We recently rebuilt the transmission to our car and about a mth later the light

Yes we still have the warranty.. We took it to a mechanic that was recommended to us and they said we had worked on all cars. The check engine is on and the transmission light is the one that comes on and off. We rebuilt it because it no longer got gears 2-4 only reverse. The trans light comes one about once a week but once car is turned off it will go away and then pick up gears just fine. We were told that the trans was being completely rebuilt with all new parts so didn't expect it to start so soon. Do you think it's the trans again or could it be something else causing that.

If the check engine light is on there has been a code set in the system, and probably some history codes are in the system. The codes should be diagnosed, by a qualified tech and repairs should be made. Yes I would take it back, was there a check engine light on when you took the vehicle to the local mechanic, or not? Yes it could be something else, did you check at a dealership for technical service notices, or recalls? How many miles are on this vehicle? Now BMW has their own computer system, so in saying that the dealership may be your best alternative for their computer system, and they are more informed than the local mechanics on some of the high-end vehicle issues. Did you purchase this vehicle new or used, you know not everyone follows manufacturer recommendations on their transmissions, and its not fair to the tranny. Fluid change intervals and proper maintenance is a priority, in any vehicle.

It's got about 190,000 miles. He bought it used.. We have had the codes reset but it still comes up. We have had the computer put in it and there are several miss fire codes. The engine light came on after the trans was changed. When we drive it kicks back and when driving slow forward or reversing it vibrates like it wants to turn off

The check engine light being on , transmission not shifting properly, and misfires. A diagnostic check is needed, this could be a number of issues that are leading to one or more of your problems. I know that it is hard to take in, when you have problems early on in your vehicle purchase, that lead to stress, and frustration, but when you buy a high end vehicle, when and if something does go wrong it may cost a little more to take it to the dealership,but their parts, and diagnostics in most cases are more accurate. You have codes that are set, and they need to be verified, and addressed. Some computer scanners at other than dealership facilities may not pick up all the codes. The codes are the way along with other signals that we are able to properly diagnosis your vehicle. BMW vehicles have numerous sensors that send information to the main computer. Your problems are growing, have you did any other repairs? at this mileage there should have been several services performed on this vehicle, such as tune up, fuel filter changes, or have you check the service intervals/ owners manual for this vehicle? Or called the dealership to find out what services are needed? and yes there are many miles to go once these issues are resolved, diagnostics at dealer may be needed, at least to find out what the codes are, and for you to get a better understanding of the services that this vehicle needs.