mp3car

Hello. I have a 2005 AT and have recently noticed an issue with, what appears to be, the transmission at 45mph in 5th gear...

It seems like the transmission can't make up its mind whether to lock the torque converter or not... When I hit 45mph from coming up from a slower speed, it will still be in 4th. However, if I take it up to 48-50mph, it shifts to 5th. If I slow down a touch back to 45, it stays in 5th, but it seems like the torque converter locks, unlocks, locks, unlocks, etc, causing a slight up/down oscillating change by around 100-200RPMs, with a frequency around 1Hz.

2005 MDXs had this EXACT same problem, but Acura recently (1 year ago maybe?) made a new software load for the AT and Acura reprogrammed it free of charge. I called to check to see if TLs have been reported to have a similar issue, but they have not seen any.

I am going to swing it by the dealer tomorrow to show it to them, but wanted to post on here to see if anyone else has had or heard of this issue before...

I doubt this could have anything to do with it, but I just had the dealer change the transmission fluid in October (for only around $90, I figured I'd just let them do it). I can't say for 100% certainty whether this is an issue that surfaced after that or not...

NBP04TL4ME

You are correct about the MDXs. We had what sounds like something similar with our 07. Torque converter would lock up, but not readily release and downshift. RPMs would bounce 200 - 300 rpms. Ultimately we had the torque converter replaced under warranty. Recently had recall work done for catalytic converter which apparently included a software upgrade. Now it seems like the shift pattern has changed and will stay in lower gear (4th) until we reach a higher speed (45+). Seems to me like all we have done is impacted MPG as it is holding 4th gear longer. Am going to discuss next time I have it in.
Can't help you with the TL as mine is a 6 speed.