Q: I have a 2008 pontiac grand prix and it will go in reverse but not in drive.

Check to be sure the gear shift linkage is actually moving the "manual lever" on the transmission case into the forward gears. If it is really shifting, then check fluid level. Low fluid level, or a clogged filter, can cause transmission movement problems. If fluid is adequate, the manual lever moves, and the filter is not clogged, the likelihood is the forward band is broken and if that is the case, typically the entire transmission is rebuilt (I have rebuilt the one on your car; the 4T65-E; they are not difficult at all; much easier than an engine). If you want a conclusive diagnostic, please use YourMechanic’s shift failure diagnostic service request page. If you request that diagnostic, the responding certified mechanic will get the underlying issue identified and let you know of your repair options and costs. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.