05 Silverado no power in 2wd and 4 hi

[Country270]

Hey y'all I'm hoping you guys can help me out, I put my 2005 Silverado 1500 5.3 4x4 in the mud tonight and when going through a hole ( I know it wasn't bad my buddy had his Chevy same as mine only 2 years older and was going through the holes in 2wd that I had to lock into 4lo to get out of ) I had no power in 2wd and 4hi I had even shifted down to first gear thinking the tranny was still is 2nd gear. The rpms would not rise over 1000 and this was with my foot to the floor the rear wheels wouldn't even spin. I locked it in 4lo and my truck crawled right out with no problem, but still acted sluggish in the low rpms, this has got me stumped . I'm not transmission savvy so not sure if this could be a issue. I bought this truck brand new and it now has 86000 miles on it and the tranny and transfer case have never been serviced because I was told to wait till 100,00 miles by the dealer is this correct or should it have been flushed and changed before now. I am also running after market wheels and a set of 295 70 r 17 Cooper Stt Mud terrain. Thanks for any advice

[chevybulldog6]

How did the engine sound? Was it idling rough? I had something simalar happen to me and it was nothing more that a mud covered air filter. I cleaned the mud off and finished the day.

Hopefully it is something small like this. If not, give us a little more info as far as engine sound and how it runs on the road after this.

[Country270]

Engine seemed fine no rough idle, just seemed to take a second to jump when I pressed the gas, also no mud or water on the filter. When I was in a hole the rpms just refused to climb in any gear unless I had locked it in 4lo and even then starting out took a extra second to get up and go

[CowsPatoot]

Does it rev freely in neutral, or is it sluggish then too?

[Sierraowner5.3]

could be u got the O2 sensors wet. i did that in my old 05. it acted real funny till they dried out.

Alex

[Country270]

To be honest I never tried to rev the engine in neutral but on the road it shows no sign of this problem, I press the gas and it gets with it' this only happens in soft sugar sand or mud low traction situatios

[Sierraowner5.3]

could be the torque managment system getting a little over zealous. computer is trying to protect the drivetrain by keeping the power low. the 4-Lo shift tells the computer to open it up because you NEED the power.

with those bigger tires in the soft stuff the truck is hooking more, ergo, harder to turn over and spin em. this is just my guess tho, i could be way off.

Alex

[Country270]

Guys I sure appreciate it, ill keep yall informed if I'm able to figure this out