Allison 2000 Tranny

[o1marc]

What do we know about the Allison 2000 behind a Cummins 5.9?

 

[joeblack5]

sounds like a winner to me.

later J

 

[o1marc]

sounds like a winner to me.

later J

Well that reply was certainly insightful.

 

[joeblack5]

well , what do you want to know, do a google search, allison 2000 world class transmission 5 / 6 speed with lock up ,, what do you want that there is 2 lbs of gold inside?

later j

 

[Twigg-SKO]

It's all here:

1000-2000 Series

 

[o1marc]

well , what do you want to know, do a google search, allison 2000 world class transmission 5 / 6 speed with lock up ,, what do you want that there is 2 lbs of gold inside?

later j

See, now this is much more helpful. It tells me with a possible 6th gear it would put less strain on the 5.9, making a more suitable option for my needs. I value the experience on this board. That's why I know the 545 is the least desirable. Yes, some do okay with a 545, but general consensus is it ain't the cats meow. I can google search (Thank You Twigg), but it doesn't really give me real world experience like what I get here. And 2lbs of gold in one would be a nice option.

 

[Twigg-SKO]

See, now this is much more helpful. It tells me with a possible 6th gear it would put less strain on the 5.9, making a more suitable option for my needs. I value the experience on this board. That's why I know the 545 is the least desirable. Yes, some do okay with a 545, but general consensus is it ain't the cats meow. I can google search (Thank You Twigg), but it doesn't really give me real world experience like what I get here. And 2lbs of gold in one would be a nice option.

It didn't help much.

"Possible" 6th gear might prove problematic.

6th gear would put more strain on the engine, not less, so you'd have to find out if the 5.9 can cope.

 

[Kubla]

Most allison 2000's you will find used will be 5 speeds with an .75 overdrive 5th gear, being an electronic transmission, you also need the TCU and a wiring harness that does not come with an at545 since it is mechanical. I am in the process of this swap behind a TE444 and getting the wiring harness made is costing more than the transmission and TCU did

 

[o1marc]

It didn't help much.

"Possible" 6th gear might prove problematic.

6th gear would put more strain on the engine, not less, so you'd have to find out if the 5.9 can cope.

Problematic how, unlocking that gear? Would not the 6th gear reduce RPM on the motor, thus relieving strain?
The bus in question has an oil leak, so I'm less interested in buying something that needs engine work right up front.

 

[Twigg-SKO]

Problematic how, unlocking that gear? Would not the 6th gear reduce RPM on the motor, thus relieving strain?
The bus in question has an oil leak, so I'm less interested in buying something that needs engine work right up front.

Within the spec, revs don't hurt the engine. 6th gear on the 2000 is 0.61 which is a very high gear.

Pulling that gear is more stressful than pulling 5th gear, 0.71.

Yes it reduces revs and maybe reduces fuel usage a little, but it is harder to turn which is why the highway buses generally have the bigger engines.

This is also why route buses have lower geared (higher numbered) final drives. They need that so the smaller engines can pull the heavy loads at lower speeds and highway performance is sacrificed.

If you want a reliable unit that can pull those higher gears on the highway, a bigger engine is more suitable.

So I'm not saying that there is anything wrong with the 5.9, but I am saying that it has a harder time pulling 6th gear than would an 8.3, or 7.6.

 

[o1marc]

Within the spec, revs don't hurt the engine. 6th gear on the 2000 is 0.61 which is a very high gear.

Pulling that gear is more stressful than pulling 5th gear, 0.71.

Yes it reduces revs and maybe reduces fuel usage a little, but it is harder to turn which is why the highway buses generally have the bigger engines.

This is also why route buses have lower geared (higher numbered) final drives. They need that so the smaller engines can pull the heavy loads at lower speeds and highway performance is sacrificed.

If you want a reliable unit that can pull those higher gears on the highway, a bigger engine is more suitable.

So I'm not saying that there is anything wrong with the 5.9, but I am saying that it has a harder time pulling 6th gear than would an 8.3, or 7.6.

So again, I can say while the 5.9 is not bad, it is the least desirable for my intended use, correct?

 

[Twigg-SKO]

So again, I can say while the 5.9 is not bad, it is the least desirable for my intended use, correct?

Only you know what your use is going to be like, so I can't confirm that.

It's all a compromise. You have to decide which areas of compromise are more important to you. The 5.9 is a good, reliable engine in a small to medium-duty truck especially if that truck stays fairly local.

Giving it higher gears will let it go faster, but with less "shove" behind it than a bigger engine. That might be just fine if you want to cruise the rural back-roads of America, or stay mainly in the lowlands.

If you want to maintain reasonable highway speeds in more difficult terrain, you need more power AND a flexible transmission, but if that is only an occasional thing, the 5.9 will get you there even with an AT545 behind it.

Reliability also matters to us. The more power you try to extract from any engine the sooner it will wear or break. Again, bigger wins the downside being weight, cost and economy.

School buses, our chosen platform, were specced to do a job and that is not usually the job we want them to do which is why the Trip and Activity buses command a premium.

My view, fwiw, is that the 5.9 is under-powered for a full-size but, but a much better bet in a shorty or medium size. When they were fitted to full-size school buses they were geared low and kept local. A cheap solution to get a job done. Seems like it worked because there are so many around.

T444 and DT466 are much closer to the middle of the range, so fewer compromises are required in other areas.

I solved the problem by writing down my ideal spec. for the bus I wanted. Then I was clear where I was compromising when I considered the bus in front of me, because it's not just about the drive-train.

In the end I compromised in two areas ... I paid slightly more than I had hoped and I didn't get Air-Ride suspension, but I did know what I was getting and it checked all the boxes except those two.

 

[Robin97396]

Let's just say that if you have a long straight downhill slope, that sixth gear will work fine.

 

[Kubla]

What is your current top speed at redline?

 

[Rusty-SKO]

What is your current top speed at redline?

My 24v 5.9L is capped-out at 2200 Rippem's. Would love 300 more.:biggrin:

MD 3060 trans (5th only .75), 5:18 rear 11r22.5 rubber and has more than enough pep for me at this stage. If I decide to tow is when it skews the equation, but shall see.

 

[Twigg-SKO]

My 24v 5.9L is capped-out at 2200 Rippem's. Would love 300 more.:biggrin:

MD 3060 trans (5th only .75), 5:18 rear 11r22.5 rubber and has more than enough pep for me at this stage. If I decide to tow is when it skews the equation, but shall see.

So depending on the actual tire diameter (they vary a bit), your top speed is a reasonable 69 mph, right?

My numbers are very similar, but I have the 8.3 with a 5.38 FD. I'd like 6th to drop the rpm.