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Bob_Jeannie · 06-30-2015, 12:12 PM

When we purchased our 1998 Dutch Star DP Cummins C8.3 with Bosch P7100 a year ago, I noticed a shudder while accelerating. Didn't think a thing about it at the time. The more I drove it the worst the shudder ... then we got what felt like very bad drive train vibration during acceleration while in San Francisco traffic . A few days got back from that 1,200 mile trip into California from Oregon ... we barely made it back home. About 45 miles out the coach would slow down on flats and hills .. down shift and finally start gaining speed again. Got it home and checked the fuel for water, fuel okay. Removed the fuel overflow valve from the Bosh P7100 injection pump and found a weak spring on the ball check (it was the original part). Ordered another overflow valve .. replaced it without bleeding air from the system ... made it down the street before the engine died. Pulled the primary fuel filter off, it was half empty. Filled the filter with diesel and got back home. After checking the lift pump and fuel pressure to the IP... I took the coach out again today. All that was needed to get rid of the transmission shudder and drive train vibration was replacing the weak overflow valve. Apparently the Allison Tq converter was locking and unlocking due to the engine not making enough power.

Dave Fernandez · 06-30-2015, 01:00 PM

Hello & Welcome to IRV2 Bob;

You might want to check the Drive Shaft and the U-Joints as they can cause the shutter you are talking about when they go bad.

Bob_Jeannie · 07-01-2015, 10:35 AM

Quote:

Originally Posted by Dave Fernandez

Hello & Welcome to IRV2 Bob;

You might want to check the Drive Shaft and the U-Joints as they can cause the shutter you are talking about when they go bad.

Thanks for the welcome and your insight

it's appreciated

David K · 07-12-2015, 07:28 PM

I have experienced the shutter before with my coach. What I eventually found out was that the last service shop had replaced by second fuel filter with a too small micron filter and the engine was starving for fuel but, it felt like the tranny or U-Joints were failing. The smallest micron filter recommended (by Cummins) for my 8.3 ISC is 10 microns and that is what I run for both of my fuel filters.