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M41 versus M410 transmission

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26K views 27 replies 7 participants last post by  nadanutcase  
N
#1 ·
OK guys, I am back for further enlightenment:

About a month ago I ordered a gasket set for what I thought was the M41 transmission in my '70E and dropped them off for the guy at a local shop who's replaced the bearings in it. He got back to the project today and called to tell me that almost none of the gaskets, except maybe the one for the top cover, would fit. I double checked the invoice then called Christer at VP-Autoparts who immediately said that I might have an M410 and that it would be OK to send them back for a refund because he doesn't have the gaskets for a M410. He seems like a genuinely nice guy and I continue to think highly of VP-Autoparts.

I called the transmission shop again and he looked around and did find an M410 reference on the bellhousing, so it seems that is indeed, what I have.

I've seen references to the M410 as a possible swap out for an M41, but hadn't dug into it at all. I thought it was a possible transplant from a 164 but in the little time I had this afternoon to search the net a bit I found a Wikipedia posting that said that for some reason a FEW 1970 1800's were built with the M410. That it's more heavy duty and capable of handling more torque than an M41 BUT that the bearing life is barely that of the M40..... heavy duty, but not as durable
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I suppose I could buy them somewhere, but the trani guy said he makes gaskets all the time - it just takes more time of course - so I told him to proceed with making them. I'd also given him a set of gaskets and seals for the J-type overdrive, and they are OK, so I'm covered there.

I guess my questions come down to three:

1) Any idea why volvo engaged in this little experiment? Maybe they had a problem getting some M41 parts for a while or something?

2) What's your reading on the "tougher but less durable" bit?

3) Since I like to have a full set of manuals if possible, and the ones I've downloaded for the 1800 and the M41 specifically don't cover the M410, do you know where I can download that manual?

Looking forward to a long Easter weekend; I hope to spend a fair chunk of it under and in the car putting things back togother - and I have a lot to put back togother at this point.
 
G
#2 ·
Re: M41 versus M410 transmission (nadanutcase)

From Phil Singher on Swedespeed...

--------------------------------------------------------------------------------------
... the M410 was used with a B20 only in the 1800E throughout '70 and early '71 production, and it's not the same M410 used with a B30. Volvo went back to the M41 mid-'71 in B20 cars.
-------------------------------------------------------------------------------------

More...

http://home.avvanta.com/~volvo242gt/Volvo140.html

George Dill
 
W
#3 ·
Re: M41 versus M410 transmission (gdill2)

As nearly as I can tell the differences between the 4-cylinder M410 and the 164/B30 M410 are in the bellhousing and the input shaft, with the rest of the tranny being the same.

The bearing problem was an internal lube issue that caused noisy operation after about 100,000 miles or less. In my experience the noise is the majority of the problem. I've been driving one with a noisy tranny for a long time and it works fine except for needing new piston rings on the OD actuating pistons.
 
N
#4 ·
Re: M41 versus M410 transmission (gdill2)

When you say "throughout '70 and early '71" I assume you mean off and on through that period since there don't seem to have been too many of them put in 1800's. I cruised back through the manuals I have and didn't find any reference to other the M40 or M41 in the 1800 specific service manuals. It seems odd that Volvo would skip over the M410 in the 1800 service manuals if it had been used for more than a production year. In the overdrive manual they do show a type J on an M410 and of course there are refences to that combination in other models.

Regardless, it seems that's what I have and it's nice to know that al though I hope I'll not have to do anything to the transmission again for as long as I'm around.
 
N
#5 ·
Re: M41 versus M410 transmission (Walrus3)

As soon as this came up I wondered about that input shaft because I'd read about people who were in the process of transplanting an M410 needing to use a different clutch disk. Last Fall when I pulled the transmission out I decided to go ahead and order a new clutch and pilot bearing since it makes little sense to go through that much work and NOT replace them even if they had been working fine. Of course what I bought was for a '70 E with the M41. It turns out that the new and old disks and bearings are the same. So as you say it seems the input shaft is the same as the M41. Maybe this is an M410F where the F stands for Frankenstein ??

It's also interesting to hear that you've had bearing noise that long with no problem since it was that noise that caused me to get into it in the first place. For what it's worth I have the old bearings and the two smaller ones, those from the gear cluster shaft, are noticeably rougher. Not sloppy or loose but rough enough to sound off. Who knows how long they've run like that with or without the ATF I found in the trani?

Someday, just to satisfy my curiosity, I'd like to learn why Volvo bothered to do this since the M41 was fine as far as I can tell.

++++++++++++++++++++++++++++++++++++

ONE MORE THING sort of related to this discussion - when I swapped out the pilot bearing I found that there was no snap ring retaining it even though the manual calls for one and the crank has a groove for one. It doesn't seem like there'd be much motivation for it to walk out the end of the crankshaft anyway, but I figured it couldn't hurt to use one. I didn't have one that large on hand so I started looking around town. It seems that every shops' snap ring kit jumps from 1 1/4" to 1 1/2" and what I need is 1 3/8" or pretty close. I haven't beat ALL of the bushes yet but It would be annoying to get the transmission back from the shop and be hung up on this. The old one didn't need a retainer... what do you all think?
 
W
#6 ·
Re: M41 versus M410 transmission (nadanutcase)

If the clutch plate fit the input shaft you have the right one. The B30 input shaft is larger but an M40/41 input shaft is not right for the M400/M410 tranny.

The "snap ring" is a lot like the one used to retain the felt seal on your timing cover (different size). In other words it is just a plain wire ring with one end bent inward so you can get something under it to get it out.
When you NEED the snap ring is if you pull the tranny and don't pull the clutch. Did this on a 122 once and wiped out both the clutch plate and the input shaft housing because the pilot bearing was rolling around loose between the flywheel and clutch plate. Strange noises and effects!
 
N
#7 ·
Re: M41 versus M410 transmission (Walrus3)

I can imagine that was one noisy clutch for at least a little while....

I got into the whole "snap ring problem" last Sunday afternoon. Here in farm country (I live near the county seat that has a population of around 27,000) we have a number of farm supply stores with hardware supplies suitable for working on all kinds of equipment, so I hit one of those first. Then I tried three different auto parts places and had the same result. One place I didn't go was the local NAPA store because they were closed. I was on my way to open up my shop at 8 this morning and caught the NAPA guy just after he opened. He pulled out his snap ring kit and the first one I picked was what I needed. So it'll be captive after all. Not that it would be likely to go anywhere anyway. I had to use a puller to coax the old one out and while I didn't exactly wail on it, the new one had to be set into place with a few taps of my favorite BFH and an appropriate sized drift.

Now I just have to get the transmission back - I haven't heard from that guy yet. I suppose he's busy making gaskets - and figuring the bill.
 
T
#10 ·
Re: M41 versus M410 transmission (nadanutcase)

I have owned both.

From what I understand, some of the earlier M41s had a habit of leaving second gear in the street. While the redesign was going on in 70-70, they got the M410 from an outfit, I believe in W. Germany.

Couple obvious differences, the bell housing bolts to the transmission from inside the bell housing (means you want to pull the transmission, you take the bell housing with it ... cant access the bolts to separate them until the assembled unit is off.

If you look at the two side by side, the M41 case has a support rib diagonal across each side. The M410 has a smooth case.

Parts and most gaskets are not interchangeable.

The M410 is considered stronger and some racers swear by them. Once I got one with the bell housing for $100.00 yet saw a bell housing alone sell on one of the parts sites for $500.00 (you gotta have it ... you gotta have it
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The one I had I sold to a guy in Australia (who races 1800's) ... lets just say shipping was more than I charged him.

Believe the drive shaft is the same, so just a M41 and bell housing is required to swap them out ... no secret tricks or rare parts.

Parts are very hard to get ... many are no longer being made. If I had a 410 I guess I would drive it, but would keep my eyes open for a good M41 at the right price and have it in the corner.

If I remember right, they are also known, upon acceleration, to scare dogs and old ladies due to the scream of first to second (a problem that could be eliminated by over powering it with the sound of a straight threw 2.5" exhaust :

Steve
 
N
#11 ·
Re: M41 versus M410 transmission (Tiredtrader)

I got my rebuilt M410 back from the shop Friday and got it (mostly) reinstalled this weekend, but there's much more to do before I can road test it as I also got all of the gauges rebuilt this winter and need to put the dash back togother among other things. The guy at the transmission shop had no trouble finding replacement bearings and wound up making the gaskets. Everything inside the trani and overdrive looked good. I'm looking forward to NEXT weekend as I plan to take 4 days off and spend much of it in my shop.

If I saw a real bargain for an M41 (with bell housing) I might buy it, but I plan to use my car mostly for a weekend driver so I expect all I've put into the driveline (all new trani bearings, new speedo drive & cable, new clutch- pressure plate - pilot bearing, even a new clutch cable) will last as long as I need. I plan to drive it, not flog it.

BTW, for those following this dialog, after chatting with Irv Gordon regarding transmission maintenance, I elected to use 75W-90 synthetic lube in it since I'll use it during warm weather only and don't care about cold weather overdrive performance.
 
W
#12 ·
Re: M41 versus M410 transmission (nadanutcase)

With ALL due respect to Irv and what he has successfully used in his car, YOUR tranny has different problems. One of the problems the M400/410 trannies have is difficulty getting adequate lube to some of the bearings. A thicker oil will make this WORSE. As a guy who has worn out a couple of those trannies with moderate driving, I'd say use what the manual for a car that has an M410 calls for. My 1972 164 manual calls for SAE 30 or 20W-40 motor oil for the M410.
 
N
#15 ·
Re: M41 versus M410 transmission (Walrus3)

Yeah, given what I have heard about the M410 since I discovered I have one (specifically the bearing problem) I've been thinking hard about the whole lube thing again. And, of course, the provisional manual for the 1970E DOES call for SAE 30.

A couple questions:

1) Can I assume that you were using 30W during the time you wore out a couple transmissions?

2) Does the '72 164 also use a Laycock overdrive? Or did Volvo stipulate 30 W, in any of there car using the Mxxx transmission without an overdrive?
 
W
#16 ·
Re: M41 versus M410 transmission (nadanutcase)

All M410s have the Laycock-DeNormanville type J Overdrive.\
The M400 is the same tranny without OD. They call for 80W gear oil, which is not much different from SAE 40. The first one I wore out was actually an M400 and it had 80W gear oil. The second one was an M410 and it had SAE 30.
 
N
#17 ·
Re: M41 versus M410 transmission (Walrus3)

George - The more I dig into this subject, the more intersting it gets.

Your last post kind of confirms what Irv Gordon and my earlier reasearch had led me to conclude. It is the Laycock overdrive and not the transmission itsself that made Volvo spec SAE 30 W. Granted Irv is running an earlier M41 with a Laycock type D overdrive rather than a type J. Before our last exchange I'd bought some 70w-85 synthetic gear oil. Out of curiosity, I visually compared a sample of it and 30 W Castrol motor oil and was surprised to find that, at least visually, I could see little, if any difference in the apparent viscosity. The synthetic gear oil is also notable in that it doesn't smell like the traditional Hypoloid oil I know we've all had on our hands - and that I remember as being more viscous at room temperature. ANYWAY, I was curious and yesterday at the shop it was kind of slow so I started looking for a simple viscosity comparison test that I might try to prove or disprove my visual impression. That lead to some interesting reading on the different kinds of viscosity and how they're measured, but the most interesting point were statements and charts in a couple places stating, as you just more or less did, that SAE 30 MOTOR oil has pretty much the same viscosity as SAE 80 GEAR OIL. So in terms of potential viscosity induced bearing starvation in the M400 / M410 it appears they're about equal. Here is a link to an interesting, and not too long or mathamatically opaque, report I found :

http://micapeak.com/info/oiled.html

I am honestly not trying to be argumentative about this; it's just another example of how a seemingly simple question can have a surprisingly complex answer.

Since you've had experience with both combinations, I have to ask if the M400 with 80W or the M410 with 30W lasted longer? Or were they about the same?
 
W
#18 ·
Re: M41 versus M410 transmission (nadanutcase)

Kinda hard to say, especially since we are talking about years of time and two different countries and one tranny dealer rebuilt in Panama....
I'm not sure that I could really express a preference.
I'm wondering if there might be a simple mod to the tranny that would improve the lube and thus the life. Not being too much of a tranny guy (and especially not to eager to do research on them at this late date!) we may never know. Maybe some of the racers could shine some light on this. The M410 in my 164 is noisy but shifts and runs OK. The OD needs new O-rings to engage reliably. I got it used from a guy in central PA 25 years ago - he shipped it to me in Panama in 2 boxes through the APO.
I put it together in my carport and put it in and it worked OK for quite a while. OD started being intermittent in 1998 but it has not been used much on the highway since then.
 
K
#19 ·
Re: M41 versus M410 transmission (Walrus3)

FWIW my 1970 P1800E has a M41. I am not sure at what points during the 1970 model that Volvo substituted a 410.

From http://volvo1800pictures.com/

it appears about 5000 P1800E's were produced for 1970.

Starting at chassis 30 001. Mine is 30 461 so it is near the start of the production run for that year. Perhaps they ran out of the M41 at some point after that?
 
K
#21 ·
P
#22 ·
Re: M41 versus M410 transmission (ktm_525)

Note that when those sites say something was introduced in '69, that means for the '70 model year. My take on the subject, as best I know:

M41 strengthened for the '69 model year, along with the introduction of the B20 and J-type OD.

ZF-built M410 used in the '70 model year 1800E, continuing into early '71 production. It was never used in any other 4-cylinder model.

'71 model year (except for some early examples) revert to the M41 with a further reinforcement of the second gear. This continues through the '72 model year.

'73 ES models have the M41 with a lower ratio on the first gear. This continues through the end of the M41.
 
K
#23 ·
Re: M41 versus M410 transmission (Phil Singher)

Quote, originally posted by Phil Singher »
Note that when those sites say something was introduced in '69, that means for the '70 model year. My take on the subject, as best I know:

M41 strengthened for the '69 model year, along with the introduction of the B20 and J-type OD.

ZF-built M410 used in the '70 model year 1800E, continuing into early '71 production. It was never used in any other 4-cylinder model.

'71 model year (except for some early examples) revert to the M41 with a further reinforcement of the second gear. This continues through the '72 model year.

'73 ES models have the M41 with a lower ratio on the first gear. This continues through the end of the M41.

That is what I understood but my 1970 P1800E has a M41. About 400 cars into the production run for the year? Perhaps a running change for 1970 and the early run got the original M41? Side note is 2nd gear is just fine.
 
K
#25 ·
Re: M41 versus M410 transmission (Phil Singher)

Quote, originally posted by Phil Singher »
Are you sure it's the original transmission?

No. But it only had about 75k miles on it. Judging by the leaks and the old gasket I assumed it was original but it could be a replacement. Replacing a 410?

We need a roll call. 70 owners, declare your transmission.
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N
#26 ·
Re: M41 versus M410 transmission (ktm_525)

I am the one who kicked off this particular exchange when I learned of the M410 used in my'70E after pulling it to replace the bearings and mistakenly bought a gasket set for an M41. For what it's worth I'll mention that while it was apparently made by ZF, the transmission case casting does say VOLVO on it. I imagine in a side-by-side comparison there'd be several noteable differences, but for those '70 owners who want to check the easiest difference to spot is probably how it's attached to the bell housing. If your trani bolts to it from the outside (so you can pull the transmission with the bellhousing left on the engine) you have an M41, whereas if the mounting bolts are from the inside of the bellhouse, you have an M410.
 
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