Do the torque converter and the transmission have to be replaced at the same time? on 2003 Acura MDX

I have an MDX with 185K miles I took it to the dealer for the 180K mile service which consisted of flushing various fluids. I told them that I had noticed that the car's mpg had dropped from 20.5 to 18.5 and that I was noticing the tach jumping from 1500 to 2000 when I was driving between 35 and 45 mph. They said the torque converter is going bad and that I would need to replace both the torque converter($2500) and the transmission($5000). I ask about replacing only the TC and they said that if I replaced only the TC then I would be back in in 6 months to replace the tranny and I would need and another TC. They also said that I should not flush the transmission fluid. Why? If metal is in the fluid wouldn't flushing it be a good idea? To their credit they said since it had 185K miles, I should just drive it until it dies.

by in Raleigh, NC on December 29, 2010
2 answers 1 comment
ANSWER by on December 29, 2010
Transmissions when replaced will always come with a replacement torque converter along with them. This is because typically when a transmission fails it sends metal throughout the assembly. You can never really flush a torque converter in the shop well enough to prevent contamination from an old converter from getting into a rebulit or new transmission. So, they come with one. I am a little miffed that they are estimating both a transmission and a separate torque converter. Why don't you call to verify that information - even try a second dealer for information. Flushing the transmission fluid is never expressly recommended by Acura. Even as non-recommended proactive approach, I agree that it is probably worse to flush your transmission fluid at this time given your concerns. You may actually accelerate failure, as debris may move to a catastrophic location.
ANSWER by on January 01, 2011
What Dave said is very true. But I just did one for my friend who had the same problem but it also had a bad shudder and we just replaced his converter and fluid and it is doing well. It was just the cheaper fix. But by the sounds you may need both. But like Dave said a new tranny will have a new converter.
COMMENT by on November 02, 2011
Can you tell me where you can buy just the torque converter? My repair shop is having trouble finding one. I would really, really, really appreciate help!!!! :)