Forester Auto Trans Grinding & Stuck in Limp Mode

Had nearly identical symptoms with a 2015 Subaru Outback at 135000 km. The transmission cooling system showed similar warning signs, grinding, rough shifts, and limp mode activation. The actual problem turned out to be a failed transmission control module connector. The cable connection had corroded, causing intermittent signal loss between the module and transmission. This triggered the transmission to default into emergency mode as a safety measure. A proper leak detection test showed the cooling system pressure was normal, ruling out radiator issues. The car overheating warnings were false readings due to faulty electrical signals. The repair involved: Cleaning corroded connector pins, Replacing the main control module harness, Resetting transmission adaptive memory, Full transmission fluid exchange This was a serious electrical issue that could have led to complete transmission failure if left unaddressed. The repair completely resolved the rough shifting and warning lights. Would strongly recommend having a specialized transmission shop perform detailed diagnostics. They can properly test the cooling system pressure and electrical connections before assuming internal transmission damage.

That is exactly what happened to my 2013 Forester last winter. The symptoms matched perfectly, rough shifting, warning lights, and the transmission going into limp mode. The cooling system pressure test turned out fine, but we discovered a failing oil cooler that was causing transmission temperature warnings. My repair needed replacement of both the transmission control module and oil cooler lines. The cooling fan also needed adjustment since it wasnt engaging properly at the right temperature thresholds. Curious what you paid for your repairs? My total came to around 1200€ at the dealer. Have you noticed any other issues since the fix? My transmission has been shifting perfectly for the past 8 months, but I still do regular coolant leak checks just to be safe.

The repair costs were much lower in my case, just 95€ to fix the faulty cable connection on the radiator oil pressure sensor. The mechanic found the problem quickly through systematic leak detection and electrical testing of the cooling system components. Since the repair last year, the transmission has performed flawlessly with no warning lights or rough shifting. The cooling fan now engages exactly when it should, and regular coolant level checks show no signs of leaks. The key was catching the electrical issue early before it could cause actual transmission damage. A proper diagnosis saved me from an expensive transmission overhaul. Regular cooling system maintenance and checking for coolant leaks will help prevent similar issues from developing again. The radiator repair fully resolved the transmission warning symptoms, confirming it was an electrical fault rather than internal transmission wear. The cooling system now maintains correct pressure and temperature regulation.

Thanks everyone for the insights. Following your advice, I finally got my Forester fixed last week. The main issue turned out to be a damaged wiring harness connected to the pressure sensor, causing false transmission warnings. The mechanic did a thorough inspection of the cooling system and found the coolant leak was minor, just needed to replace a worn gasket. They also cleaned the corroded electrical connections and installed a new transmission control module since the old one had partial damage from the faulty signals. Total repair came to 850€, which was less than expected. The car overheating warnings disappeared completely, and the transmission shifts smoothly again with no grinding sounds. No more emergency mode or warning lights. Best decision was going to a transmission specialist rather than the general repair shop that initially misdiagnosed it. The cooling fan cycles normally now, and I plan to have the cooling system pressure checked regularly as preventive maintenance.