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Discussion Starter · #1 ·


The photos are blurry, but bear with me. I finally pulled the trigger on a manual tran setup. Found a guy on Craigslist with a very tired 122 coupe who had spare M40, and an entire M40 setup in the car. We chatted a bit and came up with a fair price, and I came away with both transmissions, both bellhousings, the flywheel, pressure plate, clutch disc, a newer clutch master and slave, the pedal cluster (including accelerator), shifter, driveshaft, and trans crossmember ... plus a few other pieces. Came to $300 total, which seems like a good deal considering that by grabbing all the good bits from a single car I don't have to try and piece together it all from different and possibly incompatible parts.

Both transmissions look to be in fine shape, although the one in the car was indescribably filthy. The donor car had been stored in a leaky garage, with a floor covered in a thick layer of oil-soaked cat litter, for what looked like a century and a half. I've never seen so many spiders. It was very miserable to remove all the parts, but now it's done.

I'll try to take a bunch of photos and document how this goes, so hopefully I can answer questions for anyone else who tries this swap. The BW35 is coming out this week while I order a new clutch kit and bearings, and send the flywheel out to the shop to be resurfaced. And then it's modifying the crossmember, which shouldn't be too tough. More to come.
 

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He'll have to shop for a whole M41 tranny. The OD requires tranny parts and adaptations that are not part of the standard M40.
 

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Discussion Starter · #4 ·
Yeah, for the record, I'm intentionally not going for a M41. I'm staying M40 for the time being. I don't plan on being on the freeway all that often, I don't trust the Laycock OD units to not break and cost me lots of money suddenly, and I like the charm of a 4-speed. Plus I have the auto rear ratio so it shouldn't be too bad with a 1:1 4th gear.
 

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Discussion Starter · #5 ·
I should ask, though, because I've never actually had to do a clutch job (let alone one on an older car - I've had my Mazda for 5 years and the clutch is still great):

Do I need to use new hardware for the flywheel? for the driveshaft? For the clutch? I saved all the bolts that came off but I don't know if they're intended to stretch when torqued and therefore not reuseable.

I did see that IPD sells driveline flange bolts in both sizes, and I might get new ones just for the heck of it, but I didn't see flywheel bolts or clutch hardware listed on IPD or on Swedish Treasures.
 

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Discussion Starter · #7 ·
OK - first real question. I appear to have a driveshaft center bearing mismatch.



The one I just pulled off my car, the shorter BW35 driveshaft, is on the left. Note the rubber donut thing that supports the center bearing, and the easily removeable rear driveshaft segment - it just pulled right out. The manual driveshaft that came off the donor car (I believe a '64) is on the right, and it had the kind of center driveshaft support that has two pins. I was planning on using this when I put in the M40.

First question: can I disassemble the driveshaft and put the rubber donut style center bearing on the longer driveshaft?

If not, can I swap out the part on my car so as to use the longer driveshaft as is?

Lastly, if neither of those are an option, do I just get my old shaft lengthened?

PS - my rubber driveshaft donut situation on the BW35 driveshaft is a bit torn. Are replacements available?

Thanks!
 

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Yeah, for the record, I'm intentionally not going for a M41. I'm staying M40 for the time being. I don't plan on being on the freeway all that often, I don't trust the Laycock OD units to not break and cost me lots of money suddenly, and I like the charm of a 4-speed. Plus I have the auto rear ratio so it shouldn't be too bad with a 1:1 4th gear.
The final gear ratio (differential) is the same for manual and auto 122's. So, you have the 4.1 rear (unless somebody changed it, not likely). Your engine will be "buzzing" at 75 just as much as any M40 Amazon. But it is not really a big deal. The engine actually sounds nice, and I like the instant throttle response and the rate of acceleration until 90-95 (a bit over 5000 rpm). If you are on the freeway for long periods of time, then it may get tiring. But for a little bit, its OK. I think that if the Laycock fails, it still works on 1:1. Also, the main benefit of the M41 is when you also have the 4.56 rear ratio (installed in the factory with the M41), which really improves low speed acceleration over the M40. Also, the 4.56/OD will give you much better acceleration in OD and high speed cruising than with the 4.1. With the 4.1+OD, you may not be able to do much better than 80-85 even with a mild head wind or slight incline (unless you have a well build B18B or B20B).
 

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Discussion Starter · #10 · (Edited)
Hmm, interesting. I actually have the opposite problem - I'm trying to keep using the "donut" style bearing. That is "native" to my car - a '67. The long M40 shaft has the older style yoke because it came from an older car. While the rear sections of both look to be roughly the same length, unfortunately I need to use a long front shaft to mate with the M40 I'm putting in, and it's the front section that carries the bearing. I guess the question I need answered is, if I unbolt the two bearing/yokes, do they come off the driveshafts so they can be swapped? If I can unbolt the yoke from the newer driveshaft and bolt it onto the older one, that would solve my problem.
 

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Discussion Starter · #11 ·
Here's another question. I picked one of the M40s and started getting it ready - cleaned the outside, drained the old fluid, scraped the gasket surfaces, installed a new top cover gasket, and put it all together with the proper amount of GL-4 85W-90. Then I put some wood down and put it on its bellhousing to install a new trans mount where the crossmember attaches.

After I was done, a fair bit (half a thimblefull) of trans fluid had leaked out of the input shaft area. So, my question is, the transmission isn't supposed to be up on end, but should it still leak from there? I wonder if the input shaft seal is bad. Should I replace it or is this normal?
 

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Here's another question. I picked one of the M40s and started getting it ready - cleaned the outside, drained the old fluid, scraped the gasket surfaces, installed a new top cover gasket, and put it all together with the proper amount of GL-4 85W-90. Then I put some wood down and put it on its bellhousing to install a new trans mount where the crossmember attaches.

After I was done, a fair bit (half a thimblefull) of trans fluid had leaked out of the input shaft area. So, my question is, the transmission isn't supposed to be up on end, but should it still leak from there? I wonder if the input shaft seal is bad. Should I replace it or is this normal?
I'd replace it while it's out either way. You'll be cussing it when you're back under there pulling the whole thing back out to do one tiny seal. Plus it's super easy but be sure to get the o-rings that go on the three allen screws as well.

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Discussion Starter · #13 ·
I'd replace it while it's out either way. You'll be cussing it when you're back under there pulling the whole thing back out to do one tiny seal. Plus it's super easy but be sure to get the o-rings that go on the three allen screws as well.
Fair point. I took those three screws out and tried to remove the input shaft cover. Tapping with a rubber mallet and lightly prying with a thin flathead didn't do the trick. I wonder if I need to be more forceful with it. Is there a trick I'm missing? The Volvo service manual didn't have any helpful tips. "Remove input shaft cover" is their instruction.
 

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Fair point. I took those three screws out and tried to remove the input shaft cover. Tapping with a rubber mallet and lightly prying with a thin flathead didn't do the trick. I wonder if I need to be more forceful with it. Is there a trick I'm missing? The Volvo service manual didn't have any helpful tips. "Remove input shaft cover" is their instruction.
It might need a little help but it should come off. Those manuals are notorious for describing things that "should ease off". Yeah. Right. Maybe in 1967.

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Discussion Starter · #15 · (Edited)
Quick update: got that sucker off finally. Could not figure out how to get the input shaft seal out. Used a input shaft bearing cover with a good seal, cut a new gasket, and sealed it up. Got everything else back together and put it on the jack. Guess what? Slipped right into place the first shot. Looks great. Still need to modify the trans crossmember and hook up the driveshaft, but virtually everything else is close to being done. Thanks for everyone's help.
 

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Quick update: got that sucker off finally. Could not figure out how to get the bearing out. Used a input shaft bearing cover with a good seal, cut a new gasket, and sealed it up. Got everything else back together and put it on the jack. Guess what? Slipped right into place the first shot. Looks great. Still need to modify the trans crossmember and hook up the driveshaft, but virtually everything else is close to being done. Thanks for everyone's help.
How did you get the input shaft bearing out without dropping the layshaft?

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Discussion Starter · #17 ·
I didn't - the bearing itself was fine, but the nose of the trans was leaking oil. I had a used bearing cover that had a decent seal. I cleaned it and put it on. So the input shaft bearing was never removed. I was going to replace the seal but couldn't get it out without damaging it, and I had a good one sitting around. Nothing appears to leak. If it does, I'll drop the trans again - PITA but I might have to do that anyway, no clue as to the condition of this trans although it looked ok when I peered into it with the topcover off. I have a spare trans that I think I'm going to actually seal up properly and keep as a spare in case this one's crap.
 

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Damn I was hoping for some good news for me, lol. Well that's good you got it all back together. I still haven't been able to find the drift for retaining that layshaft.

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You should take the parts to an engine or tranny shop, they'll have enough universal tools that they'll be able to press it apart for you without the special tool. Probably charge less than the tool costs too.
 

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Discussion Starter · #20 ·
OK, a couple of quick questions:

For modifying the M40 crossmember, I was thinking of using some angle iron. What size should I get? I'm happy going a bit thicker/wider for some added rigidity because it'll be cantilevered out a bit.

Also, what size is the hole in the trans tunnel of a manual car for the shifter? I'd like to be able to use a stock shift boot. There's incidentally a hole in exactly the right spot for the shifter already, it's just about an inch or so too small to accept the threaded part of the shift lever. I want to get it sized correctly so the shifter can move around without banging into the tunnel.
 
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