What Transmission is designated the HD 3-speed Manual

[rechinca]

Ok, first I am not at home for a few days and have been trying to do some research with zero luck (including the search function).

I have no way to look at the truck for several days and want to know what transmission was designated as the H.D. 3-speed with the 350 for 1971? This was spurred by knowing the rear seal is leaking and I want to replace it, but just doing some parts research some places specify not for HD. Looking to find make/model and I thought I had seen somewhere it was a Muncie, but of course I am search function challenged now and can't duplicate it for some reason.

[100%Chevy]

I believe it is a Muncie.
In 65 or 66,GM developed a new heavy duty 3 speed manual for use with the new big block 396's in the cars.
I think yours would be the same if it helps.
Mike.

[weim55]

HD 3speed in your '71 should be a Muncie M13. Lookup the thread '3OTT question HD' I posted a pic there.

Steve weim55 Colorado

[rechinca]

Mike and Steve thanks for the information! Now I can’t wait to get home tomorrow finally and confirm with pics. Amazing how you get those questions stuck in your head when you have no way to get under it, in it or around it to confirm and have down time at work.

[rechinca]

I’m dragging this back up for another couple of questions. Are these M13 HD 3 speeds that hard to find? Second would be does it take a different bellhousing than the Saginaw 3 speed? I ask because I would like to get back to having this transmission eventually, but my current setup is a 350 from a ‘72 Chevelle from what I have gleaned from the numbers so I am guessing the Saginaw came with it since my SOID soec’d The HD 3 speed.

[projectking]

I remember a trans that had a peak on the top of the bell housing mating surface that I believe was the HD version.