Legend2TL

FWIW, here's a extremely comprehensive YouTube video of the TLX/MLX SH transaxle with the electric motor/generator by Weber State University Professor John Kelly .
Kelly does some phenomenal video's where he explains and shows the operation of actual transmission that are taken apart.

mrgold35

I wonder if it is the exact same 7DCT for the RLX and MDX? It would be nice if true and the MDX could handle the same 377hp/341tq also

jdpdata

Pretty sure they made the MDX lame to avoid cannibalizing their own RLX or now the Type S. Would be nice to have a 377hp/341tq MDX. I didn't realized how under-powered the MDX was until I drove my RLX back-to-back.

KenRLX

I have seen a number of those videos from John - always informative and well done.
In particular, during the GM A8 fluid change journey to (finally) a usable tranny without shudder, his videos were quite helpful. The videos provided information about how to set the fluid level that was better than the service manual.

I did change the fluid on the A8 a couple of times, but then the dealer did a change under warranty when the 'good' A8 fluid was finally released.

Related to the current SH and my past A8 experience, I am about to do a fluid change at 6k miles during the holidays for the SH tranny and twin motor unit. Partly as an overall precautionary measure, and also to avoid the reported shudder on the SH. Shudder is just not good for those friction plates John describes so well. Usually the first tranny fluid change gets rid of a lot of suspended particulate matter.

Anyone seeing all those parts of a tranny and how just one failing part brings it all to a halt, would think a lot harder about more frequent fluid changes.
IMO, manufacturer statements that tranny fluid is a 'lifetime' fluid is just a way to get more cars sold over time.

jdpdata

If indeed the MDX and RLX share this same 7DCT setup, I would like the know why the MDX does not have EV mode in reverse? I really enjoy backing up my RLX into the garage with whisper quietness (other than the UFO sound). So strange that the MDX can't do this.

mrgold35

Acura really dumb down the MDX hybrid system compared to the RLX. Getting 29-30 mpg in my RLX in 25-45 mph city driving should be duplicated in the MDX also (MDX is only 100 lbs heavier). I'm like you, I thought my MDX hybrid system was outstanding until I drove the RLX hybrid. Now my MDX hybrid makes me sad.

CadiGTi

Thank you Legend2TL for posting this. Once again Acura does not know how to toot its own horn. The 2005 and up RL and the RLX had some great tech that Acura just never did a good job promoting to the general car buying public. If only Acura had an old school "Iacoccoa" type engineer/marketing guy! I was a supplier to GM when Cadillac made "Northstar" and "OnStar" household names almost overnight with their brilliance in marketing even though most of their products (ie Northstar) were compromised mediocre engineering efforts.
At least in the early 1990's Acura was a tad bit more brash with the "Some Things Are Worth The Price" marketing campaign. Selling just a hint of Prestige with the Acura brand. And I have to say those Acura's were well worth the price, without qualification! The marketing matched the product.

rlx015

How are the 7DCT from the maintenance perspective? Any major service that needs to be done other than Acura's regular scheduled transmission fluid servicing?

KenRLX

I have not heard of particular maintenence problems for the RLX SH.
I have heard the 'DONT MISS the fluid change intervals' on the maintenance minder.
And I have heard just how many thousands of bucks it costs to repair or replace the twin moter unit or the tranny.

There is an Acura TSB about shudder that inlcudes a tranny fluid change as well as a software update. I was told by the dealer that the recall about the 'odd gear software problem' also updates the software to deal with the shudder problem. I had that recall done, but they did not do a fluid change. After the 'odd gear software' update, the combination of the ICE and the electric motors seems smoother.

Legend2TL

+1, Professor Kelly's transmission video's are pretty amazing. The whole 7DCT was pretty interesting from a tech point of view, some I found unique.

1) the operation of the two wet clutches with the throwout bearings (made by German auto component makers Luk) that press to ENGAGE their respective clutch. Gotta wonder what the long term reliability of those two bearings are.
2) that 1st gear integrated into the planatary gearset with the Motor/Generator and how it can transmit power or receive power from EITHER countershaft.
3) kinda surprised the lubrication fluid was regular old Honda DW-1 ATF



yeah, this video was so good I had to repeat post it in the RLX and MDX section since figured many SH owners would be interested in how the DCT works.

jdpdata

I guess none of us have had the RLX/MDX Sport Hybrid for extended period of time to determine reliability of this 7DCT setup. My RLX only has about 5K miles so far. Been thinking maybe I should have dealer do fluid changes early for twin motor and SH tranny. It's only $99 ea. at my local Acura dealer for extra peace of mind. Overkill? Then do it again at 10K miles and every 30K miles after that. I doubt I would be drive that much being that I work from home and have no where to go in next 6 months due to lockdown.

mrgold35

Both my MDX/RLX did the "6" M.I.D. service for rear twin electric motors around the same mileage range. It was around 15,000 miles for the RLX and 17,000 miles for my MDX.. Not sure if it would help or hurt to change before the 15k mark since there is a break-in oil used for the rear diff. Assuming the same break-in DW-1 for the 7DCT? I will wait until M.I.D. transmission service pops up at 30k and then do a max of 30,000 miles for 7DCT and TMU after that.

RLX-Sport Hybrid

DO NOT MISS THE SERVICE INTERVAL ON THE DIFFERENTIAL AND THE TRANSMISSION!!!!!!!!!

Word to the wise.

mk5

This. I had a mystery grind/Moan/creak every time I would turn and sometimes just accelerate. Took it to the dealership multiple times. Never diagnosed proplerly. Then one day they tried changing the transmission fluid at a warranty service and THAT did it.

will never miss a transmission service