I was wondering if I can get some of your input on a really loud grinding noise on my 98 Dodge Ram 4 x 4. It is such a Loud god awful sound like gears grinding. I have had this problem for about 6 months now and because my truck is not my daily driver, I have been putting it off because of lack of funds. With winter coming soon I will need to drive it again.

The grinding noise only happens when the truck is under load, so if it starts I can usually stop it instantly by letting off the gas. It used to only do it only very rarely, but it has progressed where almost any sort of load will trigger it. It sounds like it is coming from the transfer case (231D) or in that area.

I have checked u-joints
Checked fluid in transfer case
Checked fluid in front and rear differential

I have been saving for a used transfer case for around $300 from the local junk yard. But after looking at a few forums I am starting to question about rushing in and replacing it.

Someone thought that if the truck is out of 4 wheel drive and only in 2 wheel drive then you wouldn't hear any issues with the transfer case. Mine makes grinding noise whether in 2 wheel or 4 wheel drive. (any input please)

Also I read about

The rear most snap ring being broken. If I take the tail shaft housing off and find the thing in parts laying in the bottom will my transfer case most likely be destroyed anyway or would this being broken cause these symptoms.

Center Axle Disconnect defective (I wonder about this because it is controlled with vacuum and I know I have a vacuum problem as I have "crazy vents" but my 4 x 4 works so I don't know.)

Loose or broken chain in transfer case. Just wondering if this difficult to replace.

Sorry for the long post just hoping someone might have some ideas or things to check for.

Thanks

 

Yikes, if it is the chain then it requires taking out entire tcase and separating the 2 halves to disembowel it. lol

Just some thoughts here to help diagnose is whether you have jackstands and floor jack?

With the tires up off the ground maybe try putting tranny/tcase in neutral, then go under and spin driveshafts by hand to see if the noise occurs?

 

I actually tried that "lifting car on stands and while in neutral spinning drive-shaft" I did not hear any noise.

 

Fix the wild vent problem first. You have a vac issue for sure. When in 2wd it needs full vac to the cad , to keep the collar there.


https://dodgeforum.com/forum/2nd-gen...ild-vents.html

http://www.dodgeram.org/tech/repair/..._engagment.htm

 

zman17,
If I understand what you are saying, if I loose vacuum while in 2wd then the cad will put it partly in 4wd which would cause a grinding gear noise. If this is true than it makes sense. I loose my dash vents when under load because there is not enough vac to keep the vents door open. I only have this grinding noise while under any load and as soon as I lift off gas grinding noise stops, or if I just barely give any gas then I am ok.

Either way it is worth trying. I won't be able to check till Tuesday but I will post my findings as soon as I can.

Thanks

 

Sounds about right to me. Fix the vac problem, if the grinding goes away, great, if not, at least the vac leak is fixed.

 

I finally got a chance to start trouble shooting again. I marked where the front drive shaft position was and while driving around I would stop and look to see if it has moved. It never moved then I heard the grinding noise again and stopped to see if the front drive shaft spun at all. Sure enough it spun and my mark that I put on the drive shaft was no longer visible.

I read several post saying that it always moves and some say that the front drive shaft doesn't move in 2wd. So I am confused.

I disconnected the vac on the cad and tried again. I spun the front drive shaft so my mark was on top and checked periodically while driving and it remained stationary I heard no noise. But then again I could hear the grinding noise and the position has change on drive shaft.
A friend with a 95 dodge ram came over, I marked his front drive shaft and we drove around. His front drive shaft did move.

But what is different between mine and his is I can spin my front drive shaft all the time. My truck can be in park with engine off and it spins freely. The 95 Ram is solid and won't spin freely with it in park or engine is off. I am wondering if this could be my problem.

 

I'm pretty sure the 2nd link that zman posted about says what is spinning during 2wd.

 

Wh1t3NuKle,
I reread that second link, according to that the front drive shaft shouldn't be moving while in 2wd. My friends 95 always move in 2wd or 4wd. I talked to him and he said his 4wd light was always on when he bought the truck, but he removed the light instead of fixing it, he forgot to mention that. So I am guessing his vacuum switch may need cleaned or replaced and his interlock may not be releasing which causes extra drag. Looks like we may fix a problem for him he didn't even know he had.

Since my drive shaft does spin at random while in 2wd and that is when I hear the grinding noise. Im going to look for a vac leak again, I looked today and couldn't find any buy I know one is there. I will also look for a vac tester so I can test the vac diaphragm on the cad. Any other ideas or suggestions?
Thanks again everyone for you help

 

Glad you checked that out. Here is a thread for additional info.

https://dodgeforum.com/forum/2nd-gen...-problems.html

You say it's confirmed grinding noise happens when under load/driveshaft spins. Have you considered disconnecting the front DS at the pinion. You may be able to secure with a bungee or just disconnect completely. Try to reproduce the noise from driving.

Could also put up on jack stands and turn the pinion by hand to see if grind occurs. It should turn freely.

Those are my suggestions so far.