42 flat head 4spd ,fluids, how to drive

str8axle63

str8axle63

Member
I have a 42 ford / marmon herrington truck. It has a 8 cyl v8 and a 4spd .
I just got the truck running and driving, sort of. On my trial run I was grinding every gear, my daily driver is a standard so its not me. I am assuming the 42 does not have synchros? Do I have to try and double clutch and match revs? Also the transmission was pretty loud, would a trans this old take regular 4 spd fluid? The oil on the dipstick of the flathead seems pretty light, 10w 30? I was told the flatheads should be running a thicker weight like straight 30, is that true?
Does anyone know where I can find info on the old marmon herringtons? I have done searched the net but no really good info .
Thank you for your input
Donn
 
Of the handful of vehicles with non-synchronized gearboxes that I've driven, the Fords were far and away the easiest to shift cleanly. This includes a 1930 Model A, a '49-ish F-Series pickup as well as an older Dodge army truck. What I did with all of them is double-clutch every shift, basically: clutch in --> shift to neutral --> clutch out --> mentally count to two or three --> clutch in --> gently shift into the next gear. This worked flawlessly in both the Model A and F-Series, not so well in the old Dodge, which seemed to need about 10 seconds of waiting between gear-changes. Downshifting is a bit more challenging because you have to bring the revs up, but it's mostly the same: clutch in --> shift to neutral --> clutch out --> blip the throttle to bring the engine RPM up an appropriate amount --> clutch in --> gently shift into the desired lower gear.
 
Chuck's Truck in Conn are the experts on MH 4 wheel drive and also have a lot of truck stuff. on shifting gears, quit thinking about it and just do it, if you think too much on these you will grind the gears. engine oil 20W50 trans lube 140wt doping and 1 quart of Lucas oil extender, I think it helps with shifting. I have ground a lot of gears learning how to drive them, but it will come to you.
 

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You see the truck in your avatar?

Don't drive it like that.

you're welcome.

Mart.
 
Nope...no synchros. Double clutch if you are trying to (barely, anyway) keep up with traffic; if not, you can patiently wait for revs to drop and shift without it. As for the noise: some of it comes from the stronger, straight-cut gears whining as they mesh together; mine "sings" in the first three gears - although I normally start out in 2nd - 4th is quiet. Downshifting is more of a challenge, but kinda fun when you learn how.
 
alanwoodieman said:
Chuck's Truck in Conn are the experts on MH 4 wheel drive and also have a lot of truck stuff. on shifting gears, quit thinking about it and just do it, if you think too much on these you will grind the gears. engine oil 20W50 trans lube 140wt doping and 1 quart of Lucas oil extender, I think it helps with shifting. I have ground a lot of gears learning how to drive them, but it will come to you.
Click to expand...

I like your race car . I just started on my rebuild of an old 41 coupe that was Ed Browns , before that it was Mad Merion McDonalds ( name above the doors ) .It's set up for a sbc but I have a few flatheads or a Chevy stovebolt .
Nice rig .
 
A person needs to run it for a while to get used to the rpm levels when shifts are best accomplished. I always shift by ear for rpm levels. I double clutch, first to shift to neutral, then to shift into gear. I rev down to upshift & rev up to downshift. This gets the gears in there closest proximity to mesh before the shift attempt. After you get used to it, it will generally have no grinding of the gears unless there is a lot of wear & looseness in the mechanical parts.

An SAE-90 or multi-vis GL-4 gear lube is out there in the Stay-Lube brand name. A GL-1 will work OK but it doesn't have the gear protection that the GL-4 has.
 
Not a Ford, but I had a '48 Seagrave pumper with a non-synchro four speed. I can tell you from my experience with that truck that shifting one with no clashing/noises should become second nature after driving them for a while. My first attempt was a noisy disaster, but after a week or so, it became an unconscious action. I used to wonder why they didn't add syncro-mesh to the big truck transmissions, but after a little practice, there's no need for it.

+2 for the Sta-Lube GL-4. It's a lot cheaper on Amazon, but I got mine from the local NAPA anyway.
 
Nice to see another 42 Marmon Herrington on here :) Were are the pics and whats your trucks serial number?? Snogo has your original build sheet, if you call and ask they will email it to you. If your interested.
 
42Ford M-H said:
Nice to see another 42 Marmon Herrington on here :) Were are the pics and whats your trucks serial number?? Snogo has your original build sheet, if you call and ask they will email it to you. If your interested.
Click to expand...
Sent you a pm I would love to get a build sheet!! Im trying to figure things out now, what size rear gears and things like that. I had a lot of bugs to work out this past winter and just took my first ride on Saturday, maybe an 1/8 of a mile. She still needs a lot of attention
 
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