Hi, 2011 Genesis Coupe with 130k miles. Automatic transmission (ZF 6hp19) downshifts to 5-6k rpm when I floor it on even roads and the car has good pulling power but when I floor it on steep inclines (say 15% or more) it only downshifts to around 4k rpm and doesn't pull well.
Original transmission - No error codes - Changed the fluid about 2 years ago when I got the car (The mechanic didn't use ZF recommended fluid saying that the ATF fluid he used could replace it, I'm not sure about that!)
If it was done two years ago and still shifting fine I would have to believe the fluid is irrelevant and not the concern. It could be due for fluid change again otherwise it sounds normal. Car will never pull as hard going up hill. There is a lot more rolling resistance as well as now trying to pull the weight of the car up a hill will always lower rpm and reduce pull cause the cars working harder
I would agree, but the other day I had a 1.5l supermini in the overtaking lane (same incline), and when it finally pulled over for me to pass, my car (3.8l) downshifted to 4k rpm and really struggled to pass and I had to downshift another gear manually to pass. how am I to know whether the transmission is slipping or not? Is it a safety feature for transmission to shift to lower RPMs on an incline?
If it was slipping the rpm’s would shoot sky high not stay lower so it doesn’t sound like a slip condition
I think your speed on the uphill was not slow enough so that computer did not down shift. There is nothing wrong with it. About your question regarding damage to transmission, putting load on transmission is not a good thing and in the long run results in wearing out your transmission.
Thanks for your answer 👍
Do you recommend changing the transmission fluid with ZF's recommended fluid? It has run on this fluid for about 20k miles and I have had no major issues so far. If yes should I replace the transmission pan/filter again? (replaced it the last time)
20k miles is nothing for the ATF. With that said, inspect the fluid and if it is not as new, you can go ahead and change it, but do not flush it.