Guys, I will reiterate. There is no difference. I have extensive experience with torque converters (I swapped four different ones in the Camaro that I raced). I know when a converter is locked or not. Maybe it's a model year change, who knows, but on my 05 X the converter locks in MM.

 

That's what I want to hear, so I'll take your word for it.

Now I can stop slapping it back to D for fuel savings once cruising on the highway.

 

The TC will lock in 3rd, 4th, and 5th regardless of D or MM. As long as you're above the preset MPH and are cruising, it will lock. The thing about these TCs is that they're very responsive to throttle input and will unlock very quickly in relation to throttle input. The TC lock and unlock is very seamless too.

 

Yup, sensitive indeed. That function is controlled electronically. When I used the LS1 Edit program with the Camaro, I could adjust the sensitivity of the lock/unlock. In fact I ended up putting in a switch to force the converter to stay locked which I used at the end of the 1/4 mile run. Without it, the converter would never lock at WOT. It was good for a couple of mph.......

 

I noticed the same thing. Thought it was coming out of overdrive-There is a marked change even in drive when you apply just under a quarter throttle at highway speed-
Unless it's the timing suddenly advancing(hey you never know with these DBW setups)

 

At highway speeds, the rpms fall faster and more dramatically in MM mode than in D, when you let off the gas.

That suggests an unlocked, or at least an unlocking TC doesn't it?

 

Seeing some of the other replies after I had said that my '04 AWD 5AT TC didn't seem to lock up in MM got me to thinking that I should it try again.

Over the past couple of days I had the opportunity to do some uninterrupted highway cruising. What I found out is that below 70 mph, apparently the TC doesn't lock up in MM 5th.

The process I followed was to set the cruise speed just below 70 MPH in Drive, note the stabilized RPM, go into MM 4th and then upshift to 5th and wait for the RPMs to stabilize. It would always end up about 100 to 125 RPM higher than when in Drive. If I put it back into Drive from MM 5th, the RPM would drop about 100-125 and come back to where it was before I went into MM.

If I repeated the procedure at a cruise speed slightly above 70 MPH. the RPMs would be the same in both Drive and MM 5th.

This is probably what causes some of the confusion with different poster's experiences.

Seems like DaveB had the right idea.

 

is it possible to get that last G35x gear replaced with the G35 RWD/5AT 3.3 or lower? I wonder if it would be worth the cost. I thought I would be the one to be different, and fix my car as to get better mileage

 

well, I am still sticking to what I said. I dont know if it happens only at certain speeds though. I will try to do this at speeds of 60, 70 and 80 mph when I drive the car next. I believe the time I did it for my original post was at 70 mph. I will check the other speeds though. In the 05X though, in MM to definitely cruise around 200 rpms higher in the same gear than when in drive. This is just the amount of rpm difference that occurs when the TQ is unlocked/locked - which is why I said it. I have no "proof" that it is unlocked, but unless the G35 has a 4.5 dropdown gear or something that when in MM it goes too, I dont know anything else to attribute it too. I know it doesn't have this though, so that is why I am sticking to my statement. Dont know if this applies to any other year car or non AWD for that matter.

 

Be advised that if you change the rear ratio, you must also change the front ratio. Otherwise, very expensive noises will emanate therefrom!

 

how much $?

 

and for the record, the X can get outstanding mileage. I got 26.2 mpg at a 71mph cruise on my trip to Chicago from St Louis this last weekend. 320 miles, cruise set the entire time. When I got there, I still had a 1/3 of a tank of gas left - nav said I had 140 miles till empty remaining.

 

Sorry I have to disagree with your torque converter statement, true my car does down shift to 4th gear when I go into manual mode but when I bump it back into 5th gear my RPM's are exactly where they were when in auto D mode. or 3000 RPM's = 77 MPH