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Wayne, Journeyman
Category: Heavy Equipment
Satisfied Customers: 9633
Experience:  34 years experiance as engine rebuild and problems.Thermo-King repair and trouble shooting.
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Kenworth..shift lever..low range..high range, the noise and clunk

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I have a Kenworth with Eaton diffs and a regular power divider/tandem lock A heavy load was hauled and the truck bogged down and a gear was missed in high range. Since then, there has been a cyclic banging sound, heard through the driveline as well as felt in the shift lever, but is very hard to detect when in low range. As soon as the truck is shifted to high range, the noise and clunk are there within seconds. (it's there under deceleration as well, but much much more heavily felt under torque). It should be noted that when the clutch is shoved in or the stick put to neutral while moving, there is no noise or clunk felt whatsoever.The diff lock engages and disengages when jacked up on the shop floor, but when test driving it or attempting to have it lock while tested against a snow bank with rear wheels on ice, only the front drive wheels spin, and the clunking can be heard very easily. My first thought was something in the transmission, (it seems to shift fine), but both sets of rear wheels should spin in this test case. Could the power divider itself be broken and the dilff lock actuator still working? Any insight would be valuable before something is taken apart for no reason.
Hi I'm Wayne,
I will help you with this,

Very good question, I had t o read this 3 times, to make suer I understood it
The part that is con fussing is when you you go from low to high,
I want to say , diff, is broken, but I don't under stand why you do not hear it in low,
Unless............the front diif. is doing the pulling, but you say a ice/snow bank
no 4 wheel,
I have to go with the rear diff, cross shaft broke,
drain oil and see what you geet ,
Metalic, heavy, and/or chunks, this is where your probem is

If this helped you , please hit Accept, as this is the only way I get Paid,
If not get back to me
Customer: replied 5 years ago.
Hi Wayne,

What does seem to be happening is that the front drive only is pulling. That's what we saw when we did the ice surface/snow bank test. Jacked the back end up in the shop, the rear wheels would lock and unlock with the switch in the cab, but they were turned by hand and not under engine power, yet the jackshaft turns fine and there is no binding or effort to spin it or the rear wheels (manually). The sensation you get from this when driving would be similar to locking in the divider while spinning or going around a corner. When beside the truck in the snow/ice test, the sound can seem to be pinpointed near the divider and the drive shaft "hollow clink" is more evident than when driving it. It feels almost like a lock attempt but gets thrown out with a bang. As I mentioned, it's there in low range too, but you can hardly sense it or feel it. Driving it with the cab switck in lock or unlock makes no difference, but the actuator is verified to be working. Maybe more strain on the driveline with load when in high range, so whatever is broken cries louder? Could the divider itself or the gear set inside it not be broken and preventing power to the rear drive under any load?
Is this some thing you need to know now, I would like to think on this, and go into my books ,
I have rebuilt many rear ends,
I would like to research this a little

Forgot to ask,
what rear end are we talking about, Rockwell...........

Customer: replied 5 years ago.
No Wayne, it's not an emergency. The mechanic figured it could be run because it's local only and it hasn't changed sounds or got worse (been 3 days). But I'd like to know what I'm up against before I just let them take everything apart or have it explode with a trailer on and need towed. Those sounds and lever vibs don't give a person much confidence when pushing the throttle.

Check into it and get back to me when you've had time, and I'll gladly top up your fee for helping me out. (no problem there my friend) Asking the right questions and getting well thought out answers can save plenty of time AND money when problems like this come up.

They are Eaton DS (402/405) I believe. Eaton for sure. Model number on a sheet in the truck (not home with me)
Good Morning,
After thinking about this , rereading your questions, and answers, 6x,
I have come to the conclusion, that it is a tooth broken in the rear case of trans,
Reason being, (in my Opinion) the noise is louder in high range, a gear was missed in high range, depress the clutch, or put in neutral, noise gone, gear stops turning,
To double check my self, I called a ol'timer I worked with,( we retired 2 years apart,)
printed this out and went to his house this morning, we both read it several times,
He agrees with my thought, the tooth missing in back case,
so without a big ordeal, of tearing things apart,
drop the drive shaft and pull the rear cover off case, I am sure you are going to find a bad gear .
I hope this helped you,

PS we are both early risers, we met for coffee at 6:30Am
Wayne and 2 other Heavy Equipment Specialists are ready to help you
Customer: replied 5 years ago.
Thank you very much Wayne, This was my first thought as well (transmission) and although it there in low range too it's hardly noticible and someone who never drove the truck would never know until they went to high range. I'll have this looked into before any differential components are taken apart. Missing that gear in high under heavy load and then doing a hard forced shift would do exactly what you describe because it put some kind of a jolt through the whole truck. Again, thank you very much.
You are more then welcome,
I like questions, that make me think, rather then a
simple one, keeps me on toes,
When I start to question myself, I know I have correct answer,
but like to confirm it at times,
if you need any more help in future , please ask for me


PS they XXXXX out all personal info