Mysterious Drivetrain Issue in 2003 Ram 1500

[Kodiak351]

Hello! This is my first post here (or on any forum), so I hope that this doesn't violate any rules in any way. I have a 2003 Ram 1500, 4WD with 4.7L V-8. About a week ago, driving a friend home in the snow (in 4wd) the engine began to lose power. Well, not necessarily the engine lost power, as the revs didn't drop, but the power was not getting to the wheels. I took it out of 4wd, and put it back in, thinking that maybe the transfer case was not fully engaged, but it did it a couple of times more before I got home. Not a loss of traction, nor a loss of engine power, but power not making it to the ground. When I got home, I checked the transfer case, transmission, and rear diff fluids, and they all looked good. Driving to work for the next week, though, the problem grew steadily worse. I do need a new U-joint bearing at the rear differential, and hopefully will get that repaired next weekend. But I didn't think that explained the major issue. Now, the problem has gotten so bad that making it to work is extremely difficult. I put the truck in drive, accelerate, and for the first moment it goes, but, while rpm's stay steady, the truck simply stops moving forward, as though it is in neutral. But not exactly like it's in neutral, as revs will usually shoot up if I was to actually put it in neutral. If I carefully ease off the throttle, the truck will re-engage, and slowly move forward. The only way I can drive it is to keep the rpm's as low as I can, but on hills, the truck sometimes comes to a near standstill, even though the engine is revving at 2500 or higher. Yesterday, I jacked up the rear tires and spun one side by hand (truck was in neutral). The other tire spun in the opposite direction, as expected with an open diff. But just barely, and then it would stop spinning even though I was spinning the other tire by hand. And the axle also would stop spinning. By changing the direction or speed of my spin, I would see both the other tire and axle try to move, but they wouldn't spin. Only by stopping, and very gently starting again could I get them to move again. This behavior was identical whether I spun the passenger or driver side rear tires.

I wonder, does anyone have any idea where I should start on working this out?

 

[chopperman1]

Your transmission needs work/rebuild, it's slipping. The rear is working exactly as it's supposed to

 

[Smokeybear01]

Your trans is about to give up the ghost. That's my opinion FWIW. Sorry

 

[GTyankee]

pull the trans dipstick, smell the tranny fluid, does it smell like almonds ?

How does it drive when you are only using 2 wheel drive ?

 

[Kodiak351]

Thanks for all the advice- I think I may have tracked it down to the transmission speed sensor getting water inside. Replaced it (and oxygen sensors while at it), and so far, it's been running normally. The real test will be if we get any more rain or snow, though.