 80W90 lube now but have 90W140 waiting, maybe this will help to quiet it down. Maybe driving will break in the new gears? It now has just about 300 miles on the rebuilt ******.

Any ideas, the real issue here is pulling the ******.
 
There has been problems with the blocker rings. Did you replace bearings? What style syncro did you install? Did the transmission get checked for end play tolerance before re assembly in the car? Suggest you remove the top and see what is going on to get a better idea. Was the new syncro disassembled and inspected before install?
 
All bearings were replaced, used new complete rebuild kit from Early Ford V8 Sales (formerly in upstate NY), I used NOS blocker syncro rings (same style as was in ****** originally), not repro and it was disassembled and checked ok. Springs seemed alot stiffer than the ones in the car.

I need to ask about the end play from the mechanic. After test drive he did remove the top and to check everything and claimed everything was correctly put together.

One thing, slowly shifting to 2nd and 3rd has become a bit easier, noises have not gone away .
 
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You need to get a copy of Mac VanPelt's transmission book. From the symptoms it sounds like you have several problems in there. You can check the cone faces of the blocker rings while they are out of the box and that will tell you if they are OK. As far as I know, there is no difference between the 39 Ford and Mercury transmissions. Both used the flat plates with C-springs instead of the coil springs & ball bearings in the synchro hub. The later ones used the coil springs & balls then somewhere in the late 40s they went back to C-springs. You also have to watch out what 2nd gear you use with which main output shaft. Some use the spring & pin lock and some don't. All this stuff is in Mac's book. I can't over state how important it is to have that kind of reference.
 
Mike,
Something overlooked by whoever is making syncro rings is the dimension
from the back side of the ring to the bottom of the 3 slots. This dimension should
be .301 / .304. If this dimension is oversize enough there will be no or insufficient
clearance between the ring/s and the 'cones' on 3rd gear and second gear and the
rings will drag . What happens now is the rings attempt to drive 2nd and 3rd even
when the trans is in 1st or rev.
Charlie ny
 
i have bought some rings that the slots were not deep enough and had to machine them to spec.i think charlie ny is correct
 
New bearings have been problematic due to where they were made. If you used NOS Ford bearings there shouldn't be any issues but the fact that it was quiet before rebuilding makes me suspicious of the bearings. Even some of the MVP bearings had the soft cages. I can't imagine it will get quieter, might have to take it all apart again.
 
Re gear oil .... I'd stay with 80w-90 at least until you solve your shifting problems. I changed to Stay-Lub GL-4 90w and use it all the time here in upstate NY and my ****** shifts much smoother than before.

The 90w-140 might dampen your gear noise but depending on your seasonal climate, the thicker viscosity 90w-140 is likely to cause stiffer shifting.
 
if you put new gears against old gears there will be some noise--but in high the noise should noticeably change as you are no longer "loading" the gears
 
The bearings are new but whatever came in the kit, some maybe Nos, some foreign. I have the same kit in my 39 Conv with no issues.

The main shaft and 2nd nos gears should be matching, they came from same source. Blocker is NOS and exactly like the one in the 39 Merc ******, all parts were identical. The new springs in the synco were much stiffer than old ones?

Yes, it quiets down on 3rd so cruising is pretty ok. On 2nd it is pretty noisy, almost like 1st, but 2nd gear is new.

From your answers dragging/clearance might be an issue. Can this be checked with shifter cover removed? Obviously it cannot be fixed without removing ******? What is the best way to remove the ******?
 
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if you can drain the trans fluid, flush out the box and put Prussian blue or a grease on the gears and slowly turn them you might be able to find the gear pattern or contact area. I have a 4 spd that had a bad output bearing and when that was changed the gear pattern changed so now I have a noise except in high gear
 
Another thing to check is the pilot bearing for the tip of the main input shaft. If it is a bushing and has excessive wear, it allows the main input to deflect off center and that can make for a bad gear mesh with the counter shaft cluster and put the connection to the main output in a bind.
 
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