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Hello, I'm currently getting parts from a 1981 c70 fmc fire truck before it gets smashed into bits and sent off on the boat.. Anyway I'm trying to figure out what transmission it has in it. My 1972 c50 identifys everything in the description and this trucks tag is lacking info for some reason..maybe they got lazy in the 80s idk....any help here would be great.

Thanks,
Mike

Mike - Can you tell us if it has a manual or automatic trans?

A quick peek on the web shows the '81 C70 primary manual transmissions would likely be an Eaton/Fuller 5 speed. The primary automatics I found listed for an '81 C70 are listed as an Allison MT640 or MT653.

I'd have to more digging to see what else I can find. The number listed for the transmission in your picture didn't come back with any listing I could find.

Yeah my 1972 c50 dump truck has this same thing but with much more "helpful" info. Haha. Yeah I tried googleing the numbers as well and was only led to some "pay for it" site. Yeah it's a manual transmission 5 speed reverse is in the top left position where 1st is in my 465 4-speed transmission in my c50. Then 1st is below reverse for that rock'it out of being stuck motion, which is nice. And the rest is usual from there. What I'd really like to know is if this trans has OD 5th. It would be nice for top end speed/mpg's. If not no big deal still have more gears to play with hauling. The fire truck 'donor' has the 427 engine in it as well which I'm getting. 350 engine to 427 should be a nice upgrade for hauling loads. I'm also getting some other parts for upgrades on my '72 c50 dump truck.

This is the info my 1972 truck has. It has all the goods. But I have already swapped rear ends from that to a t170 2-speed rear from a 1969 c60. And have some springs from another '78 I believe fire truck. They are the 3in wide springs as mine are 2.5" currently with the 3in wide auxiliary springs until I get the shackles from this fire truck once I get the engine and trans pulled first. Flip it to get the shackles off easier. Haha. Good thing about salvage yard shopping, some things can be gotten much easier.

If the fire truck has the T170 rear axle, wouldn't be a bad idea to grab it if you can, or at least the third member, because those parts aren't getting easier to find.

Mike - From what I could find, the stock 5-speed in that C70 fire truck would be a direct drive 1 to 1 output unit, not an overdrive unfortunately. Appears they are identified as an Eaton/Fuller FS-5205.

That info should help you find more detailed info on the transmission.

Gdads51, your good!!! I actually found the plate yesterday when I was disconnecting all the linkages and wiring from engine for pulling it out. It's a spicer cm5250-c. Indeed 1:1 drive. Not bad tho it's got an even lower low gear then my 465 and ple ty of splitting between, it looks to be WAY heavier duty forsure. Can't wait til I can get it shoved in my truck.... that's for another time tho. I did have some questions about that transmission tho, the pto Ports it has are 2 different sizes, passenger side is a 8bolt style and the drivers side is a 6 bolt which almost looks like my 465 trans pto bolt pattern. I'm wondering if my pto is compatible with this trans? If not I'll be on the hunt for the 8 bolt style as that's the side my dump trucks pump is on. However if my 6 bolt pto could fit the driver side port I may see if I can shift it over some.

The fire truck does not have the t170 rear end. It's a single speed square tube axle behind a auxiliary transmission so I have no clue what gearing it is. And I don't have the patients to think about trying to do that swap. I'm fine with my t170 2 speed I can do 55-60mph on highway with 9.00-20s and I'm about to have some 10.00-20's to swap out so I might gain 5 mph top end speed or at least drop my rpms down a tad at 55-60mph. But i do think there is another grain truck out there at the scrap yard with a t170 rear end that I could get...first i gotta spend the money I already had spoken for on this part of my project haha. If I had deeper pockets to reach in I'd get tons of parts just to have them cuz I'm that kind of loonytune.

Sorry correction, a spicer cm 5052-c transmission.

Mike - Thanks for sharing the info you found. It turns out that Spicer unit was an "optional 5 speed transmission (model number correction noted) for the '81 C70 and coupled with the big block engines. I've no idea at the moment what pto drives fit either port on that unit, but if I get a chance later I'll see what info I can dig up.

Enjoy your toys!

For the most part PTO's are unique to one transmission only. The PTO gears need to line up with the trans gears and they are all different. The 6 and 8 mounting bolt patterns are all SAE standard making the PTO housings mounting flanges all the same...just the internal gears are different.

What you see as an Aux Transmission is more than likely the Main Shaft Transfer Case, it disconnects the rear axle and engages the High Volume Pump when shifted between the two functions (driving or pumping).

Mike B

Well I ended up getting the engine, transmission, radiator, front axle Including springs and hangers all the way to the wheels and tires, also got the rear tires, and the rear end's spring hangers so I can upgrade mine to the 3inch wide springs and haul a tad more weight per load. I also got the bench seat, chrome mirrors, some aluminum diamond plate pre bent for the steps to give the truck some character and cover up my slightly rusted steps I got haha. Had to get the motor mounts as well cuz this engine/trans has an adapter between bellhousing which is the rear motor mount instead of mounting to the cross member like my current engine does. That's gonna be fun installing all that stuff. Those rivets are a challenge to remove I gotta say. You better be motivated to get those parts and do the swap lol. Maybe even a tad bit of crazy mixed in there too.

Yeah I wasn't sure if that was a aux trans or what. But makes sense it is a main shaft transfer case. Cuz it does run the pump for the fire hose also. Which that part of truck was a goner!! Pump was rusted out.
But are you saying finding a pto to work for this transmission will be hard? Or can I just find another truck with a spicer transmission and get it's pto? The 8 bolt since it's on the side I need. And/or could my sm465 trans 6 bolt pto work on the left side of this transmission and operate a winch or front mounted something? Dont think ill do that but if i could and I find the deal why not haha.

Mike

I've had to remove rivets on my C60 when I moved the mounts around during the Cadi V8 swap. I found the easiest way is to notch the head of each rivet crossways like a Philips screw using a die grinder. Then each of those 1/4 segments just flies right off with an air chisel. Wear safety goggles and earplugs!! Especially the earplugs, because wow does that air chisel get loud when you're subsequently knocking out the plug portion of the rivets.

I was sure grateful for pneumatic tools that day!

The PTO you need whether it's to mount on the 6-bolt or 8-bolt flange needs to be specific to your Spicer model number. The SM-465 is made by GM and nothing about it is compatible with the Spicer transmission.

Mike B

Most fire trucks used a power tower auxiliary to run the pump. I have scrapped several of the power towers because all they are good for is fire apparatus and winches.