The past couple of weeks shifting from 1st to 2nd was getting more difficult along with a grinding noise. Now today, my brother drops off my car in a Metra parking lot for me to drive home from the train. I go to get into the car and immediately feel that the shifter is loose / not right. I start the car and put it into reverse to back up out of the spot and my car goes forward like it is in 2nd gear. I tried maybe 100 times with no progress. Then I noticed that my shifter would not stay in 1/2/4/5 position. Called R/A and they came to tow it, 1 hour later I get a phone stating the tow truck had broken down and they were sending out another one. Going on two hours later they finally came only to have another problem with this tow truck. Finally they got it up on the lift and took it to the dealership. Just got a phone call from them stating that is most likely the transmission / they have not seen this before and it will take til at least Monday to figure out exactly what is wrong. This car was bought brand new, march 2012 it now has 4100 miles on it. Extremely frustrated right now.

Chevy has not been able to fix this issue of the trans grinding when shifting from 1st to second. And I mean it really grinds bad!! The longer you drive it and the hotter the lubricant in the transmission gets the worse it grinds and at lower RPM's. At first the dealer told me I was beating the car and speed shifting at high RPM. I am not speed shifting and shifting well below the red line so I disagreed with them. The mechanic then duplicated the grind and agreed with me but had no knowledge of how to fix if. I did some research and this trans is a RPO code of MZ4 which means it is an Opel trans model M32-6. This is the same trans in the Chevy Cruze ad the Cruze has the same shifting problem that they can not correct.These transmissions have been used in Europe in many different model cars for many years and there does not seem to be any issue with them in Europe. So why does it grind in the US and not Europe? What could be different. I check the recommended fluid type for the Opel trans and it is SAE 80. I then tried to find out what lube Chevy recommends and the owners manual says consult your dealer, the dealer says there is no spec because it is a sealed and lubricated for life unit. It has only, a fill plug on the top of the case, no fluid level plug, or drain plug, and there is nothing in their data base-NOTHING!!. I then consulted 2 independent transmission shops and asked them what they thought and they both said the same thing. Their thought is that the input shaft is really spinning fast on the 1st to 2nd shift and that the syncronizer is not able to slow the shaft down enough to allow a smooth shift resulting in a grinding shift.Why is this different in the US trans than the Europe trans? My thoughts and every trans man I talk to say it is because the lubricant in the US trans is way to thin and slippery and there is no friction or drag for the syncronizer to do it's job. The hotter it gets the thinner the lube gets and the worse the grind. Why wont Chevy/GM tell me or print the spec for what the lube is? I believe they know this is an issue and have done everything they can do to get fuel mileage out of their fleet to meet the CAFE standard levied buy the government and have used a very thin lube in this trans to help meet that CAFE standard.The same reason they are using motor oil with weights of 5 and even 0-zero! I have read in my internet search that some owners are sucking the lube out and replacing it with 1.7 qts. of lube from Red Line, MT-90 Lube, 75W90 GL-4 Gear Oil, and that this has solved the problem. I asked Chevy and they said if I do this on this sealed for life trans I will void my warranty.I asked if they could drain so lube out so we could look at it to judge what weight it is and see how much metal is in my trans and the answer was again, that is sealed for life and the fluid can not be drained. It looks like me only option is to keep grinding it until there is some much metal in the trans that it causes a bearing failure and the Chevy will have to replace it under warranty.

Update from Jun 11, 2012: Chevy has replaced the transmission with a brand new trans and the new on grinds worse than the old one. I then convinced the dealer to finally try changing the manual trans lube with Red Line MT-90, 75w90 GL-4 lube and presto the grind has stopped. I have been driving the car for a week and it has not made the 1-2 shift grind once. So the fix has been found for the Sonic trans grind and should also fix the Chevy Cruze trans which is having the same issue.