hello,

i have a 1999 dodge ram 1500 sport, auto 4WD. 116k miles.

ive been trying to figure out what the problem is but ive had no luck.

whats happening is when i let off the gas and coast or brake to stop there is a clunking sound coming from the rear of the truck, once i give it gas it stops.. then comes back when i let off. at very low speeds you can almost feel a slight jerk as it clunks.

im not sure where to begin as this is my first truck ad i dont know a whole lot about it yet .... any suggestions would be great, thanks

 

What do your rpms look like? Any check engine lights? What does it do at idle in park?

 

rpms look normal, my check engine light is on, when i tested it , it said misfire in cyl. 6..... i didnt think that was related but just one of the other things wrong with it, that im trying to figure out lol..

in park or drive if im not moving its fine, runs normal . it only happens when im coasting or breaking.

 

Is there any other way to describe the noise/feeling? I know it's tough over the internet. Try to be a specific as possible. Is the noise constant while braking/coasting? Random? Same noise/loudness every time? What does it do at takeoff? Does it depend on anything like engine temperature or weather conditions?

 

it sounds to me like it coming from the rear end, the best way i could describe it is it sounds like someone is tapping on the rear end with a hammer and i can feel the vibration in the floor under my feet.

takeoff seems fine, the noise only occurs when im not giving it gas, if im slowing to a stop and then hit the gas the knocking stops once i accel.

the sound is timed with how fast im going, its not random.. i cant really hear it going over 30 mph, once i get below that i can hear it knocking fast and as i slow down it slows down and seems to get louder. as i come to a stop it feels like its about 1-2 knocks per tire rotation. it happens the same way every time.

engine temp hasnt mattered really, but i think the knock has gotton worse in the summer, it wasnt so bad in the winter... i just assumed whatever is knocking is getting worse.

i hope this all makes sense. thanks for your reply!

 

i think i might go get an oil change and let them change the fluid in the rear end... or would that matter?

 

Removing the diff cover is a good idea. Depending on what you find, you'll know right away. BTW, you should check the ujoints on the drive shaft.

 

+1 check u-joints first. its the most likely and least expensive problem. should be NO play in the joint. if that's ok, put rear up on jack stands and rotate by hand. if not obvious start it up and put it in drive and run the drive train at low speed to see if you can duplicate the problem. (be careful of moving parts) figure out where its coming from first. if coming from the chunk, then remove cover and inspect.

 

checked the u joints today, they seemed fine. i noticed it didnt make the noise for the first few mins of driving. also it does it in reverse too.

 

Will it make the noise with the rear up on jackstands? have you pulled the cover yet to inspect?