Interesting...

There is another thread discussing transmission "slip" and "jerk". In it, torque converter lock-up is mentioned, and seems like a reasonable explanation for what is described; I thought all cars these days have a lock-up torque converter.

However, my car never seems to lock (unless it is so subtle as it is undetectable), and seems to have a great deal of "slip". In other words, it feels like a very "loose", hi performance converter all the way through the rev range. For example, if I'm at steady state in a gear, doubling the engine speed under full acceleration doesn't give double the speed.

I mentioned it to the service writer, and he gave me all of the expected answers: 1) the car doesn't have a lock-up converter, 2) it is perfectly normal, 3) they all do that, and 4) it will still be learning until 5,000 miles.

???

 

not much help...

but i agree.

however my times are under 6 sec with the auto...

ppp

 

Yes,

Now that I've gotten a few miles on the car, it seems to perform fine, and I don't feel any of the tell-tale signs of a failing tranny (slipping and then lurching forward, shuddering, etc.), so I'm not in panic mode. It just doesn't seem to "lock" like most other modern autos I've driven. I'll keep an eye on it, and give them the benefit of the doubt.


Tony

 

Our trannies do have a lock-up converter and it engages almost imperseptibly after complete warmup.-
Try this: after warm up, and from a stop, try accelerating moderately and counting the gear changes. You'll feel the normal 2 thru 5 changes and then a similar change into lockup at which time the rpms drop modestly.
You can also notice the lockup after shifting into Manual mode at speed (say 60 mph) which engages 4th non lockup , then changes into 4th lockup.

I've read, too, that the lockup engages in lower gears, I believe from 3rd to 5th gears!

If you're worried about a faulty tranny, check the fluid colour regularly, for it's customary light pink tone. (as well as being up to level).
If it darkens, it's a sign of problems.
Some trannies don't have the dipstick to do this. The dealer has the proper equipment in this case.

C.

 

Adendum:

I just checked the ESM and it explains that the lockup occurs in the top 2 gears only. Not in 3rd as I thought.

Colin.

 

Thanks for the info.

I'll try those tests tomorrow (drove the old car today; last few times before returning it to stock and turning it in).

Tony

 

gsedanman said " I just checked the ESM and it explains that the lockup occurs in the top 2 gears only. Not in 3rd as I thought. "

Ah ha. That sounds like documented proof we DO have a locking converter.

I have seen 2 different reviews of the G35 that said we don't. Or rather, it was a list of specs that had a NO next to the Locking Torque Converter spec.

Also, I tried ALL the different driving tests to prove my converter DID in fact lock, but it just never did what you guys said it was supposed to do. 4th gear at 60 and never feel it lock or unlock. cruising at 60 in 4th and give it a little (or a lot) of gas, and see it unlock, etc. I NEVER saw or felt the converter lock or unlock.

But, now at last, I have some proof.

I get 24.03 MPG highway in my '04 X, so I never thought there was anything wrong. Just wanted to know.

 

Taken straight from the JATCO, the makers of the JR507E 5 speed automatic in your G:

Here's the link http://www.jatco.co.jp/E_JATCO/PLAZA...nglish/no3.htm

I'd run, not walk, from any Infiniti dealership that tells you your G doesn't have a lock-up torque converter.

 

OK,

I've had a chance to test this more completely now, and I still see no signs of converter lock-up. At highway speeds, I've shifted into manual, and the car goes into 4th gear, but doesn't locks after a few seconds of steady-state cruising. I can upshift into 5th, but same thing, still no lock.

In normal automatic acceleration, I can detect the 4 shifts up into 5th gear, but never a lock-up.

When I told him that I didn't sense a lock-up, and that shifts seemed rather soft to me, the service writer said was that everything checked out normally, and the transmission "learns" for 5,000 miles, so it's behavior won't be normal until then. I suspect that this was just a stalling technique; it gets me out of his hair until 5,000 miles .

Comments? I know the tranny is adaptive, but the learning process isn't really that long is it? And I should be seeing the lock-up even with 3,000 miles on the car, correct?

 

I believe its just imperceptable to you. I can't feel mine lock up but it probably does and I don't stress about it.

 

Do this test. At 75mph and in D (5th), push the throttle a little bit and accelerate from 75-85mph at a gradual pace. The car should accelerate and the rpms should slowly rise. Now do the same test, but this time give it a bit more gas, but not enough to force a downshift. This time the rpms should immediately jump 300-400rpms, but the rpms won't rise after that initial jump, and the car will accelerate more strongly. The immediate jump in rpms is the torque converter becoming unlocked and doing it's job of fluid torque multiplication.

 

Thanks DaveB,

I'll give that a try on the way home, and post what happens.

Maybe (hopefully) as EZZ guesses, it just is so subtle that I'm not feeling it.



Tony

 

Hello again,

I took a 100 mile road trip yesterday, so I got a chance to sort out my tranny dilemma...

I used 4th and 5th in manual mode to keep from clouding the issue with downshifts, and was finally able to see the lockup. First off, I should say that it is totally imperceptible in my car. When I select a gear, and for relatively long time after (about 10 seconds), the converter doesn't lock; I can floor it and see large RPM swings.

If i maintain a realatively constant speed for more than 10 seconds or so and THEN floor it, I only get 1 or 200 RPM swings, so it has obviously locked. Odd that it takes so long, but it it does eventually lock.

So, thanks for the help, and for the others of you who questioned it, give this a try.


Tony