Hi, 01 Diamante w/134K miles. No problems at all until this week.

2 days ago, my transmission would not go into drive for 5-8 seconds after starting the car in the morning.

I checked the transmission fluid and it was a little low, so I topped it off - no change.

If the car is "cold" (it is summer), if I pull up to a stop and the RPMs get below 1K, the transmission kicks into N. If I brake and rev it up, it will kick back it.

Once the car warms up (5 minutes) the transmission stays engaged.

I have read about the heater core issue and am wondering if this isn't the issue but I have no wet carpets and there isn't a smell. There is a bit of film on the inside of the window. (but I haven't washed it in a while)

The trans. fluid doesn't smell burnt and is still red.

Any ideas? Thanks.

when was the autos last service

just let the engine and gearbox warm up by ideling

a bit longer than you have been ,before you take off

A leaking heater core/condensor case leaking fluid onto the PCM-TCM will cause transmission issues

also the trans relay is under the heater core..... can get wet and burned too

Im glad I stumbled onto this post....I am having the exact same issue. My tranny is very sluggish when the car is cold. It sometimes takes up to 5 seconds to shift into D or R from park. I hope my tranny isnt going out. cant afford that kinda repair right now. I had it flushed 3 days ago but it has not helped at all.

Any suggestions??

Thanks guys..

YU may wanna service the fluid RellyOh, also teh screw on filter on the transmission. BUt yu can check the relay also for the TCM

I have to find these component locations..also I thought it was not recommend to replace the tranny filter and I think that is a dealer part

RellyOh , on yur models transmission , on Mitsubishi's F4A4 , F4A5 ,F5A5, W4A5 , W5A5 series transmissions frum 1992-2000 (F4A4 series) and 1995-2000/2001 for the the F4A5 ,F5A5, W4A5 , W5A5 model transmission had an internal non servicable filter ( this filter can onlee be serviced when the transmission is torn down) and an external screw on transmission filter which is located near the transmission range switch. It is highly recommended to replace this filter when servicing the fluid. Which on yur model which is a F4A51 transmission which debuted on american Diamantes in 1997 up with 1997-early 2000 being the onlee ones with the external servicable filter. after 2000 all these models , the external screw on filter was discontinued , with the non servicable internal one being the sole filter. Even F4A41 and F4A42 in american Galants and Mirage's with 4cyl had external servicable filter til 2000.

In the Intake and Induction there is spossed to be a section on replacing and fluid change

I will have to find a place to purchase the filter...I believe only the mitsubishi dealer sells that part.