The Stovebolt Site Forums The Shop Area Engine Shop 1954 3800 series hard shifting when it's cold

Now that I have all these little things fixed on my 54 ton truck. I have been driving it more, actually a lot more. I have put more miles on the 54, than I have on my newer Silverado, almost three times as many this past couple of weeks.

BUT, I have NOT been able to drive it in the mornings to work becasue now that it has gotton cooler out, I can't get the thing to shift into gear. I'm scared to try to frorce it into gear for the fear of breaking a shifting fork or somthing else. I come home at noon for lunch and by that time the temp gets up in the high 40's or higher and take it back to work with no troubles. I think to myself, what's going to happen when it really gets cold out and stays cold. Yes, I plan on driving it all winter too. My 2000 Chevy "sucks" for traction in snow and I despise them darn ABS brakes.

I'm thinking of changing the transmission oil. It smells like sulfur, like my 8N did when I changed it a couple yars ago and more than likely it is the original oil that came in it when it was new in 54.

NOW, shouldn't it have something like 80 or 90 weight gear lube in it??? PLEASE! correct me if I am wrong here. I don't have any manuals what-so-ever on maintence on this old truck. All my information I get if from the Stovebolt site here.

What about the transmission itself, should I drain the old oil out and use something in the transmission to clean it out? My Model A and 8N **** manuals suggest using kerosene, let it run at idle for a few minutes to bring it up to temp, then drain it out and install the correct oil or fluid. I don't have any kerosene, but I do have 5 new gallons of parts cleaning solvent for my solvent tank.

If so what would be the procedure? Drain out the old crap drive it around the block a couple of times or just let it idle in neutral for a few minutes?

I "think" the transmission is a SM420, (4 on the floor) it has dual independant PTO outputs, I assume they both are lubed via the transmission oil too and what I could find on this transmission it takes 6 1/2 pints of oil, might need to add another pint for the extra cavities for the PTO housings.

I would guess you would fill up the transmission to where the oil runs out of the fill/check plug on the side of the transmission.

One thing I have to say, that old 235 6 banger fires right off on these cold mornings, just can't go anywhere after it starts, LOL!

Thanks for any help or suggestions.

John N.

Sounds like the oil could definitely use a change. I'm no pro, but I've always used 90 weight in my sm420 and I've had no problems. With you being in the colder climates I would be curious to know if you could find a lighter oil for better shifting.
I haven't heard of methods for cleaning out the gearcase, though I would warm the tranny up before draining. I always filled my tranny up to the fill hole. Not to say that's the right way, just what I've done.
Best of luck,
Bo :o

Seems to me that other 'bolters have complained of water getting into their transmissions. I never found out how it was getting in there, but I believe it was only occurring with the SM420 gearbox. :confused: Hopefully, someone has solved this problem, and can provide some answers.

If water is freezing inside the trans, it may explain the morning lockup. Drain it.

John

You're experiencing the way they were. We used 90 weight and they were hard to get into gear when it was cold, but after a few miles, it got better.

If it was me, I'd invest in a synthetic lube that stays less viscous when cold. Should solve your problem. GM recommended that we do this in the 80's and 90's and it seemed to work.

I'd drain the oil and not waste too much time cleaning, unless it's really dirty. The odor seems normal. Fill the transmission up to the bottom of the fill hole.

If you decide to flush out the transmission, you might let it idle for a while, but I sure wouldn't drive it at all without porper lube in it.

Well, here's the scoop.

I went ahead and changed the transmission lube today after I drove it about 15 miles to get the transmission as warm as possible. I took it in the shop and let it drain while it was still warm. That stuff was like tar and just as black.

While it was draining or should I say oozing out, I change the oil and filter thermostat and some other regular maintenance things that I have been putting off. When all was drained out, I left it sit in the drain and decided to see what it was like cold. I took a broken broom handle and tried to stir the crud and the stick stood straight up. I could not hardly stir the oil (or whatever it was) AH! no wonder I couldn't get it into gear.

On cleaning out the case with anything, I just decided NOT to. I went ahead and put in the new gear lube. I used a Mystic gear lube 80/90 weight. I will run it until next Spring and change it again. Speaking of that, any good ideas on re-filling? I had one hell of a mess with lube everywhere! I tried using a small hand pump, that was worthless. Then tried using a funnel with a hose through the battery box compartment, another stupid plan. MORE MESS!

Well anyhow, Hedgehog posted where others have said where water has entered their transmissions and it could have been freezing. Like him, I thought well I didn't know how water could get into the transmission, but heck anything is possible. On my 8N that was the case, but I'm sure it entered through the rubber gear shift lever boot. I guess maybe on my truck it could have been condensation over all the years. I think my problem here, was just really, really nasty thick gear lube.

I left it sit for several hours in the cold and so far, so good. It shifted real smooth with no trouble going in or out of any gears. Tomorrow morning will be the real test. Holding my breath and going to knock on some wood

Thanks for the advice guys.

John

I fill mine by pulling the floor cover and putting it in from the top, either with a hand pump or funnel with hose.

As far as the water goes, you are likely getting it in the top gasket. I noticed that quite a bit of water runs down the bellhousing if the cab to hood seal is missing or if the cowl vent seal is bad.