Quick question for you guys. On a flat road and "normal" i.e "granny" acceleration my transmission shift to 5th gear around 47mph. Is this what you guys see as well?

 

 

So 47mph is normal. OK thanks, I guess I'm use to my other vehicles which go into 5th O/D around 40mph.

 

Yes sir. As long as it's not holding at 3rd gear at ~47 mph

 

I was weirded out but the shift point on my TL to, seems like it goes to the highest gear pretty quick, but i do drive like a granny much!

 

Would switching redline/amsoil ATF have any affect on shift points?

 

What's the deal with the 3rd gear?

 

I believe that he is referring to the p/s switches that start to fail on 3G's.

 

No.

 

 

Just speaking for me, but changing to Redline D4 completely changed the shift points on my transmission. Before the change it was holding a couple of the gears too long (included was the 3rd gear mentioned above). It's much better after the change.

 

Forgot to mention, it also fixed my 3rd gear shudder.

 

I concede this point. If a person's previous ATF was Z1 (fresh or dogged-out), the shift points may or may not change when switching to racing ATF. I have no experience.

I have never had "old" ATF fluid in my TL since it was new. I started doing regular ATF changes every 3000 miles since the odometer was 14,700. I had always used Mobil 1 Synthetic ATF Multi-Vehicle until I switched to Redline Racing ATF.

My shift points did Not change between the fresh Mobil 1 Synthetic ATF Multi-Vehicle and the Redline Racing ATF.

 

Decided to try redline d4 today. Local shop here in Albuquerque has it here for $10.50/qrt, so I bought 3qrts to do a 1X3 and see if it has any affect on shift points. First impressions is that it appears to improve shift "quality" but it does not affect shift points. BTW, I did a 3X3 flush with Z1 about 10k miles ago so the ATF that was in the tranny was relatively fresh. Anyways, I will complete the 3X3 flush over the course of the next couple of weeks and also replace the 3rd/4th gear switches.

 

So do you remember at what speed 5th gear would kick in before, and at what speed does it kick in now?

 

The ECU and the ECU alone controls shift points.

Going from crappy Z1 to Redline can make it feel like it changed the shift points but it doesn't actually change it.

The ECU sends the signal to the shift solenoids to make the change and the hydraulic circuit is energized. The shift will begin at the exact same time but it will take longer to complete with the Z1 fluid. Unless there was an issue with something plugged up with the Z1 which the Redline cleaned out, a fluid can't change shift points.

As for the programmed shift points, most OEMs go for fuel economy above all else. Low rpms and higher load will produce better mpg.

There are a ton of factors for determining shift points with the big ones being engine powerband, weight, final drive ratio, and throttle position. The TL is a high revving V6 without a whole lot of low end torque so it won't pull cleanly from 1,500rpm like a V8 will.

Oveall ratio is what matters here. The TL's 5th gear may be taller than another vehicle's 5th gear so it would require more vehicle speed before making the shift. Or in other words, look at gear ratio, not which gear it's in.

 

Well, I will accept IHC's word as gospel here as I can't even begin to scrape the surface of what I feel he knows about the tranny on this car. So if he says it doesn't change shift points I believe it, although it did make that much of a difference where it feels like it did. BTW, thanks IHC for all your input on the fluid and sensors. I feel after making changes based on yours and others knowledge, that I will actually be able to drive this car much much longer without any major work. Great news after a bad tranny experience with a Audi A4. Needless to say I'll never consider another Audi.

 

I should have stated my post a little differently. While the ECU controls shift points.... and the Z1 can make the shift take longer from beginning to end even though they will begin at the same time.....the actual completed shift on Z1 can be later than Redline. So in effect, you are right that the shift points were changed even though the ECU commands the shifts at the same time.

Thanks for the thanks lol.

BTW, I think the "holding of the gear too long" was the Z1 causing slippage. I still can't believe Honda deemed this fluid acceptable.

 

PCM controls shift points but those shift points are also determined by sensor feedback correct? Sensors like pedal position, speed sensor, p/s etc., determine when to shift up/down so a bad sensor can cause the PCM to shift the tranny at the wrong point. Then it makes you wonder since hydraulic pressure shouldn't change from Z1 to D4 the p/s will see the same pressure or does it. Is there any possibility that the pressure is different or is it just a matter of FM, viscosity etc. that causes people to think that the shift points are actually changing.

 

Viscosity can make a difference in hydraulic pressure but the system is regulated to the same pressure regardless of viscosity. Think about this, D4 and Z1 both have a viscosity of around 7cSt at 212 degrees. At 50 degrees they're over 150cSt. Obviously viscosity, especially a small hot viscosity change will have no effect on shift points.

I think the lack of FM and the corresponding quick shifts with the good fluid causes the perception of lower shift points even though the shift is commanded at the same time.

The commonly replaced 3rd and 4th gear pressure switches have been shown to affect shift timing.

 

Good info thanks. So regardless of ATF the PCM will have the same shift points it just appears to shift faster since the actual shift is completed sooner. So electronically no change, but mechanically it occurs sooner. Ok makes sense and not trying to beat a dead horse here, but replacing the pressure switches will have an effect on shift points right?

 

Yep. We had one of our electrical guys on this forum (an EE, I think) measure resistance values of new vs old (bad) switches and it was shown the the values of 3rd gear switch overlapped the 4th gear sensor range causing all kinds of havoc which is why these things cause trans failures. These things tell the ECU when to make the shift so to say the least they were confusing the ECU. I'll look it up in the morning. Pretty interesting stuff.

 

Looking forward to it. Thanks again.

 

So I'm in the market for a TL are there problems with these transmissions? Something the dealer makes sure is fixed before i purchase? I know when dealing with the legend Honda ATF was all people put in their legend. They don't use Honda ATF anymore in the TL tranies?

 

Honda ATF is what Honda says to use. Honda ATF is also part of what has been causing all of the failures. Switching to a good type F fluid and replacing the pressure switches at regular intervals will nearly eliminate failures.

 

Wow that's wild! What is the ATF by Honda now is it another cheap company making it maybe? How often do these pressure switches need changing? Are 07/08 trans in these cars the best with the kinks gone?

 

The kinks were pretty much gone in '05. '04 models had to have the oil jet kit installed due to lack of lube on the 2nd gear countershaft.

'07-'08 do have a better transmission but that's more of an upgrade and not to fix any issues with the '05 and '06 units.

The earlier ones are bulletproof with the type f fluid and switches though. I have countless track days on mine and it's about to hit 100,000 miles. "Bert" on here has well over 100,000 on his and he's pushing double the facotry hp and torque.

I would honestly do the switches every 3 years or 50,000 miles. From tracking the failure history on here, the failures seem to be just as time related as mileage related if not more time related. It kind of sucks to do these things every 3 years but they will save you $3,500 down the road and they can be done without jacking the car up and only cost $90.

The Honda ATF has always been bad. Honda chose to load it up with friction modifiers to produce super soft shifts at the expense of wear. What ended up happening is the shifts got so soft that these cars developed a "bump shift" from too much FM. Replacing the Honda fluid with a type F fluid pretty much stops wear in the clutches and due to the bumpshift, it improves shift quality too.

 

I take it the switches are under hood ? Is there a link to show the process of changing these switches ?

I just did a 3x3 redline ATF change.

 

Ah very cool! Thanks my man.

 

Use the Search function, I know I'm new here but I did tons of research before ever making my first post. Most everything your looking for is here, esp transmission info. Take a look in the 3G garage.