The 4 wheel drive in my truck works perfectly some times and others it will just not engage at all. Every once in a while it will engage but the 4 wheel drive light will start to blink even at low speeds.

I have not checked under the truck yet because I am waiting on a messed up knee to heal but just wondering if anyone had some guesses.

I would think maybe a vacuum line but that wouldn't really explain why it works perfect some times.

I did a search because I thought I saw something about this a week ago but could not find anything.

 

here is all you need to know. When you get better, buy a vacuum gauge and follow the directions. http://www.dodgeram.org/tech/repair/..._engagment.htm

 

I've read on here that the vacuum line can be the problem. Also it could possibly be burrs on the shaft preventing the fork from engaging. Buy a Posi-lok and cap that vacuum line at the engine. then you'll know that it's engaged. I still think my has some burrs as it's hard to engage the cable sometimes but it will engage and when it does it doesn't come out. Posi also gives you 2wheel drive Lo range so you get the lower speed in reverse. Great for backing trailers and such. I've 2wheel lo more than 4wd this year since we haven't seen much snow. The posi is a cable that installs under the dash and when you pull it, it engages the forks on the axle providing a no guess approach. It takes a little getting used to and you definitely need to pull the cable while rolling. If you get stuck and try to engage you'll have trouble. The key is to jerk that cable BEFORE you need it and pull your shifter to 4wd when you need it!

 

Forget about all the vacuum lines and get this
http://www.4x4posi-lok.com/app_dodge.html

Just pull and bam, you are engaged. Easy to install.

 

Thanks for all the replies, I will take a look at the cable system.