My 2021 Forester developed an issue at approx. 12,000 miles. Sometimes when starting from a stop, it will briefly have the sensation of a transmission slip at around 5mph, then "catches" and goes on normally. 0-5 normal, slip/bump around 5, then normal. I'm not talking about the higher revs that some people confuse for slipping- I'm very familiar with the CVT now and find that to be normal. This particular issue feels as if a chain on a bicycle slips and then catches, or if a gear is missing a few teeth. I know this is not the case, but I'm attempting to describe the sensation. A brief slip/jolt, then on my way. Almost like an abrupt clutch dump of the last bit of clutch travel on a manual, following an otherwise normal release speed- think a new driver learning.
Background: I got an oil change at just under 12,000 miles, right before a roadtrip to the mtns. The trip involved 8+ hours of highway driving, with several hours of it on some fairly large hills at high speed. The issue developed soon after returning from our trip. That said, on the way home we noticed some jerky behavior at highway speeds during light accel on flat ground.
Went to the dealer, they did not notice anything. My passengers did notice, and made comments. It's not un-driveable, but it's really annoying. I went online and found some info on a reset procedure that seems to be a throttle reset? It fixes the issue initially, but the issue returned after a few weeks. I lived with it for the remaining 6k miles until my next change. Following my oil change at 18k miles, the stuttering at highway speeds got much worse! I finally made the drive to some flat ground to check the oil level, and it was 1 inch over the "full" mark after sitting for 30 mins. I took it to the dealer and they adjusted the level, after confirming my findings.
My theory is that the 12k oil change was somewhat overfilled, since the 18k change was really overfilled. I've exhausted myself trying to get answers from the dealer, and it really seems to be a waste of time. I did the "throttle reset" again following a confirmation of correct oil level, and it seems to have fixed it, though I can't tell if the slip issue is creeping back in. Everything is happy at highway speeds, which is nice
My question: Does anyone know what could cause this kind of behavior where it feels like a brief slip? If there is a part that was damaged by the oil overfill, what could it be?
Please- I'm looking for technical help, not advice on fighting my dealer, or criticism of my delay in checking the oil level. Thank you for understanding.
Background: I got an oil change at just under 12,000 miles, right before a roadtrip to the mtns. The trip involved 8+ hours of highway driving, with several hours of it on some fairly large hills at high speed. The issue developed soon after returning from our trip. That said, on the way home we noticed some jerky behavior at highway speeds during light accel on flat ground.
Went to the dealer, they did not notice anything. My passengers did notice, and made comments. It's not un-driveable, but it's really annoying. I went online and found some info on a reset procedure that seems to be a throttle reset? It fixes the issue initially, but the issue returned after a few weeks. I lived with it for the remaining 6k miles until my next change. Following my oil change at 18k miles, the stuttering at highway speeds got much worse! I finally made the drive to some flat ground to check the oil level, and it was 1 inch over the "full" mark after sitting for 30 mins. I took it to the dealer and they adjusted the level, after confirming my findings.
My theory is that the 12k oil change was somewhat overfilled, since the 18k change was really overfilled. I've exhausted myself trying to get answers from the dealer, and it really seems to be a waste of time. I did the "throttle reset" again following a confirmation of correct oil level, and it seems to have fixed it, though I can't tell if the slip issue is creeping back in. Everything is happy at highway speeds, which is nice
My question: Does anyone know what could cause this kind of behavior where it feels like a brief slip? If there is a part that was damaged by the oil overfill, what could it be?
Please- I'm looking for technical help, not advice on fighting my dealer, or criticism of my delay in checking the oil level. Thank you for understanding.