Hey everyone, over the last year I've gotten to know this Cummins diesel pretty well. Last year when I went to shift it into 4H I could hear a small clickity clickity when it was trying to engage. 4L would perform solid. It did that little thing for the past year now until yesterday, when I went to shift it into four hi I don't think I even grabbed at all, I ended up getting stuck in a river and having to throw my overhead camper off into the river to get out of this nasty jam I was in. Anyways I don't have 4low and I don't have 4high and now it is grinding somewhere even when I'm in 2wd. Feels like it's directly underneath my feet. This truck may look like **** but it is a solid river truck it has never gotten stuck before. I put people to shame with this thing 4foot in the water pulling people out.,, up river even !!! I love having a short bed Cummins diesel!! Any advice is welcome.

 

Sounds like the shift collar isn't engaging the axles, probably due to misalignment or leaky diaphragm.
Check the two lines at the CAD for adequate vacuum. If that's OK, pull the CAD and see what you got going on inside.

You getting L range with the trans. case?

 

I think your internal shift collar is probably worn out...and maybe even more since 4hi is no go.

Put up on jack stands, engine running to get the vacuum, put tranny in N to decouple, and shift tcase to each position. Manually spinning the driveshaft(s) to check engagement. It's safer, provided everything is secured properly. This will also help evaluate if anything is going on with the CAD shift collar like mentioned. I wouldn't open it up yet until ruled out that front really won't engage.

 

Does the front lock in with vacuumed lines..? Yes, for the longest time the 4high was working excellent and the four low was working excellent even though it was popping like hell before it would finally lock in. I know I have a few vacuum lines that are not hooked up and I'm not sure where they go. I haven't even looked under the truck yet. I'm just trying to get all the advice and bone up on what I'm going to need to do to diagnose this problem. But, as of right now, The four low and for high will not engage, it sounds like a pile of trash driving down the road in 2wddrive. I don't even plan on moving it from where it's at right now without getting it up on jacks like you mentioned. Something else I can remember, it would pop like hell for maybe five minutes or about a mile until it would lock in. And once it was locked in it wouldn't slip out.

 

Can you explain what the CAD is..? I've only done the fuel systems on this truck. Earlier this year. That was quite an adventure for me to learn without a experienced mech on hand. The whole fuel systems upgraded all the way to the plugs from the fuel tank now. I'm pretty new to drive drain.

 

CAD = Central Axle Disconnect

On the passenger side axle tube is access to the axle shaft where this is located. There are a total of 3 shafts that are used for the front drive. Driver side is short and always turning. Passenger side is 2 pieces. The CAD is the location where they become engaged.

Vacuum must be available 100% of the time for 2wd to work properly as well as 4wd. The CAD functions to contain the shift fork that is pulled by vacuum. Hence, lock down all vac lines.

Read this to familiarize yourself.

http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm



Example picture of my old front axle showing the red line broke.

 

Thanks, I'll check it out.