NorthWet Posted November 12, 2008 Share Posted November 12, 2008 I have a 92 SVX where the 4EAT tranny seems to disconnect/freewheel/no-longer-transmits-power when the tach hits approximately 3100rpm. Throttle position does not seem to matter; neither does gear, road speed, load, accelerating, coasting, decelerating/overrun. The only factor that seems to matter is RPM. As soon as the engine drops below the critical RPM the tranny hooks up as if nothing happened. There was no blinking "power" light until recently (have to find the procedure to pull codes). Tranny was severely abused by PO, still getting "mud" when I do ATF flushes, so it has plenty of other quirks that I have seen before... but not this one. Anybody know what the tranny does differently around 3000-3200rpm? Link to comment Share on other sites More sharing options...
NorthWet Posted November 13, 2008 Author Share Posted November 13, 2008 i actually think your in limp mode. Engine power will be capped at a specific RPM/Speed. You need to look deeper into this. nipper Seems unlikely that engine is in limp mode. Engine revs freely past redline if I am inattentive and just mash the throttle (acceleration to 3100 rpm, then tranny "disconnects" and tach needle swings towards the red end of the tach). Tranny acts like it slips into neutral above the critical rpm. Link to comment Share on other sites More sharing options...
NorthWet Posted November 13, 2008 Author Share Posted November 13, 2008 Ewwwwwwwwwwwwwwwwww You need a transmission. You have dreaded SVX tranmission failure. High gear is gone. The clutches are slipping. nipper All gears function. Strong engagement on each (though I think that there is some drag on the forward/reverse component (Band? That is what it is in the 3AT) causing a slight-but continuous forward engagement. Disengagement occurs in all forward gears. (Haven't tried running it up to 3100+ in reverse...yet ) Generally, I agree that the tranny has problems and should be replaced/rebuilt, but would like to limp until the rain and mud stops. Really tough to drive an SVX like a Yugo... especially when the end of my little road dumps into a 50MPH highway. Link to comment Share on other sites More sharing options...
NorthWet Posted November 14, 2008 Author Share Posted November 14, 2008 The problem occurs in all forward gears (as prev stated, haven't tried 3100+ in Reverse). Very consistent that it occurs at 3100rpm, regardless of other factors, even going downhill in second during engine braking. Something sems to be occurring in the hydraulics at 3100-ishRPM, something that the valve-body/control-electronics is telling the tranny to do differently at that point. I can't see a merely mechanical wear condition producing such consistent results under all regimes of driving with only RPM being the (apparent) common denominator. Link to comment Share on other sites More sharing options...
keltik Posted November 14, 2008 Share Posted November 14, 2008 torque converter lockup working ok? Cant think of much else that would happen around that rpm Sounds like a loss of line pressure as soon as the trans opens whatever solenoid.....but im no expert Link to comment Share on other sites More sharing options...
Hondasucks Posted November 14, 2008 Share Posted November 14, 2008 I have a 92 SVX where the 4EAT tranny seems to disconnect/freewheel/no-longer-transmits-power when the tach hits approximately 3100rpm. Throttle position does not seem to matter; neither does gear, road speed, load, accelerating, coasting, decelerating/overrun. The only factor that seems to matter is RPM. As soon as the engine drops below the critical RPM the tranny hooks up as if nothing happened. There was no blinking "power" light until recently (have to find the procedure to pull codes). Tranny was severely abused by PO, still getting "mud" when I do ATF flushes, so it has plenty of other quirks that I have seen before... but not this one. Anybody know what the tranny does differently around 3000-3200rpm? Have you tried posting this over on the SVX forum? http://www.subaru-svx.net Link to comment Share on other sites More sharing options...
NorthWet Posted November 14, 2008 Author Share Posted November 14, 2008 Have you tried posting this over on the SVX forum? http://www.subaru-svx.net I have had no previous luck with getting any technical question addressed, let alone answered, in the SVX forum. I have my thoughts about the reason(s), but this is not the forum for such thoughts. TC stall seems to be just fine. I would tend to agree that it is the loss of line pressure, but not sure why. It is sharp, and at a specific and consistent RPM. I was going down my favorite hill today in selected-2nd, and allowing the tranny to bump up against this RPM limit on overrun. Engine would speed up in response to engine braking down hill, hit 3100 rpm, tranny would "release", RPM would drop just a little, tranny would catch again, and cycle would repeat. Link to comment Share on other sites More sharing options...
bheinen74 Posted November 14, 2008 Share Posted November 14, 2008 the tranny in the SVX is identical to the legacy turbo's of era 92-94.My 94, cruising at the 3100rpm range on the interstate at 70mph, that is the rpm that is drops down into overdrive when fully warmed up to drop the rpm to 2850. or when you go to pass someone accelerate a tad, it comes out of overdrive up to the 3100, then drops backinto overdrive. Link to comment Share on other sites More sharing options...
NorthWet Posted November 15, 2008 Author Share Posted November 15, 2008 Technically, it is not identical. It shares the R4AX-EL core, but certain details are different. I do not think that it is trying to shift into fourth gear, if that is what you are implying. A very unlikely scenario for the example of engine braking in selected-and-locked second gear. Link to comment Share on other sites More sharing options...
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