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[Derrickl112]

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[jw4x4]

I think they do have lock up during deceleration. That is the reason for the ABS upgrades- to keep from stalling the engine (equals loss of steering). And when mine downshifts, I can really feel it. I am sure someone with more knowledge will chime in here. I kinda like the idea of an exhaust brake.

 

[Derrickl112]

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[quickfarms]

Please look at the model number tag on the side of you trans. I know it is a MT654 but the suffix will tell you if it has a retarder built in it. An Allison dealer or tech support should be able to confirm if this information. I believe that your trans is lockup and probably also has the retarder in it. If it has the retarder you would need to contact both Allison and the exhaust brake manufacturer to se if they are comparable. You can also download the operators manual from the Allison web site.

 

[Derrickl112]

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[markmontana]

searching mt654 on allison's website yields no results.


What about the FMTV's? Do their transmissions have "lock up" in all gears?

Don't search for MT654. It's part of a series of trannies and they use a different title for the info. It's there, I've seen it (and even posted the link somewhere here)

 

[Derrickl112]

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[319]

This help?

 

[markmontana]

That's it!

 

[quickfarms]

I was just about to upload tha manual.

Here is the mechanics tips

 

[Beerslayer]

Oh, they do lock up on deceleration, at least some of them do. I had a terrifying surprise when driving a new to me truck the other day. Came into the freeway exit hot and laid on the brakes pretty heavy. The last downshift or two made a terrible racket and killed the motor. Thought something had blown up.

Scared the **** out of me but nothing was wrong. Just the shift points out of adjustment.

It's a great feature of that transmission, you get engine braking when decelerating, but it does take some getting used to.

 

[quickfarms]

Oh, they do lock up on deceleration, at least some of them do. I had a terrifying surprise when driving a new to me truck the other day. Came into the freeway exit hot and laid on the brakes pretty heavy. The last downshift or two made a terrible racket and killed the motor. Thought something had blown up.

Scared the **** out of me but nothing was wrong. Just the shift points out of adjustment.

It's a great feature of that transmission, you get engine braking when decelerating, but it does take some getting used to.

If I remember correctly the shift point adjustment is internal on the mt series trans and is best set on the bench.

 

[Beerslayer]

The TMs give the shift point adjustment procedure. I didn't want to fool with it and had the Allison dealer do it. Not entirely happy with the results of their work but it is much better.

 

[Bolkbich]

subscribed

 

[quickfarms]

The TMs give the shift point adjustment procedure. I didn't want to fool with it and had the Allison dealer do it. Not entirely happy with the results of their work but it is much better.

What are you not happy about?

 

[Beerslayer]

What are you not happy about?

Not happy with the adjustments made. The truck still upshifts early at a lower RPM that it is supposed to, which is what the dealer was supposed to fix. It will upshift at 16-1700 RPM in some gears when it should shift at 1900.

 

[Derrickl112]

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[quickfarms]

If you read the Allison mech tips you may have to modify the trans to work with an exhaust brake

 

[Truckoholic]

I've got an actual Jacobs engine brake that I took out of an NTC350 cummins that I have been wanting to put in my M925a1, so I have been really curious about this as well!

 

[indy4x4fab]

I know I will more then likely get a butt crewing over this but can an engine brake be put on a m818's NHC 250 with out having a turbo added to it, or put anthere way can a person add a engine bake or jake brake to a na250 cummins?