T444E safe operating RPMs at highway speeds

[steveningham]

How many RPMs can I safely run with a T444E on a freeway? My 35' 2000 International RE with a T444E is running around 2500 RPMs at 58 to 60 MPH. What are the safe RPMs for the T444E ? How many RMPs are these engines designed to run at highways speeds? I would like to be able to cruise between 65 and 70 on the freeway. Do I need to have the rear end ratios changed? Or can the T444E handle 3000 RPMs at freeway speeds?

[cowlitzcoach]

2500-2600 RPM's is about as tight as I would want to turn one of those on a regular basis.

3000 RPM's is really asking for trouble IMHO.

[cadillackid]

ther T-444E should be limited to 2700 from the factory... maybe the 210 HP version is 3000? I do know they max out their power and torque curve at 2300.. which is a good optimal balance of economy and power there...

the bottom end on these things can take more.. ford ran them up to 3200, but the fords i believe have a slightly thicker head gasket than the IHC so you can run higher RPM wothout slapping a piston at the top of the cylinder.

even with 210 HP, i cant imagine being able to have enough power to run a big heavy RE bus at 65-70 with a T-444E..

when you regear you also lose torque at the tires... a good test is does your bus want to slow down any on mild hills? if you are floored and drop speed a little now on hills you would drop speed even more if you re-geared the rear...

-Christopher

[Dana]

My 95 Int. T444e with the AT545 trans (4 speed) is limited to 2600 RPMs and runs down the highway at 65MPH. As far as I know it should not hurt the engine to run 2600 all day. The t444e (the 175 hp version) HP peaks around 2200 RPMs and the torque (460) around 1400. So the engine "lives" in that range.

International T444E Specs & Info

One thing that I found interesting when I started driving trucks for a living was most truck (I drove) would be flat out, 100% throttle on the highway. You just stand on it and let the truck run where she likes.

I live in Florida so its flat roads except for bridges. I find the bus keeps speed (65) over most large bridges. On the downhill side the RPMs will actually come down a tick as the bus passes 65MPH.

As long as your water temps are within normal range (mine runs about 206) and oil pressure is good, running 65 all day at 2600 RPMs should be fine for the engine.

These buses are just not made for highways. So they seem a bit uncomfortable on them. Mine likes to cruise at 50 MPH. At that speed it is turning about 2100 RPMs.

I am thinking of adding a Gear Vendors over-drive unit. It would have be a Divorced unit, meaning it would replace a carrier bearing in the driveshaft. Then the bus should run at 70MPH and turn about 2100 RPMs. I don't think I want to go much faster than 70mph.

But the over-drive unit is $3100 and then it would need to be mounted and the driveshafts would need to be shortened. I estimate the whole thing would be about $4500 and I only paid $2300 for the bus.

But then again I did just drop $2700 on 6 new tires. Seems like the parts are more expensive than the whole.

[cadillackid]

Originally Posted by Dana

My 95 Int. T444e with the AT545 trans (4 speed) is limited to 2600 RPMs and runs down the highway at 65MPH. As far as I know it should not hurt the engine to run 2600 all day. The t444e (the 175 hp version) HP peaks around 2200 RPMs and the torque (460) around 1400. So the engine "lives" in that range.

International T444E Specs & Info

One thing that I found interesting when I started driving trucks for a living was most truck (I drove) would be flat out, 100% throttle on the highway. You just stand on it and let the truck run where she likes.

I live in Florida so its flat roads except for bridges. I find the bus keeps speed (65) over most large bridges. On the downhill side the RPMs will actually come down a tick as the bus passes 65MPH.

As long as your water temps are within normal range (mine runs about 206) and oil pressure is good, running 65 all day at 2600 RPMs should be fine for the engine.

These buses are just not made for highways. So they seem a bit uncomfortable on them. Mine likes to cruise at 50 MPH. At that speed it is turning about 2100 RPMs.

I am thinking of adding a Gear Vendors over-drive unit. It would have be a Divorced unit, meaning it would replace a carrier bearing in the driveshaft. Then the bus should run at 70MPH and turn about 2100 RPMs. I don't think I want to go much faster than 70mph.

But the over-drive unit is $3100 and then it would need to be mounted and the driveshafts would need to be shortened. I estimate the whole thing would be about $4500 and I only paid $2300 for the bus.

But then again I did just drop $2700 on 6 new tires. Seems like the parts are more expensive than the whole.

so far i have put about 4000 miles on my 444E running it over the highway..

your 444E is probably computer speed-limited at 65 so thats why your RPMs drop going down hill as the vehicle speed limiter lowers throttle input..

if I was going to make an upgrade for that kind of money I would likely upgrade to an allison 1000 / 2000 transmission before id re-engineer a gear overdrive unit...

ive been researching such an upgrade both with a new / reman transmission and with a used transmission..

-Christopher

[steveningham]

This is great info. Is the Alison 1000 2000 an over drive trans? Wouldn't it be less expensive to just change out the pumpkin/ rear end to a better gear ratio ?

[steveningham]

Originally Posted by Dana

My 95 Int. T444e with the AT545 trans (4 speed) is limited to 2600 RPMs and runs down the highway at 65MPH. As far as I know it should not hurt the engine to run 2600 all day. The t444e (the 175 hp version) HP peaks around 2200 RPMs and the torque (460) around 1400. So the engine "lives" in that range.

International T444E Specs & Info

One thing that I found interesting when I started driving trucks for a living was most truck (I drove) would be flat out, 100% throttle on the highway. You just stand on it and let the truck run where she likes.

I live in Florida so its flat roads except for bridges. I find the bus keeps speed (65) over most large bridges. On the downhill side the RPMs will actually come down a tick as the bus passes 65MPH.

As long as your water temps are within normal range (mine runs about 206) and oil pressure is good, running 65 all day at 2600 RPMs should be fine for the engine.

These buses are just not made for highways. So they seem a bit uncomfortable on them. Mine likes to cruise at 50 MPH. At that speed it is turning about 2100 RPMs.

I am thinking of adding a Gear Vendors over-drive unit. It would have be a Divorced unit, meaning it would replace a carrier bearing in the driveshaft. Then the bus should run at 70MPH and turn about 2100 RPMs. I don't think I want to go much faster than 70mph.

But the over-drive unit is $3100 and then it would need to be mounted and the driveshafts would need to be shortened. I estimate the whole thing would be about $4500 and I only paid $2300 for the bus.

But then again I did just drop $2700 on 6 new tires. Seems like the parts are more expensive than the whole.

Thanks for the info. I thought about a gear venders over drive also. What about just changing out the pumpkin/ rear end drop out, for on with a better ratio ? Wonder what that would cost?

[cadillackid]

if you can get lucky enough to find a rear gear set on a used bus that will fit, then yeah on most its a pretty easy swap to pull the 3rd member and swap it into another assuming the housings are the same... but if you have to buy a bunch of parts and then set up the carrier and all it gets a lot pricier and tougher t odo.. though not impossible with standard air tools by any means...

I was only looking at it from an aspect of using a separate overdrive gear... I myself would drop in the OD transmission and have its computer programmed to my Spec... but im also starting with an AT545 which if a taller gear is put on that you'll end up over-temp the transmission much easier as you slig the torque converter... and on a 545 too low of RPM's you'll run low line pressure and slip the clutches esp in 4th gear.. with an MT-643 those issues womnt occur as it has lockup and runs higher line pressures at lower RPMs.
-Christopher

[steveningham]

Well, then the MT-643 sounds like the way to go if the cost is reasonable. Would it work with the current 4 speed shift handle/set up that is on the dash of the bus? Or would that need to be changed? Is the drive shaft on the RE bus the same for both trans? Is is a drop in or would there be other stuff to change out as well? Wondering what the cost is for a good used or rebuilt MT-643? Any trade in value for the good 545?

[EastCoastCB]

I'd look for a good used 643. The driveshaft will need to be shortened some, and I'm not sure what bell housing the 444E has. You may need a bell housing adapter, too. If you're gona do this upgrade I'd look for a 643 with a retarder. Would be two huge upgrades in one! I've seen them for as little as $600. $750 all day.

[cowlitzcoach]

If you are lucky you might find a good used MT643 in a wrecking yard for a reasonable price.

It will most likely require a different driveshaft as it is longer than an AT540.

It will most likely use the same mounts.

The cooler and cooler lines will need to be flushed.

It would be smart to get a new/reconditioned torque convertor and replace the flex plate. No matter how nice the flex plate looks you don't ever want to put a new torque convertor onto an old flex plate. More times than not changing stuff on the flex plate will cause stress cracks that will eventually take out the torque convertor or cause the flex plate to separate at the hub.

You should be able to use the same Morse control for either transmission as long as the cable is long enough to reach and shift into all positions.

Prices for MT643:

• Reman'ed will run around $2,200.00 plus a rebuildable core.
• Used inspected pullouts around $1,300.00 plus a rebuildable core.

Prices for MD3060:

• Reman'ed will run around $5,600.00 plus a rebuildable core
• Rebuilt will run around $4,100.00 plus a rebuildable core
• Used inspected pullouts around $2,300.00 plus a rebuildable core

Your problem is you will have to just about double those costs if you don't have a qualifying rebuildable core. It almost becomes less expensive to purchase outright a brand new MD3060 that will work with your engine.

One thing to consider, after about model year 1999 the engine computer talks with the transmission. Some of the transmissions in 1999 and 2000 were still mechanically controlled. For those buses swapping out transmissions is not a big deal. But on newer electronically controlled engines and transmissions you can't just swap things around.

The new electronics are not only proprietary but the OEM's guard their secrets very jealously. If it very possible that an engine or transmission that was taken out of a different vehicle from a different model year, even though all of the parameters are the same (torque, HP, RPM's, etc) there is no guarantee that the electronics will allow either one to talk to each other.

I have seen it happen more than once where an operator tried to get by on the cheap with a pull out from a wrecking yard only to discover the two parts won't talk together and the rig won't run.

I suppose what I am saying is it isn't like working on a Tri-5 Chevy where parts interchange and you can do all sorts of wild and crazy stuff and they will all run at the end of the day. When you throw modern engine and transmission electronics into the mix you may end up with a multi-thousand $$$$ piece of yard art.

Good luck!

[EastCoastCB]

ALLISON MT 643 TRANSMISSION ASSEMBLY LOW MILEAGE TAKEOUT | eBay

1989 Allison MT643 Transmission 60,000 Miles | eBay

Allison Transmission Model MT643 - Remanufactured | eBay

[Kubla]

another thing about the MT643, they came with 3 different torque converters, not sure how to tell and what the differences actually are, found out after i bought the one I have (not installed)

[cadillackid]

What EC said, I honestly can't remember if the 444E is sae 2 or 3, the bell itself is the same it just whether you need a bolt pattern ring adapter. Driveshaft shortening is a routine thing for a machine shop. I use to have it done reasonably all the time. The shifter is the same on all of them other than the number plate,

All my knowledge is FE / CR so I'm not sure on RE what's what.
If you go the route of a 643 then you don't Gagarin any fearing advantage over a 545 but you gain the locking converter .

If you go overdrive like a 1000/2000 you gain overdrive. Used 1000/2000 are out there but you need the computers to make them run.

When I looked at a full turnkey 1000 kit with all computers, reman trans, etc for my 444Ecit runs about 6-7k.
Getting a used 2000 is possible but you'll need the full engine harness and computers as well the as trans and it's computers.. my retrofit runs the trans standalone, a used set talks to the engine computer
Christopher

[steveningham]

The increased freeway cruising speed on flat highway would make long distance traveling much better if the engine has the power to maintain the speed. Steady cruising at 65 to 68 is just about right. I expect, keeping the weight of the bus low, and the wind resistance as low as possible would also help. Think I'll wait and see how the conversion goes. If I'm happy with it, $6 to $7 thousand would be well worth spending on the drive line. Thanks for the info.

[Dana]

The more I have looked into this issue the more I like the idea of changing to a 5-speed Spicer ES43-5A transmission. Swapping out the AT545 for any other automatic transmission means dealing with compatibility issues with the electronics and torque converters.

For my 1995 International they sold my 175HP T444e with the ES43-5A trans. The 5-Speed should give me a little better highway speeds and the added benefit of more control over downhill speeds. I have found these transmissions on eBay for around $2000 so it is a cheaper option than a Gear Vendors over-drive.

A bell-housing and a clutch is going to be far cheaper than a torque converter. There is no need for a transmission cooler (unless you really want one). A standard just makes things much simpler.

Driving a "school bus" with a standard would be a pain, but as an RV I think it would be a better option. I use to drive a 20' box truck (Volvo) delivering plumbing & heating supplies and it had a 5-speed. It was great, like driving a BIG pickup.

[cadillackid]

I think a standard in an over-the-road RV is a great way to go.. esp for someone like yourself that already knows how to drive a medium duty standard truck..

if your plans have you ending up in city traffic passing through various places or lots of in-town i probably wouldnt want a standard.. but out on the road you cant beat it... in the mountains you can pick a gear and stay there rather than the continuous up and downshift of an automatic...
-Christopher

[Spartan]

Mine will cruise at 63mph and the sounds goes way down and sort of settles in there. (2200 RPM)
It will go up to 70mph at around 2400

[cadillackid]

Originally Posted by Spartan

Mine will cruise at 63mph and the sounds goes way down and sort of settles in there. (2200 RPM)
It will go up to 70mph at around 2400

what do you have? a standard? and a 444E?
-Christopher

[steveningham]

My bus is a 2000 model RE, so I don't know that it would be possible to put a standard shift in my bus. I don't mind a standard though.