4ATE transmission trouble

[briankk]

MY '94 SVX transmission works fine, but for one little thing...  I'll be driving along and lift my throttle foot, a gentle clunk from underneath, and the trans seems to uncouple from the engine.  Engine works fine, car coasts to a stop.  Trans shifter no longer has any effect on the trans, row it around as you please, there are no gears there at all.

 

THEN, turn off the engine, wait a moment, restart, gears all present and accounted for, drive away..  Near as I can tell, only happens on throttle lift or overrun, repeats every 2 miles or so..

 

Nearest Soob specialist declairs problem impossible.  Nearest dealer is baffeled.  No joy anywhere.  All ideas entertained.

 

FYI, recent fluid & filter change, new fluid looks as good as old, fluid level OK.  Car went about 150 miles on new Dexron 3 before problem cropped up.

 

No warning lights, sounds or codes thrown.  Is puzzelment.

 

BTW, I reckon it's standard 4ATE but for 3.54 ratio, no chips or other fiddles involved

[mikaleda]

Definitely sounds like an electrical problem of some sort. I think I'd start by verifying power is getting to the tcu when this happens.

[john in KY]

Electrical a good guess what  is causing that clunk? Anyway you can check for line pressure when the problem occurs? Thinking maybe a TC or pump problem. Not a transmission guy but thinking there is a port somewhere where a pressure gauge can be attached. 

[briankk]

Called Aamco. They speculate weirdness in the range sensor/neutral safety switch.  Have appointment with local shop to replace that sucker, tomorrow PM.  BTW, local is not aamco, their neaest is abt 70 miles from here, which would take a long time, 2 miles at a time...

[impostor]

Former transmission guy here. If you speculate that it is an electrical problem just unplug the connector that goes to the trans. Almost every transmission has a mechanical fail safe if power is lost. The only oddball I've ever run in to is the Allison LCT 1000 used by Chevy in the duramax and 8.1 liter. Your problem sounds like something with the pump or filter. Is it an oem filter, and installed correctly? The clunk part is odd and it may be unrelated.

[impostor]

On an svx, if it were me, I'd unplug the tcm instead. Removing the intake duct to access the connector is risky. The PCV nipples like to crack and the hoses might be brittle. I never saw that many Subarus in my days at the trans shop so I'm not sure if they default to second or third when there is no power to the solenoids, but at least this will help you isolate your problem to mechanical or electrical.

[briankk]

Former transmission guy here. If you speculate that it is an electrical problem just unplug the connector that goes to the trans. Almost every transmission has a mechanical fail safe if power is lost. The only oddball I've ever run in to is the Allison LCT 1000 used by Chevy in the duramax and 8.1 liter. Your problem sounds like something with the pump or filter. Is it an oem filter, and installed correctly? The clunk part is odd and it may be unrelated.

I did as you reccomended, trans failed disconnected, but slightly different.  With the TCU hooked up, is goes clunk and quits, w/o the TCU, it drives along gradually slipping 'till thewre's no more drive, and coasts to a stop.  Damn...

Edited May 27, 2016 by briankk

[1 Lucky Texan]

isn't the SVX known for trans issues? seems like I recall that.

 

maybe check at NASIOC too.

Edited May 29, 2016 by 1 Lucky Texan

[briankk]

Well, I guess this trans is done.  I'm not going to pay $3500 for an overhaul of the dodgy auto box, but might spend a few thou on a 5-speed replacement.

 

Is there anywhere a comprehensive list of what needs to be done for this?  I can get a 4.44 5 speed and rear end reasonably enough hereabouts, having something  to use as a chekoff list would be helpful..

 

Were there every any mount points for the hard parts on the SVX?  Master cyl, pedal shaft and whatnot?  Will a '99 trans bolt to a '94 SVX, given installation of flywheel, clutch and what not?

 

The '94 is OBD 1, the '99 is OBDD 2, will these reject each other? 

 

etc,ect, any help welcome...

[idosubaru]

I'd get a cheap 4EAT and add a transmission cooler and be done with it.

 

5 speed: Huck is s member here who did the first known swap a long time ago. In general for subarus need driveshaft, clutch pedal assembly, rear diff, center console and shifter, clutch cable bits, cruise control computer, flywheel, clutch, pressure plate,

 

I'm uncertain of svx specific needs but I recall something needing cut and welded - on the pedal assembly I believe.

[1 Lucky Texan]

check here; http://www.svxworldforums.com/

 

http://www.andysautosport.com/auto_parts/subaru_svx.html

 

http://www.subaru-svx.net/forum/

 

here's one interesting thread at NASIOC; http://forums.nasioc.com/forums/showthread.php?t=2305389&highlight=svx+transmission

 

others; http://forums.nasioc.com/forums/showthread.php?t=2299534&highlight=svx+transmission

 

http://forums.nasioc.com/forums/showthread.php?t=2331112&highlight=svx+transmission

 

http://forums.nasioc.com/forums/showthread.php?t=1579052&highlight=svx+transmission

 

you can find more threads there on the SVX.

 

seems like you need a lot of money to keep these on the road and there's almost no aftermarket parts available.

[briankk]

Thanks Tex, that's about as much useful SVX info as I've ever seen in one post.

 

I do wonder about the SVX weight.  The car I m' fooling with now, I bought in 4 pieces, the rolling chassis, the engine, and 2 trans, one allegedly good, actually not.  When the PO had removed the front axles, he'd broken the anti-lock tone ring on the RF corner, had to replace the entire front upright, have the old one in a box on the porch.  It continues to amaze me every time I walk by, the thing is just the perfect size for duty in the front end of a 3/4 ton Chevy pick-up...  Why, I wonder...