T444e 643 swap unobtainable ring part number

[Trav5122002]

Originally Posted by cadillackid

When you machine it down did you make sure there was a properly sized pilot the converter nose must be in a pilot that is not press on tight but is a snug fit to keep it true … also how much clearance did you have from converter fully back to pushed against the flexplate

The hub fit onto the pilot snug but not tight and I had 2.5” of clearance, the trans went on with no problems how much clearance should I have ? So did I destroy my transmission? What did I break ?

[Jolly Roger bus 223]

your machine shop should be the ones to answer that for you.
an auto parts store is only going to give you OEM stuff.
you had things changed?
now its up to you to figure it out.
what changed between the rear main seal and front tranny pump seal?
puking tranny fluid sounds like a front pump seal to me.
thats an opinion?
you have to make your own.

[Trav5122002]

I pulled the transmission and replaced the seal and had the hub adapter cut down another 1/4” and bolted everything back together and crossed my fingers … so far everything is great!! No leaks and truck drives well and the bed dumps good as well I think I’m gonna have the dealer reprogram the computer for the 210hp option right now im at 190hp but so far so good ! Thank you everyone for the help !!

[Booyah45828]

That doesn't make sense to me, but hey if it works, whatever.

For anyone else reading/doing this, there is a converter protrusion spec that you follow, and putting the converter in that range is what this spacer is trying to achieve. Too little of a spacer and the converter hangs out the front, too much and the converter hub will be pushed into the pump too far, ruining things internally.

So measure, and measure, and measure again in order to get this right.

[Trav5122002]

The transmission works great but it seems it will not downshift I had another modulator and put it on and got do difference and with the key on and the pedal to the foor I’m receiving 12V at the modulator plug…. Any ideas what I should look for next ? 1999 T444E international 4700

[Booyah45828]

Did you check for a ground the plug?

With the modulator plugged in, but removed from the trans, do your key on pedal floored routine and see if the plunger kicks out. Modulators failed often, so it's not out of the question that both you have are junk.

[Trav5122002]

Originally Posted by Booyah45828

Did you check for a ground the plug?

With the modulator plugged in, but removed from the trans, do your key on pedal floored routine and see if the plunger kicks out. Modulators failed often, so it's not out of the question that both you have are junk.

No I’ll check for a ground now , with my key on and when I press the pedal I can hear a slight clunk but when I hook positive and ground up the the modulator it’s a more noticeable clunk could that mean anything ? UPDATE I checked for ground with a voltmeter and from the negative wire on the plug and went to the positive on the battery I have 12.33 volts

[Booyah45828]

Well, I guess define what you mean by downshift. Like it's stuck in 4th all the time or it won't kickdown when floored at 35? If it's stuck in 4th all the time I'd make sure the shifter is adjusted correctly. If you have no kickdown, and you're sure the modulator is working, lack of a kick down could be caused by internal valve body issues.

[Trav5122002]

Originally Posted by Booyah45828

Well, I guess define what you mean by downshift. Like it's stuck in 4th all the time or it won't kickdown when floored at 35? If it's stuck in 4th all the time I'd make sure the shifter is adjusted correctly. If you have no kickdown, and you're sure the modulator is working, lack of a kick down could be caused by internal valve body issues.

It’ has no kick down when you floor it at 35… maybe both my modulators are bad I’m not sure now

[cadillackid]

every transmission has a shift schedule in it that is its base.. MPH really doesnt mean a lot.. if you put your foot to the floor does it upshift at close to its rated RPM? ie if the trans is set for 2600 RPM is it shifting out under full throttle from 1-2, 2-3,3-4 at close to 2500 or so?


if its always upshifting to top gear at low RPM or feels like it is shifting way too early all the time then it can be modulator issue.. a 2600 RPM MT643 under full throttle should shift to 2nd at something close to 2500 engine RPM.. 3rd the same way... then lockup comes on halfway through 3rd and you know it when it hits.. the whole truck pops forward and RPM gives a pronounced drop.. it feels like a shift.. then 3-4 shifts at 2400-2500 RPM.. those are full thrott;le (modulator on) shifts..


you wont be able to downshift from those shifts unless you move the T handle and even then it may not want to drop unless you have lost some speed..


now unmodulated or part throttle shifts should be earlier than full throttle.. at light throttle a 643 may upshift at as early as 1600-1800 RPM.. lockup turns on Very early into 3rd gear and 4th gear is extremely early.. those kind of shifts if you punched it directly after a light throttle shift you can often get a downshift back down from a light throttle (unmodulated) shift..


every transmission has a deadband so that it tries to prevent hunting (up-down-up-down) in quick succession.. so in my 643 if I punch it and it shifts out at 2500 ROM into 4th.. and I lose speed on the highway on a hill.. my engine RPM has to drop to about 2000 RPM before it will downshift into 3rd.. i can manually drop it with the T handle if I need the downshift now.. otherwise it wont.. and thats expected as the RPM rise you get from the downshift is designed not to cause an immediate upshift.. so you dont want it to downshift right back to its max and then upshift right away.. so it means you may feel like you are lugging down a bit in that higher gear.



electronic transmissions like the 2000/3000 can protect against hunt shifts by the computer recognizing it.. mechanical transmissions like an MT643 or AT545 didnt have that luxury the valve body could buffer hunting a bit but the usual way seemed to be wider deadbands than modern electronic units have...

[Booyah45828]

Correct.

When I said 35 mph, that's the figure we used testing them. It's kind of a approximate speed, doing 36 doesn't necessarily mean it won't work, or doing 34 too. The reason we chose 35 was because most buses that used mechanical transmissions were geared to run against the governor at around 55 or so in 4th, as 55 was the federal speed limit before 1995.

35 mph would put you below your dead zone you talk about, in that no-load you'd be in 4th, but fully loaded would downshift you into 3rd. If you were doing 40 or 45, that might put you in the deadzone where it won't kickdown. Change the gearing, tire size, or governor in the trans and those mph numbers go out the window.

There was a few year window in there after 95 and buses still used a mechanical transmission, that can change the mph the bus can run. And those few years might have a different testing speed.

Morale of the story is to go fast enough to get the trans into 4th at no-load and a low(lugging) rpm. Then floor it, you should get a downshift. Your governor should have an rpm rating, and if the rating is off compared to your engine's governed rpm, it will cause the shifts to be incorrect as well.

[cadillackid]

in layter years there were really only 2 governers used.. a "gas" and a "diesel".. shift points could be trimmed up or down a couple hundred RPM either way by adjusting the trim wheels on the valve body.. what I dont know is if allison used a bunch of different governer gears like GMC did on their 350's .. ive only ever seen a gray and an orangish governer gear on a 643 or 545 ..


adjusting the trim wheels inside the transmission is a bit tricky as they adjust the Tailshaft RPM.. in lower gears you get more engine RPM effect per "click" then you do for the higher gears due to the ratios raising as you go through the gears..


its entirely possible that that particular transmission is "trimmed" for a different engine.. for instance my 643 was technically made for a DT466 so it never shifts above 2500-2600 RPM. my DTA360 can run up to 2700-2800 so if I wanted to run-out my gears a little further i could trim it higher by pulling the pan down and adjusting the trim wheels..


the OP could have a trans trimmed for a bigger engine like a cummins 8.3 that only max revs to 2400 so all the shifts feel early and "luggy"..



another thing about trim and transmission age.. springs do lose tension over the years.. so if the trans is physically old its possible the valve body springs have lost a little tension which has the effect of lowering shift-points slightly over time...

[Trav5122002]

Okay, that makes sense now, after installing a new modulator and cleaing the plug connection I do have kick down now and also my shifts seem to be normal or comfortable and don’t seem early anymore but one more thing I’ve noticed is when the transmission downshifts it almost seems like it goes in neutral and it takes 5- to 8 seconds for 1st gear to engage ….. when your I traffic going from red light to red light stop and go i bought The transmission used and was told it was rebuilt by weller 30,000 miles ago…. Could be very true because it does have a weller tag on it but honestly who knows

[cadillackid]

wow! so when you stop at a light and go to take off its like 5 seconds of engine revs and bus goes nowhere?

[Trav5122002]

Yes, if your sitting at the light for a little it’ll take off fine but if you just stopped and then Tried to take off right away from a stop it takes 5 or so second’s to engage…. I’m honestly worried…. What could that be ? Dirty filter ? Valve body adjustment? Or?… Transmission shifts nice and smooth other then that I’ve checked the fluid multiple times and it says it’s full when idling in neutral up to temperature the truck is a 1999 4700 T444e dump truck with a pto bolted on the transmission

[cadillackid]

low fluid? drops into neutral from the surge forward stopping then pickup grabs fluid after it levels in the pan? you want to check the fluid with the bus running and the trans warmed up..

[Trav5122002]

Originally Posted by cadillackid

low fluid? drops into neutral from the surge forward stopping then pickup grabs fluid after it levels in the pan? you want to check the fluid with the bus running and the trans warmed up..

Alright I’ll check it again on level ground maybe the truck isn’t level when I’m checking it when it’s running. I’ve added just about 5 gallons so far … I do have a pto on it with external pressure hoses, one tees off one of the cooler lines and I have the other on the main pressure port of the transmission so maybe it’s gonna take a little more