I've been scouring the internet and Classicoldsmobile, but haven't had any luck trying to find detailed info on my M41. If you don't mind, I was hoping someone here might be able to help. Here are my questions:

1) The 1969 L32 455/390 hp was only available with one transmission; the M41 Heavy-Duty TH400. Also The M41 was the only transmission available with the L32 and not available with any other engine. What specifically made this transmission special? All I could find were generic, vague terms such as "Higher line pressure" "higher shift points" and "firmer shifts", etc.

2) How did this transmission compare to other HD Olds transmissions such as those used behind the W30 and in the Hurst/Olds?

3) What stall speed converter would Olds have used for the L32/M41 combination?

Any help would be greatly appreciated.

Many Thanks!
Uncle Hulka

 

The B body M-41 uses a long tail shaft. The A body M-41 uses a short tail shaft. The valve bodies & clutch packs were the same in the ones that I have had apart.

 

I appreciate the reply, Dave. I knew the trans was a long tail (medium tail) since it came from a B-body. Because of the additional length I'll have to have the driveshaft shortened.

The M41 TH400 is different than the M40 TH400. The M41 was never available in an A-body because the L32 was never available in an A-body. Here's how the engine and trans were described in the Olds Dealer New Product Guide for 1969:

Engine, 390-hp Rocket 455 V-8 H.C. (L32). . . Heavy-Duty Turbo Hydra-matic 400 (M41) and Heavy-Duty Engine-Cooling Equipment (Y72) mandatory.

Note: The L32 option added $141.13 to a Delta 88 and $77.93 to the Custom & Royale

Transmission, Heavy-Duty Turbo Hydra-matic 400 (M41) . . .For use with 390-hp Rocket 455 V-8 H.C. Engine (L32) only.


NOTE: The M41 option (in any Delta-series) added $242.88 vs. $227.04 for the M40

Hope this helps.
Uncle Hulka

 

Ok. I should have been more detailed & careful with my above post.


The M-41 that I had came in a 1970 Delta 88 4 door. It was a 390 hp W-33 equipped car with dual exhaust. The car also had a 2.93 posi. This car was a gift from Oldsmobile to a retiring Olds Engineer. That GM employee married a lady from Calgary & ended up retiring in Alberta. About 2002 I ended up with the car & parted it out. I still have the broadcast card from the car.


The M-41 had the same set up inside as the OW Trans that I have seen apart. I sold the trans & it was converted to short tail shaft set up & added the speedo gear. It is happily living in a bracket car today. The W-33 engine is in a 1969 442 in Calgary. The guts from a posi went into a 1970 B/C Hearse that I used to own & sold.


So I suspect that the M-41 & the OW code T400 are the same deal just with different converters & governors. Hope this clarification helps.

 

Now we're talkin, Dave! Had no idea you owned this combo. Great info. I suspected it was similar to the W30 & H/O.

Now the big question: Any idea what the stall speed for the converter would be? If not, is there any way to determine this by visual inspection?

Thanks, Dave!

 

I have parted numerous 1967-1970 Olds 88s. The M-41 converter looked no different from the countless long tail shaft M-40s that I have pulled from other cars. I suspect that internally it was likely a higher stall speed but can not confirm this. When I got the W-33 car it was no longer operational.


The S manifold went into my 1969 Delta Royale to facilitate dual exhaust on that car. I remember I paid $800 for the car.


I will look for the broadcast card when I get home (I am out on an Oil rig). Across the car was hand written the word "Pulled". I took to mean that this car was pulled from the assembly line for some purpose which made sense since it was given as a retirement gift to the employee.

 

Would the info I'm looking for be found on the build sheet?

BTW, one of my very best friends (and a serious gear head) used to work for a company called Telleco. The made fairly sophisticated equipment for oil drilling equipment. He spent a fair amount of time on rigs back in the 70's-80's. He has some great stories from those days!

Thanks, Dave!
Uncle Hulka