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4EAT won't shift out of first - install a switch to make it shift?


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when first started my XT6 will shift fine. after about 10 minutes or so of driving or being turned on it won't shift out of first gear. why not?

 

if it does go into gear, it operates fine, no slippage at all and plenty of power. fluid level is fine, i changed the fluid and the lights on the parking selector show up just fine. when it is first started it will shift through all the gears fine as well so i don't think it's linkage related.

 

can i "hard wire it" and force it to shift into a higher gear? i'm pulling this transmission sometime soon anyway but would like some functionality for now if i can switch it into gear myself....i'm sure it's complicated....???

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being that the XT6 is a bit of a cross over with the 4EAT, which is mostly an EJ transmission i was hoping the mod's would let me cross post here since i know there are some really knowledgeable 4EAT folks on the New Gen side.

 

my 4EAT (XT6 - which is easily swappable to an EJ trans, very similar). after warming up it won't shift out of first, but otherwise works fine in any gear with no slipping, new fluid, indicator lights are fine and i believe the linkage is fine. any comments:

 

http://www.ultimatesubaru.org/forum/showthread.php?p=685448#post685448

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What happens if you start off in D2 ?

 

What happens if you (i hate asking) rev it out, does it force an upshift?

 

Do you have reverse?

 

My first guess would be its not getting a speed signal (govenor in older trannies, VSS in newer).

 

nipper

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i'm not sure what you're asking, it does not shift out of first (no matter what..gear, rpm's, restarting, etc). when i first start it in the morning (cold) it shifts fine. after it warms up, no go.

 

My first guess would be its not getting a speed signal (govenor in older trannies, VSS in newer).
the front speed sensor has been inoperable for a year so i don't think that is it. and i drove another XT6 for a year before without the speed sensor hooked up before as well, so i don't think that is it. but i will check the rear wheel speed sensor, maybe that combined with the front not working is causing something. that would be sweet if it was that simple....
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why oh why do i have to bring bad news....

 

 

its either the seals or the front pump. Only way of truly knowing is with a set of pressure gauges on the tranny. When the tranny is cold, everything is tight, and the fluid is thick. You get enough pressure to engage things (the tranny is slipping a bit but you cant feel it). As everything warms up, fluid thins out, seals get soft, you loose pressure. At this point tray an additive and a fluid change to see if it helps.

 

If it was just a bad VSS, as the engine got to redline, the tranny would force an upshift no matter what if it was healthy.

 

Start off in D2 after you loose all the upper gears. This wil start you off in 2nd gear, see what happens. Then if that works, try shifing to d3 or D whichever one you have next.

 

 

nipper

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"..i'm sure it's complicated....???"

 

I built the tranny shift solenoid monitor

used cuurently in one of my 4EATs

benchlit.JPG

 

Seen here in detail

4EAT monitor

 

Yes the shift algorithm is complicated

it could be your line pressure is falling

and thus no shift from first.

 

You might try wiring a similar device to watch the output

from the TCU.

 

This would narrow down the problem to the tranny or the TCU.

 

One guess is the line pressure is not making the trip when warm.

 

The TPS may also have the idle switch stuck on

this may prevent the TCU from letting it shift.

 

As it could be either the tranny not shifting or the TCU not telling it to shift,

I would try and narrow it down to which is at fault.

 

 

Doesn't the XT6 have some switch on the console to keep it in the lower gears?

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yes skip the XT6 has a first hold switch, i don't think that's the problem. that box you have is mighty fantastic but probably beyond my scope to make and properly hook up. i'll look into it.

 

good point on the TPS - i'll check the contacts, wiring and swap in another one. unfortunately the XT6 FSM is dead wrong on TPS spec's so i can't really test it, though the idle switch should be straight forward open/closed.

 

funny thing...before this my transmission was not going into drive (AT ALL) until it warmed up. in other words if i put it in any gear it would just stall...like putting a manual trans in gear with the brakes on...just stall out immediately without moving. after it warmed up for a few minutes it would drive completely normal and would not do that again until left to cool for a long time....hmmm...i bet it's related.

 

since both are issues related to "being warmed up"...i wonder if it is pointing to the idle switch...but not sure why it would have two different symptoms like this.

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Skip was wondering if the TPS idle switch is cracked up?

 

Just before it was doing this it had a problem that was a bit different (but i bet related). The trans would not go into drive until it was warmed (kind of the opposite of now). I would have to let the car warm up for 10 minutes and then it would drive perfectly fine...highways, towing, mountains, etc. If i tried to drive when i first started it, it would stall as soon as i put it in gear...like a manual trans put into gear with the brakes on.

 

i was replacing it anyway and already have a legacy 4EAT ready to go in it....but wasn't planning on that for a couple months.

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not sure. it would just die almost instantaneously like it hit a brick wall...basically just like a manual transmission that is put in gear with the ebrake on...dead stall, no sputter. if i reved it really high rpm in neutral then slammed it into drive it would rock a foot or something and then die...but no sputtering at all, it would just stall like it wasn't engaging at all.

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what would it do if i forced it into 2nd, 3rd, or 4th...since it shifts and drives fine when it does choose to go there i'm finding it hard to believe it wouldn't drive fine...at least for a little while! i find it goofy and outright stupid that it just won't shift when it's at 6 or 7,000 rpms. how is that better than shifting into gear and slipping some?

 

i've had and been in slipping auto trans before and mine does not slip a bit, shifts great...(if it shifts!)

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seems goofy that it would rather run the engine at 5,000, 6,000 or 7,000 rpm than just shift into 2nd or 3rd even if it isn't working perfectly. TCU designers: "if the transmission is going out, let's make sure it takes the engine with it??" guess that comes down to how i drive it, but still goofy.

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nope. thats a fail safe, thinking that the operator of the car SHOULD notice that something is wrong and stop driving. There has to be some common sense to driving and education. That forced upshift is mechanical and has been there as long as there have been auto transmissions. Its for when the govenor/road speed input fails, or the nut behind the wheel keeps the car in low.

 

Remember you dont have any line pressure, and thats what makes everything work. Give it another week or so, and it wont move at all.

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what would it do if i forced it into 2nd, 3rd, or 4th...since it shifts and drives fine when it does choose to go there i'm finding it hard to believe it wouldn't drive fine...at least for a little while! i find it goofy and outright stupid that it just won't shift when it's at 6 or 7,000 rpms. how is that better than shifting into gear and slipping some?

 

i've had and been in slipping auto trans before and mine does not slip a bit, shifts great...(if it shifts!)

 

thats sort of like "the brakes are fine as long as i dont leave the driveway". Only reason its not slipping is because it cant make enough pressure to grab any clutches after it warms up.

 

This is a mechanical failure, where the car should not be driven at all.

 

 

Come out of denial, its safe, its ok :clap:

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Since this is an electronic tranny, I say it would be

a waste to right it off for

a TCU or it's inputs problem.

 

Guess you will find out when you swap the tranny.

 

Why not wire just one LED to the second gear shift solenoid,

 

if it lights and does not shift.. well

nuff said.

 

I am absolutly sure

you and Nipper will hash it out.

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Since this is an electronic tranny, I say it would be

a waste to right it off for

a TCU or it's inputs problem.

 

Guess you will find out when you swap the tranny.

 

Why not wire just one LED to the second gear shift solenoid,

 

if it lights and does not shift.. well

nuff said.

 

I am absolutly sure

you and Nipper will hash it out.

 

Skip we have, and hes deep in denial :grin:

 

hehehe

 

nipper

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Is a 4EAT different than the automatic transmissions that I know of? In the ones I'm familiar with, reverse requires the highest pressure of any gear to engage. So, in circumstances like these, if it would still engage reverse and move one would not diagnose low pressure/bad pump/bad seals. Are these designed differently?

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