doubleclutchinweasel

Wow! That's way too early for my limited knowledge! Hopefully, one of the guys who is more into the older stuff can help. Welcome aboard, anyway!

Exactly. Keep the Maxidyne up in the 1800-2100 RPM range, and it is well off its torque peak, which was down around 1200 RPM. It's only when the RPMs start to fall that the increased torque of the Maxi becomes prevalent. And, like Terry said, if it's just a toy, and isn't too heavy, it probably won't be an issue anyway. But, if you're gonna work it, just keep the RPMs up in the normal Thermodyne operating range, and drive is sensibly, and it should be fine. That being said, the 676 still is a monster, torque-wise. Look at the graph below (for a 285 HP version). Even at 1800 RPM, it's still got 825 ft-lbs on tap. That was more than most transmissions of the day were rated for. Hence the triple-countershaft Maxitorques. I wouldn't jerk it too hard! I have heard of several folks running a 237 in front of these boxes, and that works very well if you stay out of the fat part of the torque curve.

Or here...

I think the U and DM were the same exact cab. 'Couse, I never swapped one out, though.

Start here...

18-speed Quadruplex. Double over. Adds the lo-lo range. Still has all the Bulldog Cool of having 2 sticks. Real Macks need 2 sticks. Not necessarily if you're gonna work them, but definitely if you play with them! Loved the RoadRanger that came in mine, although it was direct (no over). But, hated not having both sticks... Okay, so I have a little masochist in me!

Not sure if this helps anything, but the range shift on the 15-speed Fuller I had did not want to shift when I first started the truck. I had to sit there in neutral and flip the hi-lo several times to get it to shift. Once it shifted, it was good for the rest of the day, even if it was cut off and restarted. This was a lot more noticeable when it was cold, and nowhere near as pronounced when it was hot. I believe I had a slave valve gummed up, preventing proper air flow to the shift cylinder. That truck had a little oil in the air system, and I believe that oil was causing the slave valve to be stubborn. These air-shifted puppies can be picky about clean/dry air.

Ah! Got ya.

Maybe 24" circumference (8" diameter)??? Is that a single-chamber or a split tank?

One gorgeous R........

удачи

Dang, that's cool. I love the old steel dash trucks. And, that one's a little better than mine was! LOL!

Sounds like the hi-lo synchro is disengaging... Could be the synchro ring or the gear it engages on the mainshaft.

Wow! That's funny, Hippy! Welcome, Matt!

I'm just repeating what the instructions, which truck shop posted, said. On my Spicer, you had to remove the lock plate, too. Whatever...

Ouch!

That's pretty cool, Bob!

You may be correct.

More??????

Probably did not happen in every state. Where I grew up, it was a normal thing.

Yep. Remember it well. Thomas Built Buses had facilities in High Point, NC. Blue Bird had facilities somewhere in GA. So, we saw a lot of chassis and new finished buses in this area.

Yip. They’re pretty good.

If so, there was another discussion...

Somebody had this on Pinterest, or somewhere. One nice-looking crackerbox. Seemed like we were discussing these a while back, but I forgot where! Looks like it may have center point steering. Poor man's power steering.