M37s and their trannys

[maddawg308]

ShieldWolf37 told me that his 1951 M37 has a double clutched transmission. He said that this was normal for manual shifting vehicles of the day.

My question is: did the later M37B1 have double clutched trannys, or did they have a single clutch?

 

[CGarbee]

Both the NP88950 (M37) and the NP420 (M37B1) are only synchronized in 3rd and 4th. You have to double clutch when going into the lower gears, but most folks usually start off in second when driving around so so shifting is pretty easy...

They only have one clutch...

Partially synchro'd and non-syncho transmissions used to be the norm, about the only transmisisons made these days that aren't synchroed are found in large trucks...

 

[zak]

First to second is non-synchro, second to third to fourth is synchronized on both series. The canadian model is fully synchronized. First is a creeper in both.

 

[maddawg308]

Re: RE: M37s and their trannys

They only have one clutch...

Well, I knew that! I just meant you had to push the clutch in twice to shift it. But your answer helped, I think what you're saying is from 1st to 2nd you have to push the clutch medal in twice to shift (once when shifting out of gear, once when putting into gear), but from 2nd to 3rd to 4th only requires 1 push of the clutch. Is this correct?

Forgive me, the M37s are WAY before my time, knowledge of the older stuff I'm a little green on.

 

[CGarbee]

Re: RE: M37s and their trannys

They only have one clutch...

Well, I knew that! I just meant you had to push the clutch in twice to shift it. But your answer helped, I think what you're saying is from 1st to 2nd you have to push the clutch medal in twice to shift (once when shifting out of gear, once when putting into gear), but from 2nd to 3rd to 4th only requires 1 push of the clutch. Is this correct?

Forgive me, the M37s are WAY before my time, knowledge of the older stuff I'm a little green on.

You've got it...

 

[Bill W]

RE: Re: RE: M37s and their trannys

"First is a creeper in both."
Yes and both 1st and reverse are spur gear ( on both models )
All "M-series" vehicles were required to have syncro'd trannies
I believe a lot of the misinformation regarding the early and later M-37 trannies is that they have the same bolt up pattern as the early crashbox trannies that were in the WDX power wagons and 3/4ton WC's. The B1 tranny is a NP420, for the sake of interchanging with the earlier M-37 they kept the boltup pattern the same

 

[nattieleather]

RE: Re: RE: M37s and their trannys

The whole purpose for double clutching was to slow the RPMs of the motor down so you could slip into the next gear. You could get the same effect by just taking longer to shift....

Hey Bill W nice light weight in your avitar!

 

[SasquatchSanta]

RE: Re: RE: M37s and their trannys

I think you'll find it's to slow the speed of the transmission in-put shaft.

 

[Capt.Marion]

RE: Re: RE: M37s and their trannys

The transmission is essentially a 3 speed, with a 1st thats too low for on-road use, but perfect for heavy pulling. Similar to the M151 Transmission in theory. One will also find that on most M37s, 2nd is a PITA to shift through, whether going up or down (from 1st or 3rd...) even if you are double clutching.