I have a D-Type M-41 installed in my PV - cross posting from the PV list hoping there may be more folks with experience with M-41s.

Problem is that it is difficult to properly engage 4th gear. The (long) gearshift lever seem to travel aft the same in the 4th gear position as it does in the 2nd gear position, but the transmission acts like it's not quite getting into 4th. The transmission was purchased used from a salvage yard and luckily it functions properly; no noises, no grinding, OD engages fine - all is well except for the stubborn 4th gear engagement. If the gear lever is not put into 4th with authority it will not fully engage and pop out.

When installing this transmission into my car I had to drill & tap a boss on the cover to accept the 4th gear lock-out switch, which was sourced from a spare M-40 I had from a '75 240 sedan. Interestingly enough, there are switch actuating tabs mounted to both the 3-4 and reverse shift rods, yet the cover only had a boss for the OD switch, and the reverse light switch is located in the aluminum shift rod cover mounted on the aft of the transmission. Definitely a mix-match of parts but it seems to work ok.

I had written to the Brickboard before asking if there were some ideas of what the problem could be & the responses all pointed towards something preventing the shift rod from going full travel, and the probable culprit was the 4th gear lock-out switch. Yesterday I removed the transmission to inspect. First off, the parts on the shifter itself seem to be in fine shape; a good fit between the spherical ball and the top cover, no excess wear on the roll pin or its mating slot on the cover, and the gearbox end of the lever shows no wear. Before disturbing the gearbox top cover I removed the shift rod cover on the back of the transmission, reinstalled the gear shift lever, and engaged 4th gear to determine if the rod was going full travel, and it was. Next I removed the top cover and studied the movement of the shift rod, shift fork, and engagement collar. It seemed as if the collar wouldn't engage the 4th gear dogs positively unless the rod was almost completely in the engaged position; if the rod was aprox 1/8" from the fully engaged position, i/e., the detent ball bottomed in the V-notch of the shift rod, the gear didn't engage. More inspection revealed that the set screw for the shift fork was not tight, requiring about a quarter turn to seat. Another thing I noticed was that there seemed to be a large amount of clearance between the shift forks and the engagement collar. It is difficult to get a feeler gage in there but I would say the clearance is around .040" - .050". I have a couple spare M-40s and they appear to have similar clearances. I've been trying to find specs for the parts but have not had any luck so far. I played around with the lock-out switch and found that it will impede movement of the shift rod if installed without the gasket and the cover gasket, but not with it assembled correctly.

So I guess the problem is related to the lock-out switch impeding movement, the loose screw on the shift fork not locating the fork correctly, or too much clearance between the shift fork and the 3/4 gear engagement collar. Perhaps it is a stack-up of all three, but without any spec on the shift fork/engagement collar clearance I can't eliminate that variable. Hate to reinstall the transmission without checking all the variables. Any help appreciated.

Thanks,

Joe in St Louis