I have a 1998 1500, 4x4.

I was backing the truck up into my garage and I noticed a knocking sound. It seemed as if it was coming from somewhere in the right front wheel area.

I backed up slowly. It only made the sound as I crawled while backing up. I've never noticed it before, but then again...I don't drive it much. There is a very slight incline to my driveway into the garage. There was no sound while I was in reverse but not moving (so probably no engine related). The sound is very hard to describe on a forum, I know, but...almost like if you had a padded metal rod or something and knocked on a control arm or something.

How would I go about diagnosing this? I was thinking it was possibly the front driveshaft related, or the u-joints. I am praying it is NOT the transmission. It shifts into all gears fine and smooth, so I hope you won't say it's that.

The truck was NOT maintained well by the previous owner and I suspect the u-joints are all needing replaced because they are all very rusty (I'm surprised they are actually still on the truck).

Any thoughts?

thanks,
pf

 

the front drive shaft only turns when its in 4wd, so unless you have it shifted that way, its probably not drive shaft u-joints.

it probably is axle u-joints. jack up the front end, remove the tires, stick your head in there and turn the wheels. look for movement in the u-joint. grab both sides with your hands and try to twist. should be no movement.

 

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

read that and click the link on the second post to watch the vid.

https://dodgeforum.com/forum/2nd-gen...984-uh-oh.html

also read this one. hopefully if you change the u joints you don't mess up the axle seals.

 

Thanks for the info and the links. I checked the video from Sheriff, and that is exactly what I heard. Too bad it's such a pain in the a$$ to change stuff in the front end. My front driver side axle seal is leaking, so I know I have to do the seal eventually, but it looks like a pretty big job.

Sheriff, when you changed your seals was it a PITA to do the passenger side? I went to Pavementsucks.com and it said something about having to build a seal driver out of nuts, washers, and sockets. What did you do?

 

i made a slide hammer with a piece of threaded rod (11/16"), washers, nuts to hold on the washers and the head off a 5 lb sledge hammer. looking into the cad unit i saw the threaded rod through the center of the new seal with a washer the same size as the outer edge of the new seal on the threaded rod with a nut on the very end to hold the washer on. the outside of the rod had a nut and washer on it with the head of the sledge hammer (no handle) on the inside of the washers with the rod through it. i also used my hub nut socket to keep the threaded rod centered in the axle.
i was on the ground under the truck with my left hand on the big washer and my right hand on the socket in the end of the axle tube with the threaded rod going through the center. i made sure that the washer and seal were lined up and had my dad give the slide hammer a smack, then i had him push it into the axle enough to look at the seal and make sure it was going straight. about 10 or 15 light hits later the seal was driven all the way in and i just had to put the axle back in.
there is a stop in the axle tube for that seal but i measured the old seal to the outer edge of the tube anyway to make sure that the new seal went in all the way.
before you put your axle back in you ought to hit the sealing surface on the end with some 600-1000 grit sand paper to get all the rust/mud off just in case you drive the seal a little too far.
and yes the driver side is a pain. if you are determined then you could get it changed out in less than 6 hours. i wasn't so it took me a couple weeks. i took the wheels/brakes/axles/cad unit off one day then called it quits. then i took the carrier out another day and put the new seal in and called it quits. then another day i got the covers sealing surface cleaned up and installed and put the axles/brakes/cad back on and called it quits. then another day i finally got the wheels back on and drove it and found out after a few miles that my passenger seal was leaking.

and i wouldn't say that its a pita to change the seals/u joints but i will say that its pretty involved.

one thing i did different than the pavementsucks diy is i used a come along to get the carrier out. i lined my dads hitch up with it and put a small chain around the center of the carrier right up against the ring gear and i was under the truck to catch it while i had my dad slowly crank on the come along. i would have just pryed it out but i don't have tall jack stands and i had the truck sitting on boards on top of blocks so the front end was pretty low.
it was a little easier for me too because i took my drivers side tie rod loose from the knuckle to change the boot on it and i didn't have it in the way of the carrier.

man that was a lot of typing. i forgot to answer you, the passenger side isn't that hard if you have a helper to work the outer end of the slide hammer. and a socket would be too wide to fit in the cad unit unless you took your intermediate shaft out, thats why i used a washer the same size as the seal. don't forget to add 5 oz. of gear oil through the hole that the 4wd indicator switch is threaded into when you're done.

 

Sheriff, thanks for the detailed reply. I haven't torn it apart yet, still waiting on parts. Also, since I haven't seen the inside of the D44, I have no idea what you're talking about when you say remember to put 5 oz. of gear oil in the hole that the 4wd indicator swict is threaded....Where is that located?

I'm new so this went totally over my head.

Thanks,
pf

 

its the sensor on the cad unit that has a wire plugged into it. the haynes manual says to take it out and squirt 5 oz. of gear oil into the hole that it was threaded into. the cad unit is on the back right side of the axle and it has a wire, vacuum lines and an overflow hose attached to it.
you don't have to mess with the cad unit unless you're changing the axle seal. so if the passenger side is not leaking then you just need to pull out the axle to change the u joint on it.