Hey guys, got a Cat 730 rock truck, prefix AGF I have some interesting problems with - Customer told me it had some shifting problems, code 585-2 active, found output speed sensor damaged, replaced and no active codes - This did not fix the issue, it gets into 2nd gear, tries 3rd and immediately dips back to second, noticed reverse will not engage either - Another issue that cropped up was the unit would not start unless I jump the starter relay, put new relay on just to confirm as I had it with me. Same problem - I suspect the issue is with the transmission gear select sensor as this seems to be the neutral start sensor also, someone had a wiring attempt in here also unfortunately Anyone ever come across this before ? Calibration for the shift control seems arbitrary, tough to tell if it actually worked. Thanks!
Not 100% sure if I'm thinking of the correct prefix truck or not. If I am then that model of truck is notorious for transmission failure. If memory serves me right, it was Caterpillar's highest failing component at one time.
The first thing I would suggest is a transmission filter cut and an inspection of the transmission suction screen & magnets to eliminate the possibility of a mechanical issue. The torque converter on that machine has a lockup clutch and a one-way stator. It wouldn't surprise me if the ratchet mechanism was starting to fail.
Yeh thats what I initially thought, we are the 3rd techs out to fix this unit..... Oil is clean apart from usual wear and tear. The strange thing is I have zero codes active, I even calibrated the clutch fill and it was succesful without so much as a warning.
Is there a calibration for the shift control lever.? I don't think so but may be wrong. I would suggest putting a gauge on the lockup clutch pressure test point (located on the upper LH side of the transmission on the modulating valve) and see what it does while the transmission is shifting.