Need some trans info

[xdudebrahx]

This is in a 77 Canadian R612. Shift pattern seems to be the standard H with the dog leg over and back towards your leg. Has R N L D on the air shifter. Also has a small lever next to the main box and I can't figure out what it's for. Doesn't even seem like it moves. Can't find a shift pattern sticker in it. Anyone venture to guess what the shift pattern is?

[Freightrain]

My guess air shift 6spd?

The little lever likely a brownie box. Look under the truck for another transmission? If it didn't get used a lot, the linkage might just be gummed up.

[2stacksuperdog]

Possibly the old style 12 speed that have a shifter for low low instead of air switch on dash

[masterwelder]

That sure sounds like a Mack 12 to me. I think you use the small shift lever in reverse and L on the air shift as a deep reduction. Otherwise just normal shift 1st low/ high 2nd low/ high ect. I think...

[Challenger]

If its a 12 speed the shifter towards the left is for deep reduction and will only move while the main shifter is in 1st gear. If you attach a picture of the trans from underneath the truck, some one can tell you what it is.

[xdudebrahx]

I'm home for the day. If I'm not busy tomorrow I'll see if I can snap a pic of underneath. I only got in it to take it over to the pressure washer. I've kind of "adopted" it and I'm trying to clean it up real nice. Hate seeing our old stuff get neglected.

[Maddog13407]

Oddball . Most 612s had a r1110 roadranger

[cecilktm]

Looks like a 12 speed with the extended range on the extra stick instead of a dash switch (see shift pattern below). Also, looks like the truck has a Maxidyne 300 based on the air cleaner, assuming it's original. In lieu of the the typical 5 or 6 speed lo-hole, it's got to be the less common 12 speed paired with the Maxidyne.

[xdudebrahx]

Looks like a 12 speed with the extended range on the extra stick instead of a dash switch (see shift pattern below). Also, looks like the truck has a Maxidyne 300 based on the air cleaner, assuming it's original. In lieu of the the typical 5 or 6 speed lo-hole, it's got to be the less common 12 speed paired with the Maxidyne.

Mack 12 speed shift patter.png

Thanks! Exactly what I was looking for.

[Vladislav]

Looks like a 12 speed with the extended range on the extra stick instead of a dash switch (see shift pattern below). Also, looks like the truck has a Maxidyne 300 based on the air cleaner, assuming it's original. In lieu of the the typical 5 or 6 speed lo-hole, it's got to be the less common 12 speed paired with the Maxidyne.

Mack 12 speed shift patter.png

The air cleaner seems as a typical Canadian one.

[cecilktm]

The air cleaner seems as a typical Canadian one.

I don't think the type of air cleaner has anything to do with the truck being Canadian or not. R model air cleaners with two air ducts coming out the front would be an indicator that the truck had a Maxidyne 285 or 300 with tip turbine / coolpower set-up. One air duct goes directly to the intake side of the turbo and the other goes directly to the cool air side of the heat exchanger. I haven't seen any other type of Mack engine using this type of dual duct air cleaner, but I also haven't spent too much time in Canada.

I only mentioned this at all because it would have been a non-typical powertrain combination to have a 12 speed transmission mounted to a Maxidyne 300 engine. The high torque and long powerband of the Maxidyne did not need so many gear ratios, and the whole selling point of the engine was to cut down on the number of gear shifts needed when accelerating or decelerating.

If in fact Canadian R models had two air ducts coming out of the air cleaner for some other reason, then I'd be interested in understanding why.

[Underdog]

I've seen some in colder climate have an air cleaner with an intake tube routed from under the hood, to draw warmer, drier air. That appears to be the set up on this truck.

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[39 Baby Mack]

I've seen some in colder climate have an air cleaner with an intake tube routed from under the hood, to draw warmer, drier air. That appears to be the set up on this truck.

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The first R models had air cleaners like that, there was a cable to control under hood air or external air.

Ron

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[39 Baby Mack]

I don't think the type of air cleaner has anything to do with the truck being Canadian or not. R model air cleaners with two air ducts coming out the front would be an indicator that the truck had a Maxidyne 285 or 300 with tip turbine / coolpower set-up. One air duct goes directly to the intake side of the turbo and the other goes directly to the cool air side of the heat exchanger. I haven't seen any other type of Mack engine using this type of dual duct air cleaner, but I also haven't spent too much time in Canada.

I only mentioned this at all because it would have been a non-typical powertrain combination to have a 12 speed transmission mounted to a Maxidyne 300 engine. The high torque and long powerband of the Maxidyne did not need so many gear ratios, and the whole selling point of the engine was to cut down on the number of gear shifts needed when accelerating or decelerating.

If in fact Canadian R models had two air ducts coming out of the air cleaner for some other reason, then I'd be interested in understanding why.

This truck also has a hood scoop on it too. The scoop would be for the tip turbine fan. The second pipe on the air cleaner would more than likely be for under hood air supply in cold weather.

Ron

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[cecilktm]

I've seen some in colder climate have an air cleaner with an intake tube routed from under the hood, to draw warmer, drier air. That appears to be the set up on this truck.

Sent from my XT1254 using Tapatalk

Thanks Underdog.

[Dirtymilkman]

In cold weather you'd draw air from under the hood to warm the engine up quicker. Or in heavy fine snow you draw from engine compartment.

[xdudebrahx]

Would this truck have had a 7 speed in it with a lo-lo stick? Two low gears and 5 direct gears? Didn't get to mess with it yesterday and I had to take off today to get some teeth yanked out.