Converting to manual transmission

mrlupr · 02-15-2021, 11:46 PM

Hello folks,

I am considering converting my bus to manual transmission.

Currently I have a 195 HP 2003 T444E with a 5 speed Allison 2000. It's a 10 window IH CE200.

Will I benefit from converting to manual? If so, what transmission and accessories should I be looking for?

Booyah45828 · 02-16-2021, 08:21 AM

What are you looking to gain from such a swap?

IMO there's no reason to swap from an allison 2000 to a manual unless you prefer to drive a manual and want to drive one that badly. The electronic allisons are extremely reliable anymore. Granted, they're not as reliable or as long lasting as a good manual used by a competent driver, but the latter is starting to become a rarity these days.

mrlupr · 02-16-2021, 09:06 AM

I was thinking I might gain better fuel economy by having higher highway speeds at lower RPMs. My Allison does not have the 6th gear unlocked.

I also am wondering if it would help me going downhill safer by giving me better engine braking capability without worrying about my transmission overheating.
I used to drive my cars in mountainous areas and remember that it was always easier going downhill in my stick shift compared to my automatic cars.
I would downshift to second or third gear and just let her Cruise all the way down.

Correct me if I'm wrong on any of these assumptions please.

Booyah45828 · 02-16-2021, 09:39 AM

What's your current rpm/mph in 5th? How fast are you wanting to go?

Your current transmission has an OD of .71/.74 depending on the model of allison. You'd have to go to a 10+ speed manual to get a lower OD ratio then that so it also wouldn't have a huge step between the gears.

Since your 2000 has a lockup torque converter, you'll also have pretty similar downhill braking performance between the transmissions, you'll just have to manually move the shifter into another position if you want it to hold a different gear and get good downhill braking.

RolesvilleMarina · 02-16-2021, 10:04 AM

Quote:

Originally Posted by Booyah45828

What's your current rpm/mph in 5th? How fast are you wanting to go?

Your current transmission has an OD of .71/.74 depending on the model of allison. You'd have to go to a 10+ speed manual to get a lower OD ratio then that so it also wouldn't have a huge step between the gears.

Since your 2000 has a lockup torque converter, you'll also have pretty similar downhill braking performance between the transmissions, you'll just have to manually move the shifter into another position if you want it to hold a different gear and get good downhill braking.

I also don't see the value if one has an A-2000 already

for an AT545 a manual swap may be better for some gear heads to avoid the laptops but in this case he may just be really really short in the rear end gearing

in which case re-gear to the 4's and fly

ABBus · 02-16-2021, 01:33 PM

I did it on my older class C motorhome. So much better. More fun, easier to go downhill, etc. ..

mrlupr · 02-16-2021, 03:55 PM

Last time I drove her I was limited to 60mph and I was a little over 1800rpm. I have since reprogramed the max speed to 75mph and I was hoping to get a top cruising speed of 65 to 70mph.

Am I asking for too much from her?

If the benefits just aren't there then I will definitely scrap the idea of a manual. If my downhill experience is not significantly improved with a swap, then I don't see the value it.

Oldyeller · 02-16-2021, 05:01 PM

What RolesvilleMarina said, regear the diff. Much less expensive and easier.

Unless you just WANT a manual in which case rational decision making goes out the window. I prefer a manual but the bus I bought came with an Allison 2000 - oh well.

BeNimble · 02-16-2021, 08:58 PM

Here is a 35ft prison bus with a manual, just buy this and sell yours. At $4,000 cheaper than modifying yours..I also think a prison bus is geared for the highway, unlike a school bus.

https://sfbay.craigslist.org/eby/rvs...270172198.html

thjakits · 02-17-2021, 12:00 AM

IF you go ahead with a manual swap - look into a used ZF-Ecosplit-16.
About every European truck has or had one before all went computerized (and it's still a the same Ecosplit just the computer does the shifting now...). They come in all kinds of torque ranges (the biggest one I ever had was in a Renault Magnum with 500 hp) - you can get them used for around $3k all day long - excellent synchronised shifting - a real pleasure to drive!

However - with your trans at hand - I'd rather look into finding a way to get that 6th gear unlocked....

thjakits

Booyah45828 · 02-17-2021, 07:55 AM

There isn't a 6th available on the 1000/2000 until mid 2005. He'll have to do a valve body, harness, and ecm swap to gain 6th. Without a donor vehicle, consider that impossible due to it's expense.

I've quoted the conversion, but have never done one. People have always found that it's easier to cruise around 65, and have a max speed of 75.

And to be completely honest, if you're only dealing with 195 hp, you're likely near your speed limit anyways. The HP required goes up exponentially the faster you go. And your fuel economy will go in the tank as well with higher speeds.

s2mikon · 02-17-2021, 08:28 AM

Read this. It gives you a good idea about fuel usage and hp required for different speeds. I have found it to be quite accurate. My coach has 4.1 gears and 11r24.5 rubber and will easily run 70 mph, but god is it expensive. And with the price of oil going up I'm not looking to go faster. https://beaveramb.org/wp-content/upl...formance-1.pdf

rossvtaylor · 02-17-2021, 08:47 AM

Quote:

Originally Posted by s2mikon

Read this. It gives you a good idea about fuel usage and hp required for different speeds. I have found it to be quite accurate. My coach has 4.1 gears and 11r24.5 rubber and will easily run 70 mph, but god is it expensive. And with the price of oil going up I'm not looking to go faster. https://beaveramb.org/wp-content/upl...formance-1.pdf

Thanks for the cool, geeky find...I'd not seen that and there's some interesting info in there. Downloaded and saved!

s2mikon · 02-17-2021, 09:02 AM

Hello Ross. I have plotted my bus against the data in that Cat document and found it to be very accurate. Speed costs! My son works for an oil co and he thinks we are headed for 4-5 dollar a gallon diesel. My brother is paying 3.70 in California now so we are on the way. But California makes better diesel fuel than the rest of the country and it makes it more expensive. Unicorn urine is not readily obtained. So hence the price.

Booyah45828 · 02-17-2021, 09:12 AM

Quote:

Originally Posted by s2mikon

Hello Ross. I have plotted my bus against the data in that Cat document and found it to be very accurate. Speed costs! My son works for an oil co and he thinks we are headed for 4-5 dollar a gallon diesel. My brother is paying 3.70 in California now so we are on the way. But California makes better diesel fuel than the rest of the country and it makes it more expensive. Unicorn urine is not readily obtained. So hence the price.

We're for sure on our way to that. We'll likely pass it to be honest. 4$ gallon gas is in the future, and diesel will be above 5, possibly 6.

s2mikon · 02-17-2021, 09:13 AM

I think that the OP's main concern is down hill control. If I remember correctly he had a bad experience in northern NM coming back from CO. The lack of engine brakes or retarders on some of these buses has to be compensated for when driving them in the mountains. Go slow. If you went up the hill in second come down in second. If you had to go up in first come down in first. And make darn sure that your beneficiaries are not riding in the bus with you.

Booyah45828 · 02-17-2021, 09:52 AM

If more downhill control is needed, or desired. Auxiliary braking is what you're after, whether in the form a driveline retarder or an exhaust brake.

The 2000 will slow the bus down much the same as a manual so long as the shifter is manipulated correctly. If descending a grade, manually downshift it to keep the rpm's up.

thjakits · 02-17-2021, 02:16 PM

Well, if you HAD a 6th (I always thought all 2000s had one, just "not available"...), you could of course lower the differential and gain a closer spacing and lower gears overall - and still have some good cruising speed....
As mentioned - speed costs!!
E.g. in Europe the general speed limit for trucks is 80 kph - 50 mph ..so all trucks are electronically regulated to max 85 kph - 52 mph. Buses are at 100 kph - roughly 60 mph, max 65 mph. Nothing is doing 75 mph!!
Still having mostly the 16-split - max speed rpm is usually anywhere from 1650 to 2000 rpm in the highest gear....
Split across 16 speeds - plenty to find the optimum for any situation....

Now back to your situation - aren't there any splitters that go on the differential itself?��
I think it should be possible to improve right there...
I think these units are not real splitters, but a rather a high/low selection and - possibly - can't be shifted while rolling, but with ratios properly selected you should be able to take full advantage of all 5 gears on a hill!!
Adapting a exhaust break to your engine is not an easy thing!!
Usually there is one or 2 options for any specific engine and configuration - if your engine is not on the list - forget it!! DON'T just try to adapt something because likely you will kill the engine in the process!
If you can get hold of a hydraulic retarder (possibly out of a long range coach) - different story - that would be a great investment!! Beware - with the usual installations - you still need to run the engine at high(er) rpm as the fooling circuit of the retarder is plumbed into the engine cooling circuit and your waterpump takes care of fast enough circulation. Keep it at idle and you overheat in short order!
I'd suggest to forget about the older magnetic retarders - you need to be VERY conscious using these - I saw more than one burned up truck at the bottom of a hill when they used the mag-retarder hard and then had to stop!! ....I think there are now electric recovery systems, using fairly large battery packs (incl . Supercapacitors) - which you then feed back into the drive train - basically a sizable generator/motor between transmission and engine.... (I doubt there is any economically sensible way to get that into a 2005 Skoolie....��)

Another idea would be "Hydraulic Auxiliary drives" used in a number of mainly Construction Trucks.... check out the versions from M.A.N. and Renault - basically license versions of the Poclain Hydraulics Creep drive. That can also be used to store energy and reclaim at will - however usually that drive works to about 40 kph before it disengages - ...might be enough to descend a hill..... and by now available used....

Your best bet is to check out possibilities around the differential, check if a exhaust brake exists for your exact model engine and check for hydraulic retarders for your engine/trans package....

Frankly - with a split unit on the diff and geared to a top speed of 65mph....you should get sufficient downhill breaking in the lower selection....
You are in a Skoolie - what's the rush?!
Settle into cruising at 55mph and you "get there" 10-20min later.... less stress, less money, more relaxed

While you're playing with "diff stuff options" - look up if trucks with the same general axle size might have bigger brakes - rear and front - you might be able to upgrade there!
Also - while you're installing your differential options - check out if you could install a 3rd brake on the diff-input - like 4x4 5-ton axle conversions have....��
You could run that as a seperate circuit and use it as an auxiliary - swap between the wheel brakes and the shaft brake to let the other cool down - install some specific cooling ducts...��

...enough rambled, off the soap box!

thjakits

s2mikon · 02-17-2021, 02:40 PM

I have looked at the possibility of a 2 speed axle for mine and it would give me a 4.1 / 5.7 rear axle combination. It would be perfect as far as I am concerned. It was even an option for the 91 bluebird rear engine bus. If I ever find one I'll more than likely buy it. Right now I'm in the process of installing a MTB 643 that has a retarder. That should give me much better down hill control.

Free Bird · 02-20-2021, 09:32 PM

Quote:

Originally Posted by mrlupr

Will I benefit from converting to manual? If so, what transmission and accessories should I be looking for?

I think Booyah is making a lot of sense, I like his advice.

I converted my bus to manual because it came with a non locking 4 speed auto, if it had come with a 5 spd locker I would never have changed it. The conversion is expensive, requires a donor bus and a lot of foolin around.

I also changed my dif ratio but that was to get me a gear ratio closer to what you already have. If you can do 60 (without lugging) at under 2000 rpm you're golden!

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