Hey everyone, today my 2013 mustang gt with 98k miles and the automatic 6r80 transmission had an alarming transmission issue.
The car has been sitting for a little over 2 weeks in my apartments parking lot with much of that time spent covered in snow and ice. I went out today and cleared all the car off and dug around the wheels and behind the car so i’d be able to get out. The battery was dead so I jumped it using my daily driver explorer.
Car started after a jump no problem at all and ran/idled smoothly. I waited for 2 or 3 minutes for the car to idle and allow all the fluids to circulate. I then proceeded to put the car in reverse to back it out of the parking space and felt and heard an EXTREMELY hard CLUNK. I was a little surprised since it had never done this before, so I put it in park and then once again shifted into reverse to feel the exact same very hard clunk once more. I backed out of the space, put it in drive (noticed there was no clunk when going from reverse to drive) and began driving down the road. The first thing I noticed was that the car wouldn’t shift out of 1st gear. Or maybe it was 2nd gear I don’t remember. Either way, the rpms kept going up and up but the car wouldn’t shift into the next gear. I thought maybe the car had gotten locked into a gear by accident (although I don’t think this is possible if the car is in regular “D” mode) but nonetheless I shifted the shifter down into sport mode because when you do this it will display what gear the car is in on the gauge cluster display screen. Well when I put it in sport mode nothing showed up on the screen, like the car didn’t even recognize it had been shifted to sport mode. The screen didn’t display anything either when I pressed the upshift/downshift buttons on the shifter while shifted into sport mode. Just nothing.
I pulled into the closest parking lot and parked, shifting into reverse one more time just to confirm what I dreaded, feeling the extremely hard clunk once more. I just sat there thinking about where to call for a new transmission, then put the car in park and shut it off.
A couple minutes later I decided I should try to limp it home since I was still pretty close and when I turned it back on and shifted into reverse it shifted COMPLETELY normal. No clunk whatsoever not even in the slightest. Smooth as can be. I tried putting it in park again, then reverse once more and again, absolutely not even the slightest clunk. I then tried shifting to sport mode and the display screen lit up saying “SPORT SHIFT MODE” then when i pressed the up/downshift that’s on the gear selector it cycled through all the gears on the screen. I then proceeded to drive the car and now it drove completely normally shifting through all the gears 100% fine no slipping no delayed shifts, when before it was refusing to shift at all. VERY strange.
I have an OBD tuning device that tells me trans temperatures and the temp has never gotten above 190 in all 18k miles of my time of ownership including today. I am positive there are no leaks in the trans because I would have seen fluid all over the ground from being parked for so long, not to mention would have smelled it and also the temps would be through the roof if the fluid was so critically low that the car wasn’t shifting or having problems reversing.
I’ve never had any transmission issues before with this car and it certainly had never done that before ever. I got the car at 80k miles and first thing I did was change the trans fluid and filter myself, original fluid came out dark red NOT brown or black, then I drove it for a few thousand miles and got a second drain and fill and filter change done at the dealership just to make sure the most of the old fluid was gone and the new fluid was as clean as possible. Now 18k miles later absolutely no trans problems until now.
Could what I described be the beginning of the end for my transmission? to me the problem almost certainly seems like something electrical since the trans went from working 100% the last time it was driven 2 weeks ago to 25% and then back to 100% within the span of a few minutes. Can someone share insight about what could have caused this and if I should be worried?
I have a few theories. Can someone tell me which, if any of them, are the most likely to be correct? Or something different entirely?
1.) it was pretty cold outside (33 degrees or so) and maybe the fluid wasn’t circulating properly since it was very cold outside and the car had not been started in 2 weeks, however I waited 3 minutes after starting the car before putting it into gear plus i’ve driven it in way colder temps before without issue so I highly doubt this is the cause.
2.) maybe some snow got stuck in the u joint on the driveshaft and this prevented the car from shifting or being able to recognize twhat gear the car was in? However if this were the case wouldn’t the car not move at all then?
3.) I have a trans tune from VMP performance to optimize shift points. Maybe since the battery died some of the computers parameters got reset, while still thinking it was on the trans tune, however this makes no sense because the tune stays loaded onto the ECU so theoretically it should override any factory parameters that would be reset if battery was disconnected
4.) the car is very low to the ground. Maybe some sensor in the trans got wet from snow being under the car and sitting there for so long causing damage and then when I turned on the car things began to warm up, drying out the sensor causing it to act erratically when the car was still cold but then fixing itself when the car was turned off and back on with everything also being warmed up.
5.) there is a serious internal transmission issue that appeared out of nowhere and I will need a rebuild soon. Despite my fluid being clean and full and me rarely beating on the car and when i do so, i make 100% sure it’s at full operating temperature. Also trans was working perfectly fine 2 weeks ago when I last drove the car and never had an issue before
6.) a fluke that has no reasonable explanation
Any help appreciated