New oil pump

[JMBT]

Well I started her up for the first time today after the rod and main, and new oil pump job. (CM 2250, 764K) The truck runs smooth, but at high idle about 850-900rpm there is a “howling” noise coming from the bottom front end of the motor. When I get under the truck it sounds like it is coming from the brand new oil pump or at least right there on the oil pan. When driving I can only hear it when coming up to a stop. Oil pressure is normal idling and driving.

The gear lash was well within spec off the truck and also when mounted. I also pre-lubed it so it didn’t start dry. I did notice the wider gears of the new pump run at a different spot on the crank gear. Could that be the howling? Or did I get a brand new but bad part?? (I just read an article claiming nearly 30% of all new parts are bad) or maybe it is fine but it’s just going to be noisy?

Any ideas?

[Unilevers]

if its howling its because something isnt right with the lash on the oil pump gear. They do not howl normally, cummins has a TSB out about it if you look it up.

[JMBT]

Thanks Uni, I’ll look for the TSB. The lash seemed fine though. The pump itself idler to drive gear was .006” off the truck. Then mounted up it had .017” at the bottom gear. Which makes the idler to crank .011”, the spec said .003”-.022” Where I am showing .011”

[JMBT]

Unilevers, I can not find the TSB you spoke of. Do you remember where/when you saw it? Thanks

I just keep thinking when I put the new pump in and looked up at how it mated to the crank gear, I noticed that because it’s gears were wider then the ones on the old style pump,***(not correct)*** they touched the crank halfway on the wear marks left by the narrower gears of the old style pump and halfway on “new” previously untouched surface on the crank gear teeth.*** Zoom way in on the pic and you’ll see it. Sorry for the weird angle.


Seems like everytime Cummins “updates” something they F it up somehow!

[marek4792]

I think it is TSB200038 and as always the big red engine maker is good as useless.

[JMBT]

Thanks marek4792! Well by that bulletin they say just leave it alone because they don't have a fix for it yet. Man I wish I would have seen that before I replaced my old style pump. I think if the pan comes off again, I'll put the old one back on....

you are exactly right....they are useless

[JMBT]

Damn, I just went for another cruise. It really sounds terrible. Worse with warm oil then with cold. I am really debating pulling the pan again and putting the old one back on. I wonder if the noise would fade a bit as it wears in?
Any thoughts?? Thanks

[Unilevers]

yes that is the TSB i was talking about. There is also another about worn crank gear teeth causing oil pump noise but i got to find that one. i think its TSB160042.

i have not noticed any excessive noise here from the new pumps. if its really that noticeable something may be wrong. Im not sure i would wait to see if it wears in.

[jimeneztrans84]

My 2011 kw t660 makes a howling noise at low speeds 15mph and under ever since I got it used with 455k. A guy on you tube said after he swapped out his air compressor it went away. Mine sounds like it's coming from left side of engine but I only hear it at low speeds.