Allison 2000 transmission? Is it a MT643?

[EastCoastCB]

Originally Posted by BlackHeart

I think you are right.
Using an assumed 245/70/19.5 tire size
and assuming 5th gear is .74 and the rear end is 5.29 - 2000rpm = 50 mph
5th gear being .71 = 52.3
6th gear being .64 = 58.02

There is a 1999 up for sale there that has 4.78 gears.
It looks like this, with the same assumptions:
.74 = 55.5mph
.71 = 57.88 mph
.64 = 64 mph

Looks like if the 5.29 buses were in better shape - I would need to be shopping for some new rear end gears, or hope that the 99 is in great shape - or plan on going really really slow

regearing isn't all that expensive. Less than a set of tires.
A 99 ins't likely to have overdrive unless its got a 3060 in it. Otherwise its 1:1.

[musigenesis]

Originally Posted by Booyah45828

You can do a valve body and tcm swap on a pre 2005 allison 2000 and get 6th gear that way. Changing the valve body only requires a pan drop, it doesn't require transmission removal.

Is this true for any transmission? I have a 2000-series (don't know any more than that) with 6.17 gearing and it maxes out at 65 mph and 2600 rpm. My shifter doesn't have a circled D and 4 is the highest gear on it - can I get extra gears and how much does a valve body and tcm swap cost?

[Native]

Originally Posted by musigenesis

Is this true for any transmission? I have a 2000-series (don't know any more than that) with 6.17 gearing and it maxes out at 65 mph and 2600 rpm. My shifter doesn't have a circled D and 4 is the highest gear on it - can I get extra gears and how much does a valve body and tcm swap cost?

You can use the gear calculators to determine your top gear ratio. I am thinking you have an AT2000 with a 0.74 overdrive. I say this because your numbers follow mine pretty much (that is if I had a 6.17 rear gear instead of the 5.57 I have). I run about 72 MPH at 2500 RPM in overdrive (0.74:1 ratio).

[EastCoastCB]

Originally Posted by musigenesis

Is this true for any transmission? I have a 2000-series (don't know any more than that) with 6.17 gearing and it maxes out at 65 mph and 2600 rpm. My shifter doesn't have a circled D and 4 is the highest gear on it - can I get extra gears and how much does a valve body and tcm swap cost?

You'd be much better served getting more rv-appropriate rear gearing. You've got overdrive already. another .10 of OD isn't going to do nearly as much as gears.

[cadillackid]

to upgrade a 5 speed from 5 to 6 you need a valve body swap which adds some new solenoids and a new internal harness.. you'll need a complete new trans wiring harness as the 4th gen TCMs that support 6th gear are a single 80 pin connector vs the 2 or 3 connector models (3rd gen).. while the 3rd gen TCM is capable of 6 gear control.. no CINs were ever created for it that are designed for the 1000/2000.. while its theoretically possible to take an MD3060 TCM, reload its OS with a base load capable of being tuned via EFIlive and then building up a program from scratch using the base TAPs from an existing 1000/2000, then build a shift table with 6th gear, you'd likely have issues with it..



the cutoff year is somewhere around mid 05 as booyah mentioned.. for all intents and purposes its model year 2006 and up since school busses were built quite a bit ahead..



the retrofit isnt for the faint of heart when it comes to electronics or even mechanics.. while dropping and replacing an allison valve body and internal wire harness are fairly straight forward, you'll also need to replace the external one and wire it into the bus so all functions operate..



-Christopher

[Booyah45828]

Originally Posted by EastCoastCB

regearing isn't all that expensive. Less than a set of tires.
A 99 ins't likely to have overdrive unless its got a 3060 in it. Otherwise its 1:1.

No it's not expensive, but it depends on if you can find a good used 3rd member.

But, If you need new tires.....

and those low pro 19.5's ride like a log wagon as is.

[Booyah45828]

Originally Posted by musigenesis

Is this true for any transmission? I have a 2000-series (don't know any more than that) with 6.17 gearing and it maxes out at 65 mph and 2600 rpm. My shifter doesn't have a circled D and 4 is the highest gear on it - can I get extra gears and how much does a valve body and tcm swap cost?

Yes, on all 1000+2000 transmissions the gearing is there already internally.

Like christopher alluded to, you'll need to run more wires for the swap, but that to me is easy compared to changing over the valve body.

Sourcing the parts to do so might be the difficult task.

You're sure you have a 2000 series?

Every 2000 series I've looked at has a circled D, a D, then 2, then 1.

OR

Some had a D, then 4, then 2 and 1.

If you shifter has a D,3,2,1 it might be an at545 or mt643

[musigenesis]

Originally Posted by Booyah45828

Yes, on all 1000+2000 transmissions the gearing is there already internally.

Like christopher alluded to, you'll need to run more wires for the swap, but that to me is easy compared to changing over the valve body.

Sourcing the parts to do so might be the difficult task.

You're sure you have a 2000 series?

Every 2000 series I've looked at has a circled D, a D, then 2, then 1.

OR

Some had a D, then 4, then 2 and 1.

If you shifter has a D,3,2,1 it might be an at545 or mt643

It's definitely a 2000-series, or as my mechanic put it: a 7000-series (it's a bit dirty). I'm pretty sure it's D-4-2-1 but I'll have to look again to make sure.

[Booyah45828]

I mean, a shifter is just a shifter. So they could have swapped an older shifter into a newer bus. It's just strange and would be something I definitely would investigate.

[musigenesis]

Thanks all, you've reminded me again of why I'm never going to unlock 6th or change the gearing (at least not until way in the future). I don't drive it enough to justify the expense and effort and I'm pretty content chugging along at 60 on the highway. There are actually some really steep hills around where I live (actually ridges and valleys, part of the Delaware's catch basin) between my house and my lot which I think the 6.17 helps with - bus has no trouble getting up these. If unlocking 6th were just a software change I would certainly do it.

[cadillackid]

I would ditch that 6.17.. 2600 RPM and 6.17 gears. with .74 overdrive.. you are really piushing the output shaft speed to the max. . just seems noisy to me and unless that driveshaft is perfectly balanced.. U-jopint life will be shortened.. nopt to mention crappy MPGs running that engine at redline RPM.. it wont hurt the engine.. they are designed for it.. to me it would be well worth dropping a 5.29 or such rear end in it. and then dropping out of OD into 4th to climb the hills


a bus that new.. these lots of compatible rear end 3rd members in junkyards out there.. other than weighing a couple hundred pounds, a 3rd member swap is easy.. you dont even have to take the wheels off....

[EastCoastCB]

Originally Posted by Booyah45828

No it's not expensive, but it depends on if you can find a good used 3rd member.

But, If you need new tires.....

and those low pro 19.5's ride like a log wagon as is.

There are tons of good used takeouts on vanderhag's and lkq.
But yeah I'd skip a lowrider on 19.5's.

If I were MusicGenesis I'd be hunting for a 4.78 or 5.29 set.

[Chaos0812]

Guys, all of this is just a dream to me. I'm still running a AT545,......with 6:18 gears! I have to redline my 7.3 to get 62mph. I gotta do something before I scatter IHC guts all over the highway.

[Sir Campbulance]

Do you guy think I can get the 6th gear out of the 2200ev transmission with a tcm flash? If so what would i need to do to get it flashed could I send the tcm out or buy one ready?

[cadillackid]

what year is the bus? 2006+ using the single-conector (gen 4) TCM are when the 6 speed valve bodies were in the 2000 series

[Sir Campbulance]

06 this is the s/n 6310671190 it was an ambulance

[57gmc cummins]

I have a 2002 allison 2000 paired with a cummins 24 valve out of a bluebird school bus the wiring is a little cut up and not sure if it will work. i know they make manual valve bodys for allison 1000 do you know if they make them for thr 2000 or is the 1000 valve body would work? thanks!

[Soaringcook]

Can a mt643 be swapped for a newer allison model and if so what model would be easiest to install?