I hate cars

The racing fluid is a little thicker at operating temp (212F). But since it's a good synthetic it's probably not going to be much if any thicker on a cold winter start. That's one of the advantages of synthetics, good cold flow.

If you're concerned, you can do one or two drains and fills with the lightweight fluid. They're the same (type F) but with different viscosities.

I know it's scary putting a non recommended fluid in such an expensive trans, especially one with a higher viscosity. But even the terrible Z1 works ok in everything from Alaskan climates to Vegas summers. To put it in perspective, the 10cSt Redline at 212F will be the same viscosity as 7cSt Z1 at 190F. Viscosity only really matters in temperature extremes. It's more than 20x thicker at startup than at operating temp. Driving down the freeway at 65mph, the Z1 will be the same viscosity as Redline during city driving.

jsonkimz

iTrader: (1)

I don't really know what any of that means as far as viscosity, but I did pick up that it'll be fine, and I feel good with going with your recommendation. I'm not going to worry about it. Thanks!

I hate cars

Basically yes. If you're worried about it being too thick, order some of the "lightweight racing" fluid for one of the drain and fills and it will be no thicker than the stock fluid. You'll be fine with whatever you go with.

Mindworm

Gents -

Just wanted to say "thanks". I was sure I was going to need a new tranny, and came here to read up before I dropped the $$$. Glad I did. 2 sensors, a change in fluid, and she's running pretty smooth. Very glad I still lurk around these parts...

2004 Anthracite with black interior, always been a bit rattle-y, with 122,000 miles, a faded dash, but leather that still looks and feels great. Still get close to 30 mpg on the highway when going 70-80 most of the time. New tranny at 49,500 (right before warranty expired!) on it, for those of you playing at home. Other than that, it's been regular maintenance. Nice!

upnout

iTrader: (6)

Just ordered my parts for the tranny, (filter and switches) 102K and counting

dwb993

iTrader: (13)

I've done both of these on my 06. Let me know if you need help, Mike.

jhumbo

iTrader: (1)

Exactly my sentiments. Been running on new sensors and fluid for the past couple months and the tranny has felt good. Thanks!

Soonermagic

If the sensors were crapping out....the check engine light would display. So what is the likelihood that folks are prematurely changing these out?

I hate cars

Nope. They will not set a check engine light unless they're way out of parameter such as an open or a short. Anything in between an outright failure will not set a light. The difference is night and day.

jhumbo

iTrader: (1)

Confirmed. Mine were crapping out (at 110k) and no check engine light. Felt shudder as the tranny had trouble with the 3rd to 4th shift. Swapped out the sensors and haven't felt it since.

swoosh

iTrader: (5)

dont get me wrong here but what about people who use the SS mode in shifting all the time(me for example).....i would not need this since my shifts dont depend on the pressure sensors....they depend on my driving.....i can shift from 3rd to 4th ar 2K rpm or at 6K rpm....the pressure sensor would be bypassed......

i have changed them out as a preventive maintenance but i dont think i needed to.....in 60K out of the 70K miles on my car, put by me, i have used SS shifting.....

I hate cars

They are used in auto mode and manual mode. Switches don't determine when it shifts, they determine how hard and quick it shifts. They are still very much needed in manual mode.

Sanyin

Just changed the 3rd/4th switches, shifting is definitely better. The time between clutch release and next one engaging is a lot shorter, if at all noticeable. Very quick and smooth, im happy.

So yea, works on 2000 TL.

Thanks a lot for the info.

mb1976

Thanks I Hate Cars for posting this information I am planning on doing the switches either on my next oil change or at 75k

jwsilvey

Just changed out my ATF. The tranny feels a lot better than before. So far the shuddering is gone. I have also changed out the pressure switchs.

IHC, i only did a 1x3. How long should I wait until I do another? i want to get rid of the Z1 that is in there.

Steve5.9

Wow! What a difference! I installed the new sensors earlier today and all the shaking and shuddering is gone. It's hard to imagine that something that took less than an hour can make so much difference. This thing shifts like a new car! Thanks again everybody for the posts and for the DIY!

Cheers,

Steve

Mkarl

I finally tested and compared old and new pressure sensors.

Spec - 3rd P-switch 33psi - on
Spec - 4th P-switch 27psi - on

Sensor . ON ... OFF - PSI
Old ...... 37 ..... 31
New .... 33 ..... 23 .... Spec - on = 33

Old ...... 31 ..... 25
New .... 26 ..... 17 ..... Spec - on = 27

The old 4th P-switch is almost at the 3rd switch value.
Both have half the New switch "on to off" PSI spread.

The Sensor has a membrane sealing the oil from the switch assembly.
The switch comprises a small flexed disk that sits against the membrane.
When oil pressure is applied against the membrane it flexes the disk.
The disk pops in at the design pressure thereby completing the circuit between the casing and the centre contact.

This is not a sophisticated design when compared to some units used in late industrial applications however those can cost upwards of $500 a unit.



The pictures show both sides of the flex disk and the flex disk installed. -

I hate cars

Thank you for this info! I'm glad we have numbers to go by instead of just feelings.

Majofo

Bravo Mkarl.. How many miles were on those P Switches?

08TLEE

Have you checked out the TSB's in the 3rd-gen TL "General" area? There is one on the faded dash issue, it's basically some conditioners or something that come to the surface. The TSB recommends a product...NOT the "official" Acura dash-cleaning product...that supposedly will make it good as new. I haven't had a chance to try it yet myself.

Inaccurate

Thank you Mkarl

This reminds me of the show "Sliced" on the History Channel.

Mkarl

IHC, Majofo and Inaccurate. Hi all, I hope this post is not too long or off topic because of the Accord.

The car has 78,000 miles and is 2004 G7 V6-5AT Accord – The transmission used ran 2003 to 2006 in these models with the early versions needing an oil jet mod recall - extra clutch in the 3rd gear pack in 2006 and minor mods along the way?

The P-Switches solved three problems/ annoyances.

1. When cold the engagement from N to D was around 1 second. If you stepped on the gas after the first bump but before the second it could grab 1st a bit hard.

The double bump feeling: When you change from N to D (V6 only) the PCM engages the 3rd gear clutch before it engages 1st (after release of 3rd) to lessen the engagement shock I guess? I think the transmission was being forced to wait longer for the required 3rd gear pressure to be indicated by the pressure switch before releasing and sliding into 1st. I think reduced pressure as a transmission ages may be a common condition and these witches, as they age, may be forcing the transmission to build even more pressure?

After the P-switch change, the transmission will not grab even if you get on the gas after the first bump. I feel the old P-switch allowed the RPM to go higher (build pressure) before quickly selecting 1st with the higher RPM, now it’s smooth and quick. The N-P engagement time is now less than ˝ second.

2. I noticed a change in the way 4th responds at speeds below 40mph. Prior to changing 3rd and 4th P-switches, 3rd to 4th shifts were difficult to feel and 4th shifted through quite quickly, now it holds longer in 4th and the change into 4th is crisp and noticeable. To recap – All shifts into and through all gears now have a consistent feel. These changes are things that some drivers may not really notice and I keep forgetting to clarify this when I post.

3. The manual gives a vague outline of changes in shift feel and RPM shift points when discussing cold versus warm operation however, I felt the throttle (DBW) was still being held back a little too much on 2-3 shifts, especially cold, as it was slightly different to 1-2 and 3-4 cold shifts and I noticed it. Since the P-switch change I feel these are back to what I expected from both cold and warm trans oil and engine temperature operation.

Finally, the workshop manual glosses over the P-switches but, a reference to them reads – “Pressure switches 3 and 4 - Correction of hydraulic pressure and application timing”

The pressure switches are included in a list of possible causes for – “Excessive shock or flares on 2-3 up-shifts or 3-2 downshifts and 3-4 up-shifts or 4-3 downshifts”. This appears to do with a P-switch orifice being blocked. The TCU can generate codes P0847/48 and P0872/73 for the P-switches being stuck on/off (and D Indicator blinks) therefore I assume a partial blockage is being referred to here? This raises the question again as to what effect “sensor ageing” has on clutch life as the sensors drift up or down from the rated trip PSI but, not enough to set a code.

Mkarl

I wanted to add one more thought. I believe from the way the shifts have changes that the P-switches are also used to indicate when “clutch pressure” has “bleed down” and is used to time overlap in and out of 3rd and 4th. I feel this makes those release PSI values and on-off transition spread PSI values really important.

I hate cars

This is great info. It explains how the switches can control shift firmness and timing.

I noticed a huge difference in cold trans performance and downshifts, probably moreso than normal hot operation.

It's really good to know what the double bump is. I thought it might be hitting second and then first but it's good to know that it's actually third and that the switches can help it.

Inaccurate

Mkarl,

Will you be trying the RedLine Racing fluid? What ATF have you been using?

Thank you for sharing your technical insight

I hate cars

Think about where we were just two years ago. "Don't use anything but Z1 or your trans will blow up". I practically got run out of bitog (actually I am permanently banned) for suggesting type F fluid in a Honda lol. "It's the death shudder, time to replace the trans". Just a couple of years ago, shudder was the end of the trans life and you were stuck with Z1.

Thanks to both of you. Inaccurate for having the nerve to put his "money" where his mouth was and use the Type F. I knew it wouldn't hurt but I figured there would be at some point a percentage of Type F that would cause at a minimum TCC shudder. I'm glad I was wrong.

Mkarl

Inaccurate, IHC. I am currently running Redline D4 a big transmission cooler and a Magnefine filter instead of the case mounted OEM filter.

I have been trying to find a source of the Racing fluid over here in AU – sent an email to the Redline distributor and still no reply.

In AU, “Dinosaur urine” - Z1 is priced at $53.00 for 4L; Redline D4 is $148.00 for a 3.9L container %#$*. Managed to get D4 at a reduced price but still expensive.

I going to do the rounds of the Speed shops and Hi performance transmission builders, surely someone uses it here?

TheChamp531

iTrader: (3)

Best place would be eBay. Pack of 12 QUARTS (~11ish Liters) is $135 + shipping. I'd say it would cost about $40-50 to ship it too Australia could be a lot more though. You would still save money.

Mkarl

Just received a reply from Redline AU – 18.92Ltr $450.00 including tax and shipping and will only ship that amount. That price has come down; it was $640.00 a few months back – current exchange rate helps.
I know from past experience that any large or slightly heavy item is costly to import – anyway I will make some enquiries.

I hate cars

Would it help if you had someone from the US ship it over to you?

Steve5.9

F word!

After a few days of driving it around the shaking is back!!! I've done the flush and fill and recently I changed the sensors, now what? Maybe I'm I just need a new transmission I got 97k miles (out of warranty) on this one and never had any tranny probs til now.

Mkarl

Steve, just out of interest did you reset the ECU-TCU when you changed the oil and Sensors.

Reason I ask is these dam things seem to be programmed to make shifting as “slush box smooth” as possible. If you have a dodgy clutch pack then as the engagement (lockup up) is slowed it may cause shudder. After a reset the TCU-ECU appears to shorten the engagement times until it re-calibrates and goes back to what I call crap-shifting, usually within a few days. If the clutch pack locked quickly (after the reset) it may have temporarily masked the problem. Mike

Mkarl

Hi IHC, I sent you a PM with a question and a little off topic info.

wantboost

R these auto trans prone to failure how many r rebuilding there's already?

justen

Wow, just spent the last 2 days reading thru this and i ordered the sensors and washers, looking fwd to getting rid of the shudder, hopefully its not too late, it started about 10k ago and im at 144k now. only does it under slow accerlation right before 2k rpm's so ive just been driving it hard at slow speeds to prevent it. I have noticed the feeling like your brakes got jammed on when slowing down from highway speeds and it really bothers me more than the shudder, i hope the sensors resolve that as well. also need to look into the ATF filter, seems like its worth doing since its in a reachable location and its only 10 bucks, ill let u know it then sensors fix the shiting issues when they come in, ordered them from delray.

Steve5.9

I reset it this morning and the shuddering is gone, but I think that is because the gears are shifting at ~2500 RPMs and it never shuddered at that RPM. I'm doing a 3x3 this weekend with Redline ATF so I'll update then. Thanks

Mkarl

I listed the old/new sensor values I measured a few posts back, anyway, had a few spare minutes and made a quick graphic.
Maybe of no interest but what the hell, so here it is.

justen

Did the swap today and its shifting much better. thanks for the DIY it was really easy

spineman

OK. My eyes are bleeding reading thru the whole thread. I just bought a 05 w 54k after my 2000 tl blew thru 3 trannies ( always changed with honda atf...wtf). Don't know why I bought another one...but I love Hondas. I have owned a car lot of them first being a 81 civic. Anyhoo So I am under warranty for another year or so. In summary:

1. I believe I will change ATF to Redline now 3x3

2. Change sensors (will the dealer ever do this under warranty?) Having hard shift from 1 to 2 No prob with 3 to 4

3. I guess my real question is what actually do I ask or tell the dealer?

Any other advice for a newbie to the 3G would be great. Honda silicone awesome for creaks and squeaks so far!

danmm7

iTrader: (1)

I am just curious... would this be a good idea on the 5-speed AT installed on the 2006 RL?

I know the RL is AWD and all .... but, how similar/different are the two Auto transmissions? Does the RL have the same problematic sensors?


Thanks!