Cold shifting

[dannmarr]

Is this normal? When I leave from work, it is very cold outside. I get on the highway and it doesn't shift into the next gear until about a mile. After that it shifts fine from a stand still. This does not happen on warmer days or when I let it warm up for some time. My Mechanic says the Trans has a temperature sensor. Is this the case? I would like to know before I bring it back to the Trans shop. It's still under warranty.

[Wikedjuggalo]

Do you have a trans cooler?

[Blacky]

It should shift through all the gears but will only go into overdrive after it's warmed up.

[dannmarr]

Originally Posted by Blacky

It should shift through all the gears but will only go into overdrive after it's warmed up.

Yes, I have a trans cooler.
Overdrive is at what speed?
When I say it dosen't shift, I mean it reves high when I get on the highway, as if it's not shifting, then it kicks to normal RPM's, as if it goes into gear or (overdrive) once I drive it for about a mile. This ONLY happens on cold starts.

[WhatIsThisIDont]

IIRC, 4th gear is overdrive, and it won't shift into OD and lock the TC until the tranny fluid reaches a certain temperature.

That might explain the "only when cold" issue. Where does it rev around 55 mph when cold and when warm?

[dannmarr]

Originally Posted by WhatIsThisIDont

IIRC, 4th gear is overdrive, and it won't shift into OD and lock the TC until the tranny fluid reaches a certain temperature.

That might explain the "only when cold" issue. Where does it rev around 55 mph when cold and when warm?

Thanks! That sounds correct. A load off my mind!

[Sean486]

I use a cooler year round that bypasses the radiator. Mine does the same thing.

[Chucksta]

I don't know if all years have the same specs, but on mine, a 97, with 250,000 Km ( 150,000 miles ) , I get the following...

It shifts into 4th no matter how low the temperature, but it doesn't feel like overdrive until the torque converter locks up. The revs are higher due to slippage in the torque converter.

It will engage the lock up as low as 71 Km/h ( 44 Miles /Hr ) That's on a dead flat road with no acceleration for at least ten seconds. Lock up will disengage as road speed drops below 67 Km / h ( 41 Miles /H ).

It will not lock the torque converter until it's warmed up. The colder it is, the longer it takes. Starting from 0 F, it takes about 5 kilometers ( 3 miles ) , before it's warm enough to lock up.

It would also make a difference if the trans cooler has a thermostat in it. Some do, some don't. If you've by-passed the rad and have a non thermostatic cooler, it may take a bit longer to get the trans up to the temperature required.

[dannmarr]

I don't remember having this problem with the original Trans. I noticed this for the first time this winter after the 4.44 swap.

[Sean486]

My understanding is that it's more to do with the aftermarket cooler, especially if you bypass the radiator.

[Blacky]

Mine all do it with no cooler.

[Tapani]

With the OEM cooling set up my TCC lock engages and releases every 2-3 miles while cruising at 60 MPH, ambient temp -13C - -16C yesterday. I drove 250 miles and it did it continuously. The rad lower tank is just too cold for the fluid.

When the TCC is locked the revs are app 2250 and when released 2400 - 2500 rpm on a level surface. This with 3.7 gearing. I have to check the engage/release temps (JDM firmware).

I will install a stand alone cooler and a bypass thermostate when I find the time. As discussed before, the tranny overheats real easy on track days too :-) so there are two reasons for this.

/Tapani

[dannmarr]

I found an SVX article by Terry McLane on SVX-IW.com website:
"The 4-EAT will not shift into overdrive until the fluid reaches 50 degrees Fahrenheit."
Thanks to all!

[svxcess]

Actually, here is what he said on svx-iw.com:

4.4.4 - My car won't shift into 4th gear.

The 4-EAT will not shift into overdrive until the fluid reaches 50 degrees Fahrenheit. On very cold mornings in Wisconsin, don't be surprised if you have to drive awhile before it will shift into 4th.

I think he inadvertently dropped the "1". It should read 150 degrees Fahrenheit.


.

[Chucksta]

Hmmm .. 50 degrees .. or 150 degrees.. Quite a spread, to say the least.
my "spidey sense" started tingling, or maybe it was just my O.C.D... I knew I'd read 50 degrees fahrenheit somewhere, but couldn't remember where. So, it was, to see if I could find the correct reference. Suddenly, just as I was starting to.. SQUIRREL!!

Way more about the 4EAT than i wanted to know, but there's a kickin bit about how the " manual " button works in various shifter positions. All this time, I figured mine was broken, because when I pushed it, the light on the dash came on, but, it still started in first... Mainly because I hadn't put it in 2nd, or 3rd... and that the combination of manual button and shifter position changed the front to back power distribution when the manual button was pushed with the selector in first.

Read the second page of this...
http://www.northursalia.com/techdocs...ssion/4eat.pdf

Then there's this one, which, although it's for a phase 11 4EAT, ( next gen after the SVX ) gives a whack of info about the tranny, including that it still cuts the injector bandwith and retards timing on WOT shifts on models other than the SVX.. but that's a different story for a different thread , but on pg 29, it showed lock up temp requirement of 12 Celsius, which pretty much 50 fahrenheit. I doubt if the specs changed that much between the two gens.


http://www.xcceleration.com/trans/4E...ansmission.pdf

It would stand to reason that, in cold temps, a radiator by-passed thermostatic cooler would give the trans the quickest warm up, as the fluid wouldn't be traveling through the cold water in the rad before the engine thermostat started letting coolant enter the rad.

Maybe, if someone who lives in a southern state ( ie over 50 when they "cold start" ), has noticed torque converter lock up pretty much off the get go, they could post..