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Old 03-21-2024, 01:17 PM   #1
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T444e + Allison 2000 revving too low at highway speed?

Hello everyone!
Yes, it's been a minute since I've been active here. Life moves fast and an all sorts of directions.

This summer I lost an injector and ... now I have a newer T444e paired with an Allison 2000 (5-speed) installed in the bus with overdrive. The old transmission was a Spicer 5-speed without over drive.


(more details here https://www.skoolie.net/forums/f27/a...tml#post507739)

The Allison's 5th gear ratio is 0.71 (I think); the diff ratio is 4.33. While comfortably cruising at ~105-110 kph the RPMs are ~1700.

Is this safe for the long term? It doesn't have much power in the top gear and downshifts on most ant hills. That's not a big deal, honestly, but I'm wondering what of the two options I should look at:

1. Drop a 4.78 ratio diff into it. I'm not sure what the donor bus has, but it did feel like a higher diff ratio than my active bus. If I'm lucky I can snag the carrier from that one.

2. Increase the power of the engine. I don't mind purchasing one of those programming tools (a cheapo clone). If I increased power and watched EGTs do you think I would keep 5th gear better while going up small hills?

Or are there other ideas out there?

Also, I'm disappointed in the 1st gear take off. Best I can tell, the torque converter stall speed falls just short of the turbo spool RPM. Would an increase in engine power help me much with power from dead stop?

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Old 03-21-2024, 01:30 PM   #2
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I used this tool for these numbers: https://spicerparts.com/calculators/...rpm-calculator


Diff gear ratio: 4.33
Tire height: 41.3in
Engine RPM: 1675
Transmission gear ratio: 0.71

Vehicle speed: ~67mph / ~108kph





Diff gear ratio: 4.78
Tire height: 41.3in
Engine RPM: 1850
Transmission gear ratio: 0.71

Vehicle speed: ~67mph / ~108kph
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Old 03-21-2024, 02:19 PM   #3
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the T-444E definitely likes to be in the 1700-1900 range mininum.. and on any kind of incline or such it likes 2000-2200 or so if being pulled..


this is why having a 6 speed is paramount over a 5.. mine currently runs really low.. it was a 70 MPH bus before i swapped in the 6 speed allison.. now I tach about 1550-1600 at 65 MPH. in 6th.. and about 1700-1750 in 5th at 65... i have smaller tires.. but my plan is to go from my 3.54 to a 4.10, doing so will get me in that 2100 or so in 5th gear and bac into the 1800-1850 range in 6th.. the small difference is an easy program change in the TCM so i can base it on my engine load factor to drop from 6 to 5.. in my case a 0.61 to 0.71 range change.. having to drop all the way to 4th is a huge change... 0.71 to 1.00, I just need to take the time to buy a chunk and swap it out
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Old 03-21-2024, 02:56 PM   #4
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Hello cadillackid! I was hoping you'd weigh in


So maybe I'm not doing too bad with my flat-land cruising speed of ~1700rpm. Up a hill it operates between 2200-2500rpm (I think).

In regards to keeping that RPM in 5th gear, do you think increasing the engine HP from it's current 175hp to 210hp will help it operate in that range? I mean, I would presume so. With that approach, would I notice much difference off-the-line?

I recall that you have much experience tinkering with the ECM settings...
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Old 03-21-2024, 03:08 PM   #5
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I'm going to grab a Nexiq USB link 2 knock-off from aliexpress anyway.. I don't know why I don't have one yet. Maybe I thought they didn't work with the older 3-box ECM/VPM/IDM that I no longer have
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Old 03-21-2024, 03:56 PM   #6
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going up to 210 will definitely help. (going up to 350 with big HPOP and injectors will REALLY help and with an RPM like 1700.. if you crunch down on the accelerator enough it should still downshift into 4 for climbing. , if its not then there may be a comms issue or such someplace..
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Old 03-21-2024, 04:12 PM   #7
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Quote:
Originally Posted by cadillackid View Post
going up to 350 with big HPOP and injectors will REALLY help
Haha I bet! I don't see that in my future, though.

I'll at least bump the HP to 210 and see how I like it before doing anything mechanical. Do I need the "Engineer" unlocked version of Servicemaxx for that tweak? If so, where can I get it? The pirates in the bay don't appear to have it.
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Old 03-21-2024, 04:40 PM   #8
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Quote:
Originally Posted by jazty View Post
Haha I bet! I don't see that in my future, though.

I'll at least bump the HP to 210 and see how I like it before doing anything mechanical. Do I need the "Engineer" unlocked version of Servicemaxx for that tweak? If so, where can I get it? The pirates in the bay don't appear to have it.

Ive got it in my "bay" but have to figure a way to get the large file out...
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Old 03-21-2024, 04:46 PM   #9
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Originally Posted by cadillackid View Post
Ive got it in my "bay" but have to figure a way to get the large file out...

Using a file-sharing service like google drive, MEGA.nz, dropbox, or something else along those lines usually works pretty good.



Obviously Google and other Big-Tech platforms are likely to spy on you, which can present other issues down the line, but I've personally used Mega.nz because it's pretty secure and has a focus on encryption that many of the others lack.
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Old 03-22-2024, 08:45 PM   #10
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gearing

Cadillac and I are pretty close to the same, 25,000#, 4.33 with 42" tires, 6 speed but I have more power, DT466 turned up to ?what? I dont downshift until a pretty good hill which is perfect in my thoughts. I am turning 1550 at 70MPH. You need more power to compliment that drivetrain or drop your gear ratio a little.
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Old 03-23-2024, 08:01 AM   #11
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EGT trouble is the main thing you can run into by crowding the engine.. you can hear it when it feels crowded or lugged.



regardless of the numbers geeks with TQ/ HP charts, and bore / stroke, under square vs over square yada yada.. my experience has been in the real world than an inline 6 will pull hard at lower RPMs when compare to a 'V' engine.



the early versions of the 466 (pre 94) were really long stroke low end brutes.. the 'NGD' that came along in 94.. (and the same short block was kept for the 466E up till 04). went to a bigger bore and shorter stroke.. im not sure why navistar went away from the large bore.. I havent kept up on rick's build enough to know which engine he has.. but if he has a DT466C with a 5.3 inch stroke no wonder he never has to downshift.. a 4.3 x 5.3 engine is a torque monster but going to run out of juice above 2100 or 2200.



the DT466 is a brute at low RPM.. at 1600 RPM it gives you great pulling power as long as you have a turbo that makes enough boost to burn the fuel.. you can keep opening the low end of the pump and it will take it and not scream too much.. if you are black smoking then its too much or if you can hear it really start to growl then its time to go down a gear.. I likie the allison's approach with double overdrive as the 6 to 5 downshioft is close enough it wont rev you to the moon but will take you up enough just to make an engione happy again if its complaining or if the EGT gauge is creeping...



the T444E (and really any V is a different story.. 1600 RPM is only good for light loads.. the stock turbo IH put on the vast majority of the T444E's (standard torque from 94- 2002.5) is a non waste-gateed 1.0AR/1.0AR GTP38 .. its a good solid reliable turbo.. they dont die very often.. but they also dont make any boost at low RPM.. so when you fiuel a T444E heavy on the low end with a heavy load(and the HEUI system even on stock HPOP and injectors is very capable of fueling heavy).. you just run the EGT to the moon.. the T444E is a wierd bird in that it likes RPM to make power but not too much RPM or it makes an incredible amount of heat and goes really inefficient..



navistar revs them to a max of 2600-2700 ... ford rev'd the triple 4 to 3400 redline.. I changed my governer to 3200 and reset all my shift points for my 4th gear to 5th to play with the thought of running higher revs asnd shifting into the power band.. of course me being over-geared.. the one issue is that to get the bus to 3100 RPM meant i was hauling ass at 75 MPH in 4th gear.. boost at 32+, EGT's on the march but the power felt "flat".. the GPH from the computer showed it was still fueling heavy..just starting to back down for the governor. once I got into 5th.. I had to back out of it for a bit to get the EGT down but then it pulled hard again as i took the bus on up to 80 for a brief time... from what ive seen the T444E likes a light load in that minimum of 1700-1900 (assuming it has low enough gears to get out of its own way if you crowd it a bit).. and under a moderate load you need to be 2000-2200 or so.. thus why I feel the oinly swap worth really doing on the 444E is a 6 speed.. gives you the flexibility to keep it where it likes to be..



with a 5 speed you'll never keep it happy for all situations.. 5 to 4 is too steep to run highway speed in 4th and still keep it happy medium in 5th..



the DT466 is more forgiving as most I6 engines are.. you can pretty easily build a 5 speed ratio set to keep a 466 happy.. a 6 speed allison behind a pumped-up 466, you have a cake with lots of icing on it...



the only thing more versatile would probably be a 10 speed stick.. gear it such that your first couple are brute gears that you may not use every day.. and your top 3 are highway cruising gears (7th would get to 60 MPH).. you'd have 8-9-10 to choose for your terrain..
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Old 03-25-2024, 08:49 AM   #12
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Quote:
Originally Posted by cadillackid View Post
the only thing more versatile would probably be a 10 speed stick..
I was just looking at the different Eaton 10-speed gear ratios and shift pattern to see if I would like it.

The 10-speed I was looking at had a normal H shift pattern. Row through the gears 1st to 5th like a normal car; then switch to "high" and row through the gears again for 6th-10th. Pretty straight forward.

I really do miss having an extra-extra low gear. That 10-speed having lower gears than the Spicer (and much lower than the Allison) is so sexy.

Based off of my old Spicer 5-speed's gear ratios I could start in 4-low/5-low somewhere around there, using that as "1st" gear. Then I could go directly to 6 gear and shift normally up to 10th. Interesting..

Still, for now I will see what a HP increase on the engine gives me.
This T444e does come with a turbo with wastegate. I'm not sure what the numbers are on it, but if anyone is interested I will go outside and grab the details.

I'm looking forward to seeing what a power increase can do for my first gear take off, too.
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Old 03-25-2024, 09:19 AM   #13
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in actuality I would probably go with a version that has a top gear as 1:1 vs overdrive.. and then gear tall on the rear end.. this reduces your driveshaft speed..



driveshaft speed is important when trying to solve noise / driveline vibration issues..



overdrive simply means that the driveshaft spins faster than the inoput shaft on the transmission..



with a 10 speed that has top 1:1 ratio and a tal lrear end gear you have plenty of gears to downshift into for pulling hills.. and on the low end.. your low range 1 - 3 is lower than most any automatic out there so you wont need to worry about being too tall geared to pull a heavy load off from a stop..



the only downside some people see to eaton fuller units is that most are non synchro so you have to master the art of floating gears or double clutching.. not hard when you make the effort to learn it but many feel its daunting.. and maybe nowadays you can source synchro versions.. ive never driven any that were...



and the final thought is that just because you have many gears doesnt mean you have to use them all.. I have skipped gears in stickshift cars for years.. you dont always need them all and nothing is hurt by not using them all.. if you are running light on flat ground or on a decline you very well may be able to go every other gear for a couple... and you likely will only need 1-3 in low range (maybe never) once in a while... although on an incline starting out those low range gears are really nice to get you rolling forward (and not backward) and getting out of the clutch quick... something really nice for a person who is somewhat new at driving a manual...



the number one fear of anyone learning a manual is rolling back into the car behind them at a light, or stalling on take off..
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Old 03-25-2024, 10:00 AM   #14
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A 10 speed would rock.

Currently your Allison 4th is like your 5 speed in 5th. Direct drive.

All bus applications I have seen had a 5.63 or in that ball park with the Allison 2000.

I say ballpark because we had a 2004 T444e and a A2000. It did not have a N190 in it but a 5.57 Rockwell in it.....

If I had the time I would have taken the whole diff for swapping.
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Old 03-25-2024, 11:27 AM   #15
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Quote:
Originally Posted by cadillackid View Post
and the final thought is that just because you have many gears doesnt mean you have to use them all.. I have skipped gears in stickshift cars for years.. you dont always need them all and nothing is hurt by not using them all..

I know this all too well I drive a Toyota Echo 5-speed and for quickly getting up to highway speed I run out 3rd gear then double clutch into 5th. Max HP in that car is right up at red line haha. It's a fun go-kart.


The donor bus seems to have around a 5.78 diff ratio. If it was 4.78 I'd be out there pulling it right now!
Using this calculator https://spicerparts.com/calculators/...rpm-calculator , I don't think it's quite what I'm looking for.
I'll try to make this current config work for now. Sourcing a "perfect" rear end is not going to be easy in my neck of the woods.
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Old 03-25-2024, 11:53 AM   #16
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Quote:
Originally Posted by jazty View Post
I know this all too well I drive a Toyota Echo 5-speed and for quickly getting up to highway speed I run out 3rd gear then double clutch into 5th. Max HP in that car is right up at red line haha. It's a fun go-kart.


The donor bus seems to have around a 5.78 diff ratio. If it was 4.78 I'd be out there pulling it right now!
Using this calculator https://spicerparts.com/calculators/...rpm-calculator , I don't think it's quite what I'm looking for.
I'll try to make this current config work for now. Sourcing a "perfect" rear end is not going to be easy in my neck of the woods.
Grab you vin number and call the dealer to know the true diff ratio.

My 5.63 runs at 2200 RPM or so if I remember correctly at 100kph on 10 inch tires. 5 speed Allison 2000. Would have liked to gone to 5.38 I believe it was when my diff blew up......just to expensive.
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Old 03-27-2024, 05:39 PM   #17
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Talking

If you like manual shifting - have a look at the ZF-Ecosplit16 series transmission. There are loads of versions - from 1600nm to 2800nm.
There should be one that fits your bus....
Used market is full of the older manual shifters.
Obviously 16 speeds is overkill for any bus, but you certainly never again have NOT the perfect gear!

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Old 03-27-2024, 06:09 PM   #18
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Quote:
Originally Posted by cadillackid View Post
in actuality I would probably go with a version that has a top gear as 1:1 vs overdrive.. and then gear tall on the rear end.. this reduces your driveshaft speed..



driveshaft speed is important when trying to solve noise / driveline vibration issues..



overdrive simply means that the driveshaft spins faster than the inoput shaft on the transmission..



with a 10 speed that has top 1:1 ratio and a tal lrear end gear you have plenty of gears to downshift into for pulling hills.. and on the low end.. your low range 1 - 3 is lower than most any automatic out there so you wont need to worry about being too tall geared to pull a heavy load off from a stop..



the only downside some people see to eaton fuller units is that most are non synchro so you have to master the art of floating gears or double clutching.. not hard when you make the effort to learn it but many feel its daunting.. and maybe nowadays you can source synchro versions.. ive never driven any that were...



and the final thought is that just because you have many gears doesnt mean you have to use them all.. I have skipped gears in stickshift cars for years.. you dont always need them all and nothing is hurt by not using them all.. if you are running light on flat ground or on a decline you very well may be able to go every other gear for a couple... and you likely will only need 1-3 in low range (maybe never) once in a while... although on an incline starting out those low range gears are really nice to get you rolling forward (and not backward) and getting out of the clutch quick... something really nice for a person who is somewhat new at driving a manual...



the number one fear of anyone learning a manual is rolling back into the car behind them at a light, or stalling on take off..
The Mercedes Actros manual transmissions are full syncro but hard to find on this side of the pond, plus I think that they will be cost prohibitive.
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Old 03-28-2024, 08:45 AM   #19
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Most all Euro trucks use ZF, except Mercedes. At the end it doesn't matter. The "problem" is with newer equipment inevitably you will have electronics involved. Most new trucks with "automatic" transmissions (pretty much ALL of them by now) don't have a (your bus Allison 6-speed style) automatic - they have the good old 10-, 12-, 16-speed Ecosplit with computerized shifting, double clutch and all!
No doubt, IF you transplant a whole new/modern bus powertrain into your Skoolie, you have the magic carpet right there (or the electronic nightmare....)
At the end, IF you go "used manual" trans - especially if you go "Euro style" - you want an older non-electronic (beyond monitoring sensors) transmission. For your bus adaption, you likely will need an bellhousing adapter, a bit of clutch work, possibly servo installation, etc...
Now if you are already willing to go that way, you might as well look for a little overkill on the trans-side, a bigger trans will likely never get to its max input, so it will likely loaf all its life in your bus, even in the crawler gears....
That Actros Mercedes might be a nice parts-bin if you find a rollover - harvest EVERYTHING, take the bus down to the chassis and mount everything Actros!

'nough said!


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Old 03-28-2024, 09:11 AM   #20
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I always liked the super 10.

Conventional 10's has you shifting 5, then splitting, and shifting the 5 again.

Super 10 splits each gear, so 1 split to 2, shift to 3, split to 4, shift to 5, split to 6, etc.
It can essentially be shifted like a 5 speed, easily allowing you to skip every other gear, because you can simply leave it in low or high range and go 1,3,5,7,9(or 2,4,6,8,10) without having to move the splitter. 10th is usually OD also.
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