I pulled the driveshaft and m40 transmission, put the m40 next to the m41 and measured the difference in length, which was 11.375". Does that sound about right?

Anything else I should be thinking about? The flanges match ok.

I'll drill and tap the boss on the old cover to accept the o-drive lockout switch.
If you know the tap size that would be helpful.

Or if any has a front section of driveshaft, that would work too, but I still think I'm going to have it balanced at the shop.

Thanks in advance.

Mpergielwalkermi1968220.

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MPergiel, Walker, MI

Call me I'm in Walker 784-9190 Dick

I have 11 5/16"/28.7cm as the amount to shorten an M40 shaft. 11.375" is only 0.0625" longer so good to go I'd think. This is for a D type OD. The J type is longer by about 0.5cm. Apologies for the mixed imperial and metric measurements.
The tap size has been posted here but I don't have it written down.
Shortened should be balanced as 1 piece and then with the rear part as a complete shaft. Remember to get the U/J's in proper alignment, in-phase, when fitting. New bearing and mount a good idea too. Good luck.

Thanks.

I once had the intermediate mainshaft bearing fail, after being noisy on deceleration. The big ball bearing one at the back of the transmission, in front of the overdrive. I was thinking of replacing that bearing just as prevention.

Has anyone else seen that failure?
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MPergiel, Walker, MI

I can't say there is a pattern failure of the rear mainshaft bearing.

All I can say is that we always replace that bearing when rebuilding an M40/M41. And in fact we have rebuilt two M41 transmissions in the last 2 months.

FYI, you have to remove the mainshaft from the transmission to replace the rear bearing and you have to remove the overdrive as well.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com

I had mine done at D & R driveshaft Chicago Dr. Jenison

But they said they couldn't even fit it on the balancer.
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MPergiel, Walker, MI

My local (Grand Rapids, Michigan) driveshaft shop won't touch it. All they do are trucks.

I'm thinking of having my machinist/welder take a look at it and maybe sleeve it.

Otherwise I need the part from one of my community friends. ;)
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MPergiel, Walker, MI

Hello,

I found a couple of driveshaft repair shops in the the Rapid City, MI area.

Did you call the one in Jenison, MI?

If you can't get someone local to do the job, I use a place close to me and they aren't afraid of a Volvo driveshafts even though most of their business are big rig trucks.

They aren't cheap, but they do great work and in fact I am about to have a driveshaft re-made for a customer to fit his 1966 Volvo 122 with an overdrive due to bad driveshaft yokes on both driveshaft halves.



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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com

I had my machinist shorten the driveshaft. He cut 10 3/8 out, turned one of the ends down to fit inside the other 1 inch, then nicely welded a bead around the outside.

11 3/8 seems fine, but I wouldn't go shorter. There is about a half inch of mounting leeway at the center support.

The center joint had a plug where the zurk was, so I just put in a zurk, greased it, then replaced the plug. The joints all seemed fine, not stiff or floppy. I replaced one of the spiders, which seemed to have a open hole where the zurk went, just to be -nal. I used the supplied zurk to pump it full of grease then replaced it with a 10-28 setscrew. The zurk impinged the movement. The parts guys laughed at how tiny these joints were, but I'm sure that minimal rotating mass makes balance less of an issue.

The tranny lid: I drilled out the boss then made up an m16 tap out of a bolt and tapped it out for the lockout switch. I'd recommend an actual tap with the correct size drill. It is NOT a 5/8 thread.

Filled the tranny with 30wND. 1.8 qts or so.

I wired a lighted toggle switch, toggle relay to the lockout it all seemed to make the right clicks. I test drove it to the grocery and got it up to 55 or so, the odrive and driveshaft seem fine. It's a d-type. Shifts firmly right in.

All I have to do now is move the toggle slightly left so I can see the green light, that, and tidy it all up.

I can see (hear) that wind noise will be an impending issue, but the heater works and doesn't leak.


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MPergiel, Walker, MI