I'm piecing together an M41 that I acquired recently and which came in many pieces all in a box. I was just kind of playing with all of the major pieces in order to figure out what I might be missing and such when I discovered a possible problem.

I found that the three control spindle/rods that go through the top of the case fit through just fine, but the spindle/rod which goes through the countershaft-gears at the bottom of the case is slightly larger in diameter than the control rods and would not fit through its bottom holes at the bottom of the case. Must this spindle be strongly forced through its holes, or might I have a spindle/rod from a different transmission, say an M40?

-A

Sounds to me like a real good start would be to go out and getcha a set of accurate dial calipers and measure the holes and the shaft... ITs a good tool to have around anyhow. Harbor Freight sells cheapo ones but they seem accurate.

Being that all the parts were supposedly just an abandoned project, I've gotta think that they all came from the same gearbox...

If it turns out your shaft is a different size for sure and won't work, let me know... I've got several M40s in various states of disrepair and/or disassembly, and I probably have a spare one of them, and maybe other stuff as well if you need... But I'd need to know the exact measurements.

One clue besides the Jtype OD to tell if its early or late is the reverse gear... The early ones have a gear whose teeth fall off straight on both sides. The later units have a reverse gear whos teeth sides are angled on one side... effectively making each tooth a little wider, hence less likely to break (though it didn't help in my case)

-Matt

Yah, I wasn't really fooling myself that I could get it back together and going by myself. I'll probably take it to a reputable place or person who can do the job right. I just wanted to see what parts I did and did not have. I hate being taken because of a lack of knowledge... so I try to learn as much as I can.

I looked at the reverse gear and it's angled... that and the J-type OD that came with it would point towards later-type M41.

Thanks,

-A

Yup... you gotcha a late one. Which is good I think... the big parts problem is them damn laygear needle bearings. I couldn't find 'em anywhere when I did mine... so I put used ones in there.

I'm the same way with the learning thing... Though maybe a bit backwards. I was going to have my transmission professionally rebuilt, but when I found those bearings to be unavailable, I said screw it, and I did it myself. The only reason for my teardown was to replace a broken reverse gear, and I did get that done.

I've got a strong hunch that you could do it too, but as I said in an earlier post... its a heck of a lot easier to start with a practice box. As I recall, you are in the Seattle area? Geez... you'd think out htere, you'd easily be able to source a used M40 for next to nothing and take it apart/put it together for practice. I'd shoot to find one from a '73 or so to be sure its the later type... then you've got spare parts. I don't know when the cutoff year is though... if there was one. Mine is a later type as well, and was from a '71. But it was a 142e and had the J OD... for non-overdrive cars, they might have continued to use the early type for a while. I don't know if there is any way to tell early from late from the outside..

If you do that, take it apart carefully. If you do it wrong, you'll have to force things, and that will wreck parts. If you do everything in just the right order, the parts just sort of fall out and its a wonderful feeling. Whatever you do, no NOT try to force that laygear shaft out the wrong way. It won't go, and you'll wreck at least half of the unavailable bearings. Trust me on that... I know.

Go for it, man...Its fun!

-Matt

Hey Matt,

Yah, it would be a whole lot easier if I had actually been the one to take this one apart, then I could reverse the operation. As it is, I'm confronted with my first transmission ever, and it's in a jumble of puzzle pieces! I took plenty of drafting classes not long ago, and I've always been fairly good at reading and comprehending how things work, so we'll see. I do know that this M41 that I have was taken apart by a shop, so I feel fairly confident nothing was forced or damaged. I think I have all the old needle bearings also. I am at least wiser now in my advancing years and I don't try to rush or force things!...

I do have an M40, but it's under my car doing its critical job right now!...

I live in Portland actually... so I may look around and see if I can find one. The IPD garage sale's coming up also, so maybe one will be available there.

If you're in Portland, would you be interested in checking out my jumble of parts and assessing if I've got enough to give it a go? I'd bring it all to you...

-A

Well hell, you're in the vintage Volvo capitol of the world I reckon... shouldn't be a problem to find one. I'm in Colorado... not really close enough. But I'm no expert myself. I've taken a lot of these things apart (the wrong way), but I've only put one back together... and it failed after about 1 year. Though I don't think it was the fault of my assembly... more a problem wiht used parts and wrong oil.

I do have some good friends who are into old VOlvos who moved to Portland, but I don't think they toted any transmissions.. but like I said, shouldn't be hard to find one in your area. The folks at ipd and the ipd garage sale would certainly be good places to look into.

Like I said... its a fun project. And if you do take apart a box for practice, you'll be left with a perfect clutch alignment tool. And of course, the spare laygear makes a great candle holder.

-Matt

You could try giving Shayne Green a call at iPd -- he knows how these go together and might be interested in doing the job for you.

A

It has a slightly larger diameter at one end so it only fits into the housing ONLY from one end...try fitting it again and I think you'll see what I mean.

Cheers

The large end goes to the rear. You should be able to push it almost all the way through from the rear -- then you need to drive it in the last 3/4" or so with a hammer and drift.

There are two different sizes of spindle, but they are so different it would be obvious if you had the wrong one.

Well - strange. I just tried it again this morning, but neither end of the spindle-rod will go in through either hole in the bottom of the case. There is no noticable major difference in the diameters either between the rod and the case-holes. Seems like a fractional tolerance difference at the most.

I did find in looking at the spindle more closely that there is a part number stamped into one end of it. It seems to read "580808"... does that help you at all? The first number is a bit obscured by wear, but seems to be most likely a five.

-A

380808 appears to be the part number of the later model countershaft. www.gcp.se has the original parts counter microfiches online, they are a good reference for part numbers and even reassembly clues (the exploded schematics).

The earlier (smaller) countershaft had a different part number.

I recently had my early M40 (1963) and later M41 (J-type, 70-ish?) apart to swap bad M41 syncros for the good M40 ones and came across the countershaft diameter difference. I didn't measure them but it would be ABUNDANTLY clear if the countershaft size and case holes were not matching. The correct ones are a somewhat snug fit, and the larger end isn't readily apparent to the eye. You shouldn't have to drive it all the way through, though, just the last couple of inches.

Woops... I did manage to find them... they're not the easiest to navigate to though... Very nice to have however!

-A

Hello John,

I looked on the GCP site but could not find the exploded drawings. Are they under "parts info"...? I couldn't access that navigation link for some reason.

-A

The history of my M41 is that it was supposed to have come from a P1800, and the OD unit that came with is certainly a J-type, indicating that the M41 is of a later type.

I just looked closer at the spindle-shaft that I have and you're correct that the first number could very well be a 3 instead of a five. The top part of the number has been worn off some how, but now the bottom part looks more like a three. So it does seem that I have the right spindle-shaft.

I just tried again and I can't get it through however. Should it go through by a strong push of the hand, or does it take some judicious rubber-mallet pounding or something? Also... is there a way to tell which end is the slightly smaller by the part-numbers stamp on one end?

Thanks for the info, it's fun learning how one of these works.

-A

I can't recall which end was the 'big' end in mine - the numbered end or not. But in my case they slid in relatively easily over 90% of the length, and had to be tapped in the last bit. It might also make a difference which end of the case you are trying - I suspect those holes might not quite be the same size either. In other words the holes might be large and small to match up to the shaft large and small ends, so that it is snug on both ends when driven in that last inch or so.

So try both ends of the shaft in both holes on the case. If the theory is correct, only 1 out of the 4 will work.

The large hole is in the rear of the case. The spindle has to go in from the rear, with the large end going in last.

There's only a few thousandth's difference between the large and small holes and spindle ends. Only the rear 3/4" of the spindle has the larger diameter. It's designed to be an interference fit once it's all together, so you will have to tap it the final 3/4" -- sometimes a fair amount of force is required; you'll need something more solid than a rubber mallet.

It should all slide together by hand, although snugly, until you reach the interference point. You can usually identify the large end of the spindle from slight wear marks where it was driven in.

Perhaps I should try sticking the spindle-shaft in the freezer, and the case out in the sun for a while... ?!?!

Well.... I thouroughly mystified now. It will not go through from either end, either hole in the case... I just don't get it. I checked the case also, and it does say "M41" on the badge.

I guess I'm screwed? The control rods at the top fit through with precision, so I just don't get this?

The differences in countershaft spindles are year related, not M40/M41 related. At least as far as I know.

You really shouldn't need to heat/chill those parts for assembly. Are you sure the holes in the case are clean and rust free? You might *very lightly* touch them up with some fine grit sandpaper or a brake cylinder hone. Are you trying to assemble the entire countershaft assembly, gears and all or just fitting the shaft by itself?

The holes do seem slightly dirty, so perhaps I'll try to ream them out a bit with some paper.

At this point I was just trying to do a rough assembly of all the main components so I could tell if it came complete with all that I might need to have it rebuilt. I was trying to put the countershaft in, held in position on it's shaft/spindle, and then put the main-shaft in also... I'm also trying to "grok" the whole thing and how it works in the process...

-A

Unfortunately, the tranny does not go together that simply. You need to have the countershaft gear cluster laying in the bottom of the case so you can properly assemble the mainshaft on top of it. Then you turn the case over and let the countershaft slide down into position, then slide in the spindle. It's a very annoying and tedious process. I tried to shortcut that step and take out and reinstall the mainshaft leaving the countershaft alone as I wasn't doing anything with it, and found the parts just wouldn't quite go with the countershaft in position. To keep the bed bushiings and needle bearings in place (in addition to heavy, sticky grease) you'll need to cut a tube or dowel, the same or slightly smaller diameter as the spindle, just long enough to hold the end bushings in place as the countershaft slides back and forth in the case. When it drops into place you push the dowel out the other end with the spindle.

PS - Instead of typing all that out I should have just referred you to the article Phil has at the VClassics site: http://www.vclassics.com/archive/tranreb.htm

I printed it out and had it laying on the bench when I had mine apart. Very nice article.