Engine flutters and bogs when shifting while driving in 4lo.

[Snow1er]

So as the title states. I was cruising with the family in the San Juans this last week and a strange phenomenon happens. When I am in 4lo going slow and the vehicle shifts I can hear a flutter noise as the rpm drops (awe exhaust). In 4lo it shifts so much it wants to be in 6th gear doing 10mph and the rpms are super low. It almost feels like it either bogs or over-revs. I try to keep it in drive in 4lo because below 2nd gear at around 3mph idling downhill it lulls and revs up and lulls back down. This flutter does not happen in 4hi or 2hi.

With 35s and 4.88s the gearing is low enough I usually stay in 4hi and hold it in 2nd gear at 10mph.

Vehicle: 2022 Jeep Gladiator Willys.
I bought it stock with 20k miles on in less than two years ago.

Current setup:
Metal cloak game changer 3.5 kit with driveshafts. Rocksport reds. Sway disconnects.
4.88 gears
35x11.5 falkien wildpeaks on method wheels.
Awe trail tuck exhaust.
Afe snorkel, filter and intake pipe.
Amsoil oil changed at 50% since I bought it.
Artec front and rear bumpers
Lietner rack.

Any input would be helpful.
Would going to 37s maybe help??

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[PuddleJumper]

That's normal operation. Sounds like your using 4lo but not adjusting your driving habits. the flutter is backfire being arrested by the exhaust. If your not using offroad plus mode the transmission will attempt to shift using normal 2hi programming parameters. IE try to speed shift as high as possible. I recommend using manual gear selection when using 4lo and don't be afraid to let the RPMs wander a bit. obviously don't redline it everywhere, but use the gears to hold 1800 ish rpms at whatever your desired speed is. If it still seem "unweildy" you may be using 4lo when it isn't needed, and 4Hi may yield better and smoother results.

 

[Snow1er]

That's normal operation. Sounds like your using 4lo but not adjusting your driving habits. the flutter is backfire being arrested by the exhaust. If your not using offroad plus mode the transmission will attempt to shift using normal 2hi programming parameters. IE try to speed shift as high as possible. I recommend using manual gear selection when using 4lo and don't be afraid to let the RPMs wander a bit. obviously don't redline it everywhere, but use the gears to hold 1800 ish rpms at whatever your desired speed is. If it still seem "unweildy" you may be using 4lo when it isn't needed, and 4Hi may yield better and smoother results.

Thanks for the reply. I believe since my vehicle has the most basic interior ( crank windows, manual locks, tiny screen) i do not have offroad plus mode.

Just to elaborate the flutter, when shifting, sounds similar to a coasting deceleration with burbles and pops, something you would hear when going from low throttle downhill to no throttle. Only the sound is muffled or fluttery. The thing, for me, which is odd is this is happening going uphill between shifts with a similar sound and flutter.

I agree it is possible that even with the willys "not as low 4lo" (not the 4 to 1), that 35s and 4.88 gears make 4lo too low even for steep colorado shelf roads.

 

[PuddleJumper]

Thanks for the reply. I believe since my vehicle has the most basic interior ( crank windows, manual locks, tiny screen) i do not have offroad plus mode.

Just to elaborate the flutter, when shifting, sounds similar to a coasting deceleration with burbles and pops, something you would hear when going from low throttle downhill to no throttle. Only the sound is muffled or fluttery. The thing, for me, which is odd is this is happening going uphill between shifts with a similar sound and flutter.

I agree it is possible that even with the willys "not as low 4lo" (not the 4 to 1), that 35s and 4.88 gears make 4lo too low even for steep colorado shelf roads.

not really such a thing as too low, moreover your traveling a speed to high for your 4lo. the fluttering is normal, mine is far more aggressive.

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