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A/T no D-light (and no delight)


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In what way won't it shift?

 

Two possibilities come to mind:  One is that your shift linkage is misadjusted or jammed.  The other is that your Tranny's governor valve/driven gear has problems.

 

The "D" light may be not coming on because of the linkage, but more likely just burned out.

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It will not shift up from 2nd to 3rd, though it did shift up from 1st to second ok. The D light was working 2 days ago when I took it for a test drive and it shifted through all the gears OK. Does the tranny have a Vehicle Speed Sensor to sense a shift, or is it just a pressure thing? It will manually shift from second to first and back.

 

I'll try adding fluid and see if that helps. The only fluid loss was the transmission cooler in the radiator and the torque converter when I pulled the engine.

Edited by Luvn737s
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The torque converter typically holds half of the ATF volume, so its "loss" could be significant.  Speed sensing in the 3AT (really an JATCO M41A) is hydromechanical via a rotating governor valve run off of the front differential..   The valve gums up, develops tight spots, both of which need to be dealt with by (easy) removal and rework.  The driven gear on the valve tends to wear abnormally ("Apple core", due to the wear pattern) requiring replacement of the gear.

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Valve cleaned and replaced (gear looks very good) and no luck. Actually trans will not shift out of 1st automatically. 2nd can be manually selected. When moving if Drive selected ( manually out of 1st or 2nd) very little engagement occurs acts like it is slipping. No slipping at all in 1st or 2nd. Is there a chance there is a vacuum line that is incorrectly connected? What does the vacuum line do for the trans? Could a blocked filter cause this? How about a torque converter that is improperly seated?

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How did you clean the valve?  Complete disassembly, deburring all edges and polishing all sliding surfaces, so that EVERYTHING slides "as smooth as butter"?

 

Could still possibly be ATF level, but proper shifting manually but improper shifting in "D" usually points back to the governor valve.  There is no filter (just a debris screen), and the vacuum hose goes to a vacuum modulator (auto parts computers use a different name) that provides "kick down" downshifts under heavy throttle; it should not have any effect on normal upshifting, but they do sometimes rupture their diaphragm and suck ATF into the intake manifold (producing white smoke out the tailpipe).  If the TC was not properly seated, there would be either mechanical noise from parts grinding themselves to destruction, or a broken input or oil-pump drive shaft (resulting in the tranny not functioning at all).

 

If the car manually shifts, the basic functioning of the tranny is good.  To me, the problems point to governor valve, or perhaps the AT's valve body valves that are controlled by the governor valve.

Edited by NorthWet
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I cleaned it with carb cleaner thinking I might find some goo in there, but it was clean and everything moved very easily. The cover for the governor only had a very small amount of fluid in it. I was expecting it to be full for some reason. 

 

What about band adjustment? I see very little about how or why it is done. 

Edited by Luvn737s
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I would double check the governor as I have had clean and seemingly free ones the would not shift. As far as adjusting the band it is fairly simple and the procedure can be found in Haynes or Chiltons ( at least it is in mine ) or it can be found here http://jdmfsm.info/Auto/Japan/Subaru/--Old%20Models--/1983%20Subaru%20EA81.pdf in section 7 page 34 item 10.

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She shifts! Now we're down to one shiftless thing around the house!

 

I fully disassembled the governor and polished the bores with XXX steel wool and cleaned it again and reassembled. Thanks to whomever posted the disassembled governor, that was really helpful. 

 

Happy Thanksgiving everyone. 

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Did you follow the directions on deburring during the cleaning?  That procedure works pretty well.

 

The last couple that I have done, I did do a light "hone" on the bore.  I wrapped some crocus cloth around a drill bit in a cordless drill, lubed the bit with a bit of ATF, and used that to hone the bore.  

 

Regardless, if done well, you probably won't have to clean and debur it again for many years.

Edited by NorthWet
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I've had it apart and together a few times and each time it gets worse. I'm headed to the junkyards today. What year Subarus had the 3AT from which to try and get a replacement governor? Any other makes use this tranny (it is FWD only, not 4WD)?

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Welll, I rebuilt the governor for the fourth time and it could not possibly move any smoother, yet it won't auto upshift from 1st to 2nd or 2nd to 3rd, unless you tromp it and then at about 4500 RPM it will upshift for a moment and then back into 2nd. You can manually shift it from 1st to 2nd and it downshifts automatically from 2nd to 1st.

 

So, I am taking  a much needed break from this project to regroup and reassess. I found a 5 speed locally, but I would need a step-by-step guide to tackle something like that, AND it would have to make sure there was no need to eliminate the emissions controls since they have that money maker down here in Phoenix.

 

Orignally the problem was a broken timing belt, but I went the full monty on gaskets and oil/waterpump, etc in order to build my daughter her first car that could be as reliable as my previous Subarus have been.

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