allison auto - Page 2 - Diesel Forum

Garbage_Mechanic · 11-09-2007, 07:44 PM

I know what you are going through in that 4700 with the AT545. Feels like a rubber band is connecting the wheels to the engine in 4th huh? RPM stays at governd speed above 40 mph, and the vehicle speed finally catches up to the engine RPM. Have much problem with it running hot? I solved all of them on mine with an MT643.

There is a lockup 545, i don't know the model # I will try to find out. It was only made for a year or two.

spg · 11-10-2007, 10:59 AM

I would appreciate whatever info you can provide. Looking to improve mileage. Mostly highway use while towing a 28' trailer at about 12k. Truck has a 24' box.

What does it take to convert to a MT643? First choice would probably be a lockup 545. Or I have considered changing it to a handshaker.

Thanks Steve

Birken Vogt · 11-10-2007, 09:18 PM

My opinion is to put a 10 or 13 speed in it and be done with it. I don't hate automatics but for highway use and avoiding all the calibration hassles and possible expensive failures that an automatic can bring, plus the continued fuel economy penalty even with a lockup converter, I would put a manual in it.

Birken

navistar45 · 11-26-2007, 11:09 AM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TheBlueMule</div><div class="ubbcode-body">Just got the truck back home and the transmission is broken in about 4 pieces around the case. The tag says it is a MT643. That is probably what I will end up replaceing it with. I was wondering about the MT 650/653 though and are they realy a true 5 speed? garbage_mechanic said it has a granny gear rather than an OD. Is this tranny a better decision over the MT 643? I already need a new drive shaft so I can get it shortend when I'm getting a new one.

Thanks </div></div> i feel ashamed, and should have known better. the 545 was only behind the non turbo 3208. and only then in earlier years, my bad..

ThomasBrooks · 12-17-2007, 12:52 AM

Well we bought a rebuilt MT-643 with torque converter for "Big Red" Thanks for your help to find out what the heck it was. I'm sure I'll be posting questions if anything doesn't go right. [img]/forums/images/%%GRAEMLIN_URL%%/wink.gif[/img] I'll post when it is up and going. THANKS AGAIN!!

TheBlueMule

wawrd1 · 07-08-2008, 11:19 AM

While all you guys are at it, I'm looking at a truck with a MT 650. Can any one give me any insite into this tranny?

castirondude · 10-25-2009, 10:29 PM

I'm trying to mate a MT643 to a Deutz engine SAE #1 bellhousing with SAE 11.5 flywheel. Is there something available from Allison to do this? If these transmissions were used behind a cummins 855, those have SAE #1 bellhousings, right? I wonder if these transmissiona had different housings or used an adapter.