2-3 shift

[bob69302]

Hello,
I'm hoping you fokes can help me once again. I've tried to search but I'm using my phone so it's a little hard. My M998 shifts very fast (almost don't even feel it) from 2nd to 3rd. First is perfect and so is higher speed kick down (3rd to 2nd) so I hate to adjust the cable. Any ideas how to make the trans hold 2nd just a little longer?
Thank you for all your time and support.
Phil

 

[Retiredwarhorses]

You have to adjust the modulator....but that's how they come from the factory.
your not really supposed to feel it shift....

 

[WalterMitty]

I have the 3speed, and 1-2 is easily felt..seems sorta of a harder shift. 2-3 is really smooth...like said above, almost unnoticeable.

 

[1 Patriot-of-many]

I don't notice any shifts in mine.

 

[bob69302]

Thank you for the reply. Does the modulator have the screw inside where the vaccum hose connects? And the motor revs up good in first and has a strong shift into second but then hits 3rd almost right away. I would like to hold second a little longer to allow the motor to pick up a few hundred RPM and come back on the torque curve before going into 3rd. Will adjusting the modulator make this change. Also I can't remember but I think clockwise on the screw will raise the shift point RPM?
Thanks again!

 

[Action]

shift by hand then. you can let it rev as high as you want before shifting...

 

[bob69302]

I got my 10.2 SBC car with a TCI full comp reverse valve body I can shift if I want. I know I can shift it manually. My original question was the 2-3 shift. Why it happens so fast and how to fix it. I'm not looking to spin the motor high, just looking to really use 2nd gear. Why apply the band just to immediately shift into 3rd gear? Seems like a waste of application to me. She carries 1st gear perfectly, then hits 2nd and right away 3rd. Hope this makes sense and I didn't piss anybody off.
Again thank you to all.

 

[Bulldogger]

I have the same issue as bob69302, second to third shift in nearly instantaneous. 0-15 MPH in first, then second and then third a split second later.

Is the modulator the issue, and how does one adjust it? I see in the TM a reference to checking it, but I can't find any details. The TM vol 1 states there is a modulator cable connected to the throttle, and it influences the transmission shift points, but the TM only mentions checking that the cable moves when the throttle is depressed.

I can't find anything in the TM using a search that indicates how to adjust the shift points.

Bulldogger

 

[Bulldogger]

Hey bob69302, I have the same problem as you, as noted previously in this thread. This weekend I did some driving, making sure to manually shift and make the trans use second gear when I wanted it. As of this morning, she now uses second gear longer! It is still a quick jump between 2-3 in regular takeoffs, but with the hammer down from a stop I get 2nd at about 15mph and then 3rd doesn't kick in until about 28mph. I think a little more driving using the shifter manually might free my second gear up properly.

Just an idea for your to try.

Bulldogger

 

[Action]

I don't think your HMMWV computer is learning new shift points. It is likely the placebo effect.

 

[Bulldogger]

I don't think your HMMWV computer is learning new shift points. It is likely the placebo effect.

I disagree. Transmissions have complex innards, and like any mechanical assembly can be affected by time and neglect. I think mine forgot it had a second gear, i.e. internal valves or passageways were a little crudded up or some such (I did replace the filter and fluid). I feel certain I was not getting as much time in 2nd before I shifted manually a while. My HMMWV sat for about 10 years, if I take the notation of Feb 2006 on the air filter as an indication of maintenance and use. I am still clearing out figurative internal cobwebs in the engine and drivetrain. I've put about five tanks of diesel, with treatment, through it now and the more I drive it the happier it is. I see this issue as one among many, all related to being sedentary for a long while.

Bulldogger