mt654cr transmission shifting charateristics and tendencies discussion

[quickfarms]

Quckfarms, what is the correct way to drive an Allison? I've read the Allison manual other than selecting the proper gear for the conditions they don't say much more about it. Am I missing something and can you give me some insight to the Allison transmission in a M923A2.
thanks, Bryan

The first thing to remember is that you are driving a truck and not a sports car.

The best way to describe it is that once the vehicle had reached operating temperature you accelerate at full throttle until you reach your desired speed. If you are not at full throttle the transmission can and will typically short shift, I purposely take it an easy until the vehicle is up to operating temperature.

When driving you need to watch the traffic as far as you can see in addition to the brake lights in front of you. This is an effort to avoid or eliminate panic stops.

I was thought to downshift to a stop. You can have the Allison do this. You need to plan ahead and leave room for the vehicle to slow down. I have found that it works best to taps the brakes to begging the deceleration and the Allison will compression brake to a very low speed and the final stop may just require a slight application of the brakes.

I hope this helps.

Let me know if you have any questions.

 

[lindsey97]

The first thing to remember is that you are driving a truck and not a sports car.

The best way to describe it is that once the vehicle had reached operating temperature you accelerate at full throttle until you reach your desired speed. If you are not at full throttle the transmission can and will typically short shift, I purposely take it an easy until the vehicle is up to operating temperature.

When driving you need to watch the traffic as far as you can see in addition to the brake lights in front of you. This is an effort to avoid or eliminate panic stops.

I was thought to downshift to a stop. You can have the Allison do this. You need to plan ahead and leave room for the vehicle to slow down. I have found that it works best to taps the brakes to begging the deceleration and the Allison will compression brake to a very low speed and the final stop may just require a slight application of the brakes.

I hope this helps.

Let me know if you have any questions.

Mine downshifts and compression brakes exactly as you described quickfarms. Maintaining proper stopping distance is crucial in these trucks, and it depends on the weather and traffic conditions also. I have a class a cdl and own 2 dump trucks, and am very familiar with the use of compression braking.

my truck upshifts a lot better now that I have adjusted the cable 4 turns. guess I was being paranoid about it.

 

[tashaak]

I hope you can help me you sound knowledgeable on the mt654cr transmission. I am having an issue on overfilling my transmission. I just dropped the pan and changed the internal filter and put in Dextron 3 and also changed the external filter. I got it up to operating temperature and all the lines from the cooler are warm and purged it through the petcock valve by the cooler and it is red showing it is flowing through. Then when I check the level it comes out the fill tube. My vent line is clear to the intake stack and I blew into the trans and it is clear into the trans. I think I have the wrong dip stick it may have been replaced by the previous owner I think. So I think I may be overfilling it. I have seen the Allison transmission mt(b)600 series mechanics tips book. I look at those dip sticks and mine is nothing like any of them. I guess my question is is where on the oil pan should the level be? From what I can figure with the 5 inch pan I have the hot run level should be at 3/4 '' to 1.5'' from the flange line,is that accurate. If you have the same trans with the 5 inch pan is it possible you can measure you dip stick and give me overall length of the dip stick and where the measurements of the hot and cold lines are. Also if there are 3 different oil pan depths is the amount of fluid the same in all three. I would think they would be different. According to the TM it is 4.25 gallons(17qts). Is it possible I am also putting in too much for the 5 inch pan. Thanks Gary

 

[Jason O]

Dipstick length top cover to bottom: 17"

Cold full mark to bottom 2 1/4"

Add mark to bottom: 3 1/2"

Full mark to bottom: 4 1/2"

This is for one of my A2 trucks with the 6cta

 

[Jason O]

Tashaak-

To clairify, the length above does NOT include the Tee handle.
Sorry, didn't get you a photo (phone trouble).

 

[Tow4]

When the transmission is cold it will read low. If your dip stick doesn't have a cold fill mark be aware of that. The level comes up as the fluid gets hot.

 

[Artisan]

Precision Allison Transmission

These guys are top notch, old school, they have a dyno.
They receive trannys from across the country for rebuild
almost daily plus all the local schools and garbage and
even Police big rigs. T

Tell them the Dave CAT 7155 guy sent you. Yes, I
brought them a new 7155 in a crate and they stuffed it
for me for a song and a dance and while I was there
I became absolutely SOLD on there work. The shop
is clean and no screwin' around. HUGE rigs all over the
place getting reset trannys stuffed and pulled and
rebuild and boxed and sent out. I did a video on
You Tube of the owner manning the dyno...HERE

 

[tashaak]

I have a cold reading which is about 3/4'' from the flange. My dipstick is 21 '' long not 17 as Jason mentioned. Is the correct reading 3/4'' from the flange no matter what dipstick I have. Also I am trying to blow through the vent into the trans and I am getting back pressure. Is that because I am trying to push fluid. Is there a way to tell if the vent is plugged in the trans. It is clear from the vent to the stack. Is it okay if I give you my phone number so we can talk.

 

[Tow4]

The dip sticks are different lengths depending on oil pan depth. I posted a couple of Allison TMs in the TM forum here, one of them gives info on fluid levels based on pan depth.

 

[spicergear]

Deleted. Starting new thread.

 

[CARMAN]

Another good read.