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Showing results for tags 'tach'.
2016 Silverado 1500 5.3L 6-speed RWD. 106K miles. Note: this is a possible root cause based on my towing 300+ every couple of weeks, in addition to heavy cargo. Also, my driving habits may have been on the lugging side. Bought used at 33k, first 30k modest work driving (tolerable cargo, 70-30 highway-city). Symptoms: (After trouble-shooting a poorly mounted injector pump-another post on that) if rpms were below 2500 and I was giving slight more throttle, tach would bounce 100-200 and I could feel a shudder (couple of times heard a grinding/clicking). Never got a code-took to dealership but they wouldn't diagnose it. Was using valvoline atf, did an exchange 20k early, no change. Drove it 6k until i could get to a trans shop (in manual and tow). Diagnosis: Trans pump was failing, possibly because Valvoline never replaced the filter, or just age (and driving). They had to also replace TCC, so final $ was around 5000. Stick with a Tranny shop, have the filter replaced everytime, and stick with the Dextron 6. Also be aware of other codes that may put more strain on the pump.
My good friend, who I help keep running, has a 1993 C2500HD- the one w/ the TBI fuel injection on a 5,7L block & the Eight Bolt 2WD hubs/rims. It's been running ok for a long time w/ more than 430K miles, mostly freeway, on the OD. It does though have a few nagging issues, one of which is the tachometer bounces up and down erratically while the motor is running. It's most pronounce when the RPMs are low, like around 1K-2.5K, but never really goes away. The truck also has trouble sometimes pulling up-grade without getting some pinging from the motor. (Usually running 87 roz/ron octane...), I mention it in case the two things are related (Jumpy Tach & slight but persistent 'ping' going up steep grade on the freeway) in case they are related.