01 Malibu slow shifting to reverse

My 01 Malibu transmission recently started taking 5-10 seconds to engage after moving the shift lever from nuetral to Reverse (??). No Check Engine light... Car has 43kmiles.. I changed the tranny filter and fluid at 33kmiles. Runs great other than this .. (except the theft system light is always on...)

Anyone have any suggestions or ideas? Thanks in advance! :)

Update:

The problem with my tranny turned out to be an internal reverse seal failure. At only 43kmiles - Not good…

I took the car to a dealer to have the pass-lock sensor replaced (theft system was coming on intermittently which prevents the car from starting - had to wait 10 minutes each time it engaged before the car could be started). While it was in for the pass-lock repair, I had the tech scan for tranny codes – none found. I then took the car to a transmission place (recommended by the dealer). The tranny tech found the reverse line pressure to be low. The tech said this was the first time he had seen this problem, He removed the tranny and found the bad seal. They did and excellent job … fixed and out the door for $750.

So, after $225 for the passlock sensor, $750 for the tranny repair , an earlier warranty 3.1 lower intake gasket repair, 3 sets of brakes, and a bad window switch, I decided to cut my losses and trade for a new car. My original intent was to keep the Malibu for ten years but it wasn’t looking like it would make it. I hope I don’t regret it but I bought another Chevy – 04 Impala. Got a great deal – 04 Impala MSRP was 24.5k. I drove away for $11k plus my 01 Malibu. By the way, I was also surprised at the low the resale values are for Malibu’s. MSRP on my 01 LS was 19.5k. Around here an 01 Malibu LS with 40-45kmiles is selling at auction between $4k-$6k.