I have a 2005 Mini Convertible CVT (automatic tranny, not S model) and am having some troubling downshifting issues (described below). I had an issue and just got the thermostat, housing, and gasket replaced, as well as the air filter. Yes. At 18K miles and I already had to replace those parts.
I’ve had the car 3.5 years, and I only have just under 19K miles on it (live in the city and use it mostly for local driving). I wasn’t having any transmission problems before the replacement (although when the therm problem started happening a month ago, I’d avoided highway driving until I could get it fixed). Now that that is fixed and the new air filter is in, I definitely have more pick-up… BUT…
When I accelerate through the gears (automatic, CVT), I can go up to 75-80 with no problem. I decelerate by just letting up on the gas lightly, and everything is fine until the car gets to about 60-65 mph. When I get to that range, the gear kicks down, and it starts engine breaking (that’s fine if it was limited to that). But it stays at about 3500 rpm until I either break hard (tranny shifts again, RPMs drop, and behaves normally) or give it a lot more gas (the rpms instantly decrease if I give it a good amount more gas, but it revs even harder if I depress the gas pedal even a slight bit more. should be the opposite, right?).
If I let up / semi-coast down to about 55, and give it just a bit of gas, even though I THINK it’s still down a gear because it, at 60, is still above 3100 rpm and only slowly descending, giving it a little more gas gradually jumps it back up to 3500 rpm. If I gun it (the trigger to actually make it downshift), the RPMs drop back to 2600 or so and I can speed back up normally. The car is supposed to respond to more pressure on the gas as heavy acceleration and at that point, drop gears, and go. But it’s already dropped a gear or two, so when I give it good gas at that point, it physically thrusts forward very well, but the engine sounds and tach indicate that it’s actually shifted up a gear rather than dropping.
No matter how many times or ways I go up and down gradually through this 60-68 mph zone, the engine is revving harder than it should and jumping erratically through gears. It’s downshifting / decrease in RPM is counterintuitive, as it’s behaving the opposite as one would expect (dropping a gear on a gradual deceleration while raising a gear on a strong acceleration).
It’s a 2005 Automatic CVT convertible. Again, I just had the thermostat adjusted, and I’ve driven it more than 100 miles since the repair, so it shouldn’t be a computer reset issue. On that repair, I replaced the air filter. It has 18,900 miles. The only gas I’ve ever used was either BP or Shell top-grade (at great expense to prevent this type of BS, I might add).
I called the mechanics who worked on it for the therm repair (despite the mileage, I’m out of warranty because it’s 3.5 years old). The guy on the phone said either low tranny fluid or gear slippage. Reading other posts online that it’s a closed system, if it’s gear slippage, it looks like I’ll have to replace the entire tranny, at HUGE expense. If I have to pour 7K into a car with less than 20K miles on it, there’s a MAJOR problem.
Does anyone have any advice? It’s odd that this shows up after the other repair, so maybe it is a computer issue. But looking this up online, I’m seeing all of the tranny issues on Mini. I don’t want to walk into the mechanic saying “I need to fix this…what’s wrong” because I’m going to get screwed. I’ll be very appreciative of any advice as to what could be wrong and other questions that could be asked to pinpoint a problem. Thanks in advance!
I love my mini. I love the way it drives. But I did NOT pay $27K on a car for it to cost $8K a year in repairs when it has less than 20K miles on it. That’s not the way I “roll.”
Cheers!
Michelle
I don’t know if you will find many Mini gurus here. Yours is a very obscure car with an even more rare transmission. You need a Mini specialist, possibly the dealer. If this is a big issue with Minis, they will know. There may even be an extended warranty or an “easy fix” TSB for it. In all probability the CVT has a faulty sensor causing your woes. Google “Mini Cooper Group” and take your pick of online groups that will pop up. Ask your question there.
Was the thermostat replaced because the car was over heating? Some of the behavior you noted is what you’d expect from a CVT transmission. You have less gears inside there and more “belts” and variable pulleys. Did the mechanic disconnect the battery when doing the work? If so, perhaps the transmission has to “relearn” the shift points.
If the car is acting very different and you are concerned a “mini” dealer service is about the only option you have. Even transmission shops may not have much experience with this vehicle.
I agree with MG McAnick. You’re probably going to have to take this to the Mini dealer. There may be a computer fix for the CVT problem, which I don’t think is related to the thermostat installation.
You say you had the thermostat, housing, and air filter replaced at 18K miles. The car is four years old. How does this translate to $8,000 a year in repairs?
Thank you all for your advice… I appreciate it!
And mcparadise, the $8K a year was in response to possibly having to replace the transmission, which it appears that lots of others have had to do since the Mini transmission is a closed system 
mc
If you are saying a lot of Mini transmissions are failing at 20K miles then you need to get a lawyer and see if the “lemon” law applies. If mfg lets the word get out that they have this severe a problem the car’s sales are going to tank. You seem to be informed about Mini owner’s groups perhaps some transmissions are getting replaced by mfg under “extended” warranty.
My '04 T’bird got extended warranties from Ford after many, many owners complained about failing ignition coil problems. Now there is a 100K and 10 year extended warranty coverage on those items.
Work the dealer, work the mfg zone rep for some answers.
Welcome to those of us who fell in love with the WRONG car! I purchased a used 2004 automatic Mini from a local dealer. It came with a 100,000 mile warranty. That is the only reason I purchased the car which had 44,000 miles on it. At slightly more than 60,000 miles, the automatic transmission failed out of the blue with no warning. This same dealership (in fact, the same salesperson who sold me the car) tried to tell me my car’s transmission wasn’t covered under the warranty. I practically yelled and screamed at her…reminding her I never would have purchased the car from HER if major problems hadn’t been covered. She managed to get the replacement of a NEW transmission covered under the warranty. The car runs like new…which it did up until the minute the transmission failed! Now, having checked on the Edmunds.com discussion forum, I have learned this transmission problem is a very common problem with automatics. Bad clutches are a problem with manual transmission Minis. I plan to keep the car until it reaches 100,000 miles and then dump it. What a shame!