The RPMs went up, but it was as if the transmission was in neutral?

MJG82

MEMBER
2004 DODGE TRUCK
5.7L
4WD
AUTOMATIC
175,000 MILES

I was driving up a hill and heard a loud metal breaking clang, instantly my RPMs went up, but it was as if the transmission was in neutral. I put it in Park and the transmission seemed to hold it. I tried 4-wheel drive and the same nothing but engine revving. I put it in neutral and coasted until I came to a stop not because I was ready but there was some resistance. I couldn't even budge with 2 people on level pavement. Any ideas would be greatly appreciated. I'm going to dig in tomorrow.

Sunday, December 10th, 2023 AT 2:30 PM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

Since you can't push the truck in neutral and you hear a noise it could be the transmission is okay and the rear differential is the problem. Let raise the rear for the truck (parking brake off on level ground) and see if you can turn the driveshaft.

This guide will help:

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

If you can't turn the drive shaft, remove the rear cover for inspection, use a flashlight to check the pinion and rings gears. Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on. Have a fluid catch basin ready because gear oil will come out.

https://www.2carpros.com/articles/differential-service

Please go over this guide and get back to us.

Images (Click to make bigger)