Torque Converter Aggressive in Reverse

[Isawfrizzy]

So this is my first 5 ton truck (M923A2) and have no other experience driving one. The one thing that doesn't seem right is when I shift into reverse it really wants to go. When I'm backing it into the spot I keep it I really have to be on the brakes and then when I shift it into neutral there's a noticeable unloading, almost like I was trying to do a brake stand. The RPM's are down at around 700-800 but it seems like the torque converter is really aggressive. Going in forward gears it seems normal where I have to press the accelerator to move forward otherwise it will just idle and not move and going down the road it shift and goes really nice.
Is this normal or is there something out of adjustment or not working correctly?

 

[Rmtaunton]

Reverse is geared much much lower than 1 st I think it's 9 to 1


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[Jbulach]

You need to find out why your idle is so high, I'm surprised your brakes even hold in reverse at those RPM.

 

[Tinstar]

Idle is a bit too high and add the very low reverse gearing and it will do what your describing.

 

[Isawfrizzy]

Idle is a bit too high and add the very low reverse gearing and it will do what your describing.

What is the ideal idle speed? Why does the torque converter act differently in reverse than forward gears?

 

[Tinstar]

It's not the torque converter acting any different.
Like mentioned above, it's the reverse gearing.
Its very low. I do not recall the ratio
Put your truck in low gear (lever next to parking brake) and it will act same way. Forward and reverse.

Idle should be 5-600 I believe
Correct number will be in the TM.

 

[Isawfrizzy]

It's not the torque converter acting any different.
Like mentioned above, it's the reverse gearing.
Its very low. I do not recall the ratio
Put your truck in low gear (lever next to parking brake) and it will act same way. Forward and reverse.

Idle should be 5-600 I believe
Correct number will be in the TM.

OK. Thanks. I'll check it out.

 

[98G]

Do NOT put your transfer in low range, and your transmission in reverse unless you want to replace the transfer.

 

[Tinstar]

Normal backing is ok on flat ground with truck empty.

But he's correct
The transfer case can't handle a lot of torque in reverse

 

[Isawfrizzy]

Do NOT put your transfer in low range, and your transmission in reverse unless you want to replace the transfer.

Thanks. I knew that and it's stenciled on the inside of the passenger door in red letters.

I figured it's a pretty big deal but I thought it was don't back in low range with the front end locked in. I have a ball valve installed in the air supply to the front locker so it can't auto engage unless I open that valve.

 

[Jbulach]

My idle is just under 600 RPM and will still idle up hill in reverse with the low reverse gear. As for low range, even empty, the shock of shifting into reverse at 800 RPM could break the transfer case.