The Stovebolt Site Forums The Parking Lot Big Bolts What 5-speed is this?

What do you think? 69Cuda pointed out that my PTO was on the wrong side. I just assumed my truck would have a SM420, but it clearly doesn't. I haven't gone back out to look at it, but from this terrible pic I have online already, I'm leaning toward NP540. What do you all think?

Obfuscated transmission pic

The easiest way to identify 5 speeds is by their shift pattern. The New Process has 4 positions toward the dash and only 2 toward the seat.

http://www.chevyc60.com/the_transmission_page.htm

Thanks for the link, that will come in handy. That's not the shift pattern i expected. Unfortunately, I can't get it to shift through all the gears where it sits. It'll probably be easier with the engine running.

I did add another pic to the link above.

They are good trans' , I put one in my early Bronco to get a closer ratio trans, with the stock 3 or 4 speeds, with a load, there was too big a gap to be able to shift into top gear. It is esentially a 435 with another synchro gear. Adapted to Dana 20 t'case with 435 castings.

Ed

The New Process can easily be identified by its unique shift cover.

https://picasaweb.google.com/108197707187186692269/DropBox#6270215574163753186

I drove a NP541 in a 550 GMC about a half a million miles. The close ratio between 4th and 5th which we called a "working 5th" gave me a big advantage over other trucks of the day. I notice in your photo album you have a ratio chart. If you notice the shift sequence is from 4th low, 5th low, back to 4th high and then 5th high. The close ratios of the last 4 gears allowed me to show tail lights to 409 Chevs with a 370 cu. in. GMC in rolling country. Also 671 Detroits and 250 Cummins with a 10 speed were no match for me because the big gap between 9th and 10th killed them. The goofy arrangement of 1st and 2nd and then the working 5th took some getting used to. But in those days we drove 18 to 20 hours a day and that gave me plenty of practice.

That trans is also relatively easy to downshift from second to first, double clutching of course.

Ed

I found 1st and 2nd rather awkward. In fact we had 2 1st gear hills around here and I would almost stop before I approached the hill because I knew I couldn't go from 2nd to 1st fast enough.

However, the real advantage of the transmission is demonstrated in the chart pvfjr posted.

https://photos.google.com/share/AF1...RXBXV2NDMFVFUlltTkVFaGVaM0VBMWxONC1ucU1n

It shows 62.2 as top speed with the low option axle and 69.1 as top speed at 3000 RPM with a 6 cylinder. My GMC 550 had a 370 which was actually a 371 Olds. I shifted up at 4200 and shifted down at 3800. I ran 10.00x20 tires that did about 500 revs per mile. Put the speed calculator to that. And then I hear all these stories that these trucks were meant to go 45 MPH.

Unfortunately, I made that chart when I was pipe-dreaming about finding a NP540-GO when I was assuming that I had an SM420. Odds are good that if I already have a NP540, it'll be the -GL version with a 1:1 fifth in it. But, it'll have a much better gear spread, so I'll take what I can get.

Easier than an SM-465? That's my status-quo for comparison; spent quite a bit of time driving those. I basically resigned myself to only putting it in first from a dead stop. Of course, I rarely needed 1st, since I had a 454, 4.10's, and 33's.

My NP541 with a working 5th was in a 550 GMC with a Neway drag axle that grossed 80,000+. I only used 1st when I was loaded. Empty I weighed about 20,000 with an aluminum and I always started in 2nd gear and only shifted the 2 speed in 4th and 5th. Of course, when I was loaded, I had to use every gear I had. I only used the clutch to untrack.

I have several 550 GMC. The only one I have with a NP541 with a working 5th is a wrecker.

https://picasaweb.google.com/112636930370126476644/DropBox02#6270596488369924722

I don't remember if better or worse than 465, drove both, I suspect whatever one is used to might have seemed best.

Ed

I think it's a Clark...maybe
I managed to get it to shift through the gears today while sitting still. It's 3 positions to the front, 3 to the rear. The two right-most are against a spring, much like a typical 5-speed. Those could be 1st and reverse on the right, I feel like I've seen that before.

So where do I look for casting numbers? This thing is quite dirty, and much of it is not easily visible. A targeted search might make it easier.

5 speed pics


Here are some more pics. What is this thing?

Looks like Ci top cover, not 540 series, however, predecessor to 540 series is all Ci, seen only in Chrysler configuration, non-synchro.

Ed

What is a Ci series? Who makes that? I'm not finding it in any searches.

So is it not a clark then? The shift pattern is like this:

|_|_|
| | |

Ci equals cast iron, shift rails extend in front of trans mounting surface, not sure if shift pattern is same as 540 series, never drove one, however I suspect not. Modern Clarks have Al shift covers, not sure about older ones.

What engine is it behind?

Ed

That's a great question. My engine doesn't have a serial number, so it's probably a replacement. I just found the casting number page, so I'll have to look for those so I can see if it's a 235 or 261.

So are you saying that it could be a Clark, but just an older aluminum free variety? Maybe like a 207V? I can't find good pictures of these things anywhere online. It's like pulling teeth.

Paul, do a search on Ebay "clark 5 speed" and the top one that pops up is from a 57 Chevy 2 ton. That might help you out. My Clark (out of a 69 Ford bread truck) has a serial # tag on the passenger side up towards the top. I would love to adapt mine to my engine since it is an overdrive tranny.

That was a good idea, but I didn't find one that looked quite like mine. Maybe I'll try to get rid of the nutria nest so I can pull the tranny tunnel tomorrow and get a better view.

if yours is anything like mine, spray the screws holding the cover down with penetrating oil, dig out the screw heads with an awl and then blow them out with compressed air, hut them with a hamer to loosen, and then I also crawled underneath and grabbed the threads with a pair if vise grips and broke them loose that way. Otherwise, you will strip most of them!

I saw what appears to be same or similar trans at Don Chew's place yesterday, is behind a Lincoln flathead(317), unfortunately top cover removed, only 3 shift rails, however. Send us a px of your engine if possible and that will help identify the trans.

Ed

The casting number on my engine days it's a 261. I added the pic to my gallery, should be the first one.

Paul,

Are you going to use it? Do the ratios matter or the function or if synchro or not? Why not get and get a guarantee rebuild able? Since 261, will fit most GM engines.

Ed

I plan on using it if it works for my purposes. I don't want to spend a lot for a different one yet, and I have no reason to believe that this one is deficient yet. I just like to know what I have, I guess. I've ID'd my rear end ratios and engine, and am just trying to put together the rest of the pieces. It may help characterize how the truck should perform before I put it on the road.

I could potentially live without synchro gears, and I like the idea of a wider gear spread. My old sm465 really only had 3 usable gears in most situations. Unfortunately my wife's car broke down yesterday, so I may not get to play with the truck anytime soon.

Take a look at the unique PTO opening on the driver side. It sure resembles yours which suggests it is a Clark 205 or a 207.

https://plus.google.com/u/0/1126369...1958379762&oid=112636930370126476644

Ken,

It sure does look like the Clark in your book, that would make sense too since it is paired with a GM engine.

Ed

Ken,

Thanks so much for posting that, I think we have a winner! Now I just wonder if I'm lucky enough to have a 205VO/207VO, or if I'll just have a 205V. I'll have to get a helper to watch the driveshaft as I turn the motor over by hand. Maybe I can determine if the top middle gear is "4th" or "overdrive".

It is indeed a Clark...

They have an awkward shift pattern

R 2 5
1 3 4

Are the 205 and 207 Clarks different from the later clarks? This site is showing 1st and reverse on the right side.
http://www.chevyc60.com/the_transmission_page.htm

That seemed right to me, since I can feel a spring I have to overcome to get to the right side. I think my choices will either be:


2 4 R
|_|_| Direct Drive 5th
| | |
3 5 1

OR

2 5 R
|_|_| Overdrive 5th
| | |
3 4 1


The latter pattern would be the overdrive version. The numbers in red would be 1:1 in either shift pattern. What they're really doing in the OD version is taking what used to be the direct drive 5th gear and saying it's 4th, then regearing 4th to be an overdrive instead of an underdrive.

Is the tranny in your 55.2 Chevy 6400, or another truck ?

The problem with any 5 speed OD trans, is to make 5th OD in the direct 4th gear position, is they make OD the 3rd gear position, so there is a tremendous gap between 2nd and 4th, with a load, one cannot frequently make that jump to 4th., unless a two speed rear, so one is 2nd gear bound until the road levels out.

Makes it even worse with the closer ratio gears required with a diesel. On my 1 ton KB-5 with a 345, I changed out the trans to a direct 5 speed and changed the diff. ratio, much more useable setup.

Ed

Yeah, so far that's the only old iron I have.

The old Clarks had the shift pattern you posted. The good thing about them was that if you got stuck, you could go back and forth from 1 to R and try to rock yourself out. Overdrives were very rare. Chances are good you have a direct.

Well I managed to rid the truck of its infestation related debris and get the old carpet out. The tranny tunnel came out without too much fuss. From the top, the tranny looks even more like the 205/207 case. I wonder if there were any castings or stampings that would differentiate them. I do see a couple castings in the new photos toward the end of the album, but don't know what they signify.
5 speed pics

Casting numbers won't do much good because the direct and OD are built in the same case. 50 years ago it was common to change a few gears in a Clark and make an OD out of it. GMC would have a line set inside the glove box door. I don't know much about Chev. If all else fails put it where 4th would be on a direct.



2 4 R
|_|_| Direct Drive 5th
| | |
3 5 1

Turn the input shaft. If the output goes slower than the input, you have a direct. If it goes faster, you have an overdrive.

4 shift rails and Al top cover sure clues. 540 series as well as 465’s are all easy to downshift into low, just practice.

Ed

Does have provision for PTO on both sides which the NP540 has.

You do realize this is a 6 year old thread, right?

Mike B

Still working on days of the week, now you want me to notice the year?