Shifting An Old Wide-gear Tranny

[linesplice]

I got myself a fairly old truck recently that has a very wide range 5-speed tranny. What's the trick with upshifting without grinding the heck out of the gears? Downshifting with a double-clutch is no problem. The thing is, I've lost all forward momentum by the time the engine has spun down enough for the next gear to want to engage without grinding. What's the trick? Any advice would be appreciated. Thank you!

[Lmackattack]

The mack 5 and 6 speeds make long slow shifts if you dont use the clutch brake. If im heavy or on a Ramp I will short shift 1-2-3 (without help from the clutch brake)and then wind the hell out of 4th and stay there untill its flat ground. Most steep hills I pull I wont shift past 3rd. I can make it to the top of 3rd but trying for 4th is not going to get me there any faster and will just cause me to louse momentem.

as far as the grinding. a little light pull on the stick is ok. You will feel a slight grind and as it slows it sould fall right in to gear. the old mack engines like to lug low 1100 -1200 rpm is where it makes its power. if it is not pulling out of that rage just stay there or downshift back to the next lower gear

[Maxville Truck]

Is it a low RPM motor? if so turn your rpms up it helps.... for some situations, or an engine brake would assist also...

[linesplice]

The engine will turn about 2000 RPM, but the more RPM you give it, the longer you have to wait for the RPM's to drop so you can put it in the next gear up. No engine brake, so it sounds like I just have to wait for the engine RPM's to come down before I can get it in the next gear?

[GearheadGrrrl]

Sounds like you've got a Maxidyne engine, in which case the operating range is either 1200-2100 RPM (ENDT 675 or 676, EM7) or 1000-1800 RPM (EM7L). Most of the Maxidynes used the higher RPM operating range, but there was a low RPM version built from the late 1980s throught the late 1990s. Being yours won't rev beyond 2000 RPM I suspect its the low RPM version.

The transmission you have has very wide ratios- for example if you upshifted @1800 RPM the next gear will bring your RPM down to a bit over 1000 RPM. Thusly it takes a while for the revs to drop, but don't try to hurry the process. It helps a lot if the clutch brake works, but virtually every Maxidyne I've driven had no clutch brake left. With no clutch brake you'll be OK upshifting on the flats, but if you're going uphill and the truck isn't gaining much speed you may as well stay in the gear you're in and make the upshift when the road flattens out.

[linesplice]

I saw a video on YouTube of a guy banging through a quadraplex tranny, no clutch, like it was butter, and though I know I don't have more than 5 gears and a 2-speed rear, I'm grinding the teeth right off everything but the 1-2 shift, so I figure I am doing something awful wrong. Maybe not though from the sounds of things. I don't see how I would get anywhere with even a small load. Patience is truely a virtue I'll have to learn.

[MACKS]

Why are you guys talking about a clutch brake to shift a tranny? Neaver engage the the clutch brake while the truck is moving, The clutch brake is only for when your at a dead stop, If your drive shaft is turning the gears in the tranny are turning and you can't stop them with the clutch brake.

[HK Trucking]

I got myself a fairly old truck recently

Why not enlighten us as to exactly what kind of "old truck" you have, and then perhaps we could give advice more specific to your actual situation.

When you say that the engine takes a long time to idle down, that suggests to me that it is an old Cummins with the PT fuel system. Those were notorious for that.

In any case, it ain't gonna go in gear without grinding unless the RPM's of the engine exactly match the road speed for the gear you're trying to shift into.

[twostickmutt]

yeah hk. nothing like a 1955 A-CAR with a 220 and a 5 and 3 in it when i first started. only two good shifts in the whole thing was 4to 5 and direct to over. some of those changes you could eat half of sandwich while waiting but you learned how. the truck kept moving but not fast. worst one i ever drove was a '56 R-220 binder. you talk about sraight gears 3rd to 4th seemed minutes.

[Rob]

yeah hk. nothing like a 1955 A-CAR with a 220 and a 5 and 3 in it when i first started. only two good shifts in the whole thing was 4to 5 and direct to over. some of those changes you could eat half of sandwich while waiting but you learned how. the truck kept moving but not fast. worst one i ever drove was a '56 R-220 binder. you talk about sraight gears 3rd to 4th seemed minutes.

I've never driven that combination before but I can tell you I could have "catnapped" in between the upshifts on my first R model with a 237 and a five speed. Never did really get the hang of it before needing the engine for something else.

Rob

[Maxville Truck]

Ive got several of these low speed engines.. everyone has a T2060 transmission. Patience is the only alternative to shifting these. My conditions were such that once we got a gear and went off road... we have to stay in that gear. I did turn my Rpm's up on all the motors, which helps in some situations, We have live hydraulics driven off the crankshafts.... I can stall a hydraulic cylinder out which helps pull down the rpm's but i'm the only one who knows that trick!!! (gonna keep it that way too!) a set of dynatards or jakes would help though!!

[Joe Ditchkus]

Macks. I am with you as you stated the clutch brake is only for putting trans in gear when in neutral and completely stopped I have to believe the drivers that read the post missed that comment about using the clutch brake when moving. That is why there was no clutch brake left for whoever posted on the trucks they drove.

Edited April 1, 2007 by Joe Ditchkus

[mudslut28]

Trying to use a 2 piece clutch brake with the truck moving will usually result in it laying in the bottom of the clutch housing back in 2 pieces...lol. Clutch brake is only for getting it in gear while sitting still.

[HK Trucking]

I saw a video on YouTube of a guy banging through a quadraplex tranny, no clutch, like it was butter, and though I know I don't have more than 5 gears and a 2-speed rear, I'm grinding the teeth right off everything but the 1-2 shift, so I figure I am doing something awful wrong. Maybe not though from the sounds of things. I don't see how I would get anywhere with even a small load. Patience is truely a virtue I'll have to learn.

Since we still don't know exactly what kind of "old truck" he is referring to, I re read this post and apparently the truck has a 5 speed trans. and 2 speed rear.

This would pretty much rule out any of the Maxidyne setups, unless someone had swapped in a 2 speed rear later on.

Clutch brake use is definitely a no no for shifting.

I used to drive Maxidyne equipped trucks in the hills of CT and NY and always got 'er done without a problem.

Wonder if his truck has a dragging brake that is causing it to lose road speed quicker than the engine can lose RPM's?

Many variables here.

[twostickmutt]

if he's got a 2speed axle he ought to be able to do a little splittin'

[JD 5020]

Have you tried double clutching on the up shift, with out giving it an extra throttle? I know it works well on a quad box when shifting the main transmission.

[71tanker]

gotta grind em till ya find em, that was the advice i got when i was learnin

[twostickmutt]

just knocking the rust off

[Freightrain]

I saw a video on YouTube of a guy banging through a quadraplex tranny, no clutch, like it was butter,

.........um..........that'd be me in that video. It's a triplex, but that don't matter much.

It's really simple to do when you don't have any rpm to deal with. Those little diesels run like a gasser and you can flip thru the gears pretty easily with only 300 rpm drops. And lord knows I done ground all the burrs off when I first got the truck and didn't have a CLUE what I was doing LOL!!! (but don't tell anyone)