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1990 Legacy L, AWD, 4EAT, speedometer issues


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21 replies to this topic

#1 notnowles

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Posted 24 February 2010 - 10:06 PM

Hi, I'm new here, and a relatively new owner of a pretty old Legacy that I acquired from a friend/original owner.

I have posted my problem on another board, so if this is redundant for you, I apologize for that!

The "intermediate" speedometer drive unit that screws into the top of the transmission case seized and snapped.

I replaced it, pulled, lubed and reinstalled the cable, but have no speedometer function with everything reconnected.

I tried the cordless drill attached to the speedometer cable, and sure enough, the speedometer works fine.

Someone kindly suggested that I jack up front and rear on one side, run it, and see if the gear in the case turns, which I will do.

I rather suspect that there is a problem with the gear inside the trans, though, and I have not been able to pull the vertical gear up and out of the trans.

I see a small steel plug pressed into the side of the differential housing in line with the vertical gear, and I am wondering if there is a setscrew behind it which retains the vertical gear.

Maybe the trans has to be pulled and dismantled to remove the gear?

I realize it could be either the vertical gear, or the big one that is on the differential.

I am also getting 16 flashes of the "Power" light on start up, which is new. I read here that the speed sensor for the trans is in the speedo head, so perhaps that explains the 16 flashes.

What does the 16 flashes indicate? No AWD, or weird shifting pattern? It seems to drive okay from what I can tell, though I have not driven it a lot since the speedometer quit.

I know this is a long post. Thank you for reading so patiently!

Les

#2 eulogious

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Posted 25 February 2010 - 03:56 AM

Hello and welcome! Let's see if I can help here...

From the sound of it, the cable is fine, but it seems the gear isn't attached to the cable anymore, and that's why it's not working for you. I believe you will have to tear down the trans in order to get the gear to go back on, but I could be wrong since I have not done this myself.

As for the 16 flashes from the power light, that relates to the Duty C solenoid which controls the AWD, and the AWD needs to have both speed sensors (one in the front of the trans, one in the back) working in order to function, so it looks like one of you sensors is broke, which would tie into the speedo issue you are having. Here's a link to a post that has some good info at tearing down a 4EAT trans and a good look at the speedo gear in the trans:

http://www.ultimates...ht=Legacy trans

It's post #9 with the pics. Gloyale took some good photos, so they might help you out.

I would be careful driving around with the trans in that condition, mainly because when the duty C solenoid goes into "limp mode" it locks the MPT clutch effectively giving you 4WD all the time, and that is bad. It creates the torque bind issue that comes up with the 4EAT. So I would limit my driving until the trans is fixed. I think that is all the help that I can offer! Hopefully someone with more experience in taking these trans apart will chime in!

#3 2.5GL

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Posted 25 February 2010 - 04:22 AM

Clarification... 16 flashes indicates a problem with the transmission in general. Codes must be checked to verify the exact problem, usually electrical in nature. SINCE you have a known VSS failure, you can surmise that the codes are for the VSS problem. Yes the AWD will be forced into a greater bias for AWD, but I wouldn't park the car for this problem, just avoid full lock circles on dry pavement.... Since the speedo is not showing speed that is (one) of the codes you'll have. The sensor is in the speedo head itself, the other is the one on the back of the trans, and rarely goes bad.

And, if the gear you see in the trans does not move when the car is in gear, the gear in the trans is stripped and requires a tear down to replace.

Make sure the cable if firmly seated into the adapter thingy on the trans, I like to have the car in the air, trans engaged, and plug it in while the gear is turning, you can then immediately see the speedo work if it is all good.

#4 notnowles

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Posted 25 February 2010 - 06:32 AM

Thank you both for the helpful suggestions.

It's interesting that the bias is toward AWD now. Somewhere I read that the AWD would not be engaged if the speed sensor wasn't working. So, good to know about the danger of driving on dry pavement.

I will get a front and back wheel on one side off the ground and look at the gear inside with the trans engaged to see if the speedo driven gear is turning. Someone else suggested that I didn't need to have all 4 wheels off the ground, just 2, which I presume is because my car is too old to have limited slip.

It's an unusual set up with the speedo driven gear secured from the inside. I have replaced that gear on other cars from the outside, and have found that it is usually held in with a snap ring or set screw. And with both the driving and driven gears being nylon/plastic, I suppose either/both could be stripped.

I'm sure Subaru had their reasons for doing it the way they did.

The photos are cool. Now I know what the gears look like!

Thanks again!

#5 johnceggleston

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Posted 25 February 2010 - 07:05 AM

did you make sure the flat spade like cable end was aligned with the slot in the speedo gear end.? maybe try fitting a screwdriver in there and turn the wheel by hand.

#6 notnowles

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Posted 26 February 2010 - 06:38 PM

Just thought I would post a follow up to say that I have checked the speedometer gear in the trans on my 90 Legacy, and the gear is, indeed, stripped.

It had me fooled because it would turn a little bit when I moved the car back and forth, i.e., I would note the position of the gear, move the car, and look again, and invariably, the gear position had changed.

However, with wheels off the ground, the gear only turns a little bit, then stops, and when I do it with a screwdriver, and hold the handle, I can feel the stripped teeth trying to engage.

So, the moral to the story is, I think, if you have a car with a speedometer cable, you would do well to remove the intermediate drive unit and inspect it to be sure that it is not on the verge of seizing up and shearing off, because in my car's case, the intermediate drive not only broke, but the gear(s) stripped in the transmission, too.

The little unit is easy to dismantle, clean, and lubricate, as I did with the used one that I bought in a parts yard. I cleaned and lubed with moly grease and a drop of oil, and had it turning smoothly and sweetly, but to no avail, as the transmission now has an internal problem. I have no doubt that the seizure and breakage of the drive unit is what caused the gear teeth in the trans to strip.

I am uneasy about using the car very much, lest I totally ruin the trans,(so you're probably thinking: so what if you ruin it at this point?) given that the AWD bias is different w/o the speedometer cable information being available to the computer and transmission.

In my car's case, it will go to "winter standby status" for use when it snows and the AWD is useful, as the body on it is not good enough to warrant the time involved in fixing the trans problem.

And, I will keep my eyes open for a similar vintage example, in better shape, so that I can ultimately scrap my car and use it as a source of parts.

If I do get one of similar age, though, the first thing I am going to do is service that speedometer drive before it seizes!

Thanks to all for the help and advice.

You're a great group of people!

#7 johnceggleston

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Posted 26 February 2010 - 06:57 PM

the speedo gears are plastic and in no way will they effect the way the trans works or damage it. you just will not know how fast you are going. and with out the front speed sensor, there is a good chance you will not have AWD.

#8 notnowles

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Posted 26 February 2010 - 10:10 PM

Thanks for the info that I would not damage the car by driving it.

Someone said that the car might get into a torque bind situation (not sure what that is, actually) because the car would be in a 50/50 mode all the time w/o the speed sensor input.

To be sure, I had power to front and back wheels when I had it jacked up today and was checking the speedo gear for operation.

I have no idea, though, what the power distribution was.

So, you are saying I'm not going to hurt the car by driving it as is. That's good to know.

I'm not clear on what changes the bias from FWD to AWD and how much the trans computer has to do with it.

Thanks again for the helpful information.

#9 johnceggleston

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Posted 26 February 2010 - 11:18 PM

awd / tcu info.

http://www.ultimates...699&postcount=9

#10 eulogious

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Posted 27 February 2010 - 02:54 AM

If you just need to drive the car around on dry pavement, you can just throw a fuse in the FWD fuse holder and drive it around in FWD, and then if you need AWD, just pull over and remove the fuse and you will have AWD again. I know it's alittle bit of a pain, but you could still drive the car around. Just an idea. Good luck!

#11 notnowles

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Posted 27 February 2010 - 08:32 AM

Thank you both for the explanation, and the suggestion on the fuse installation!

Actually, the fuse installation might well be the ticket for the time being, until I figure out what I am going to do.

If the body were better on this car, I wouldn't hesitate to do the fix, but it's rough (the car was supposed to be my winter beater) but I have already spent a lot of time and a fair amount of $ fixing this, that, and the other thing, and at some point, you have to back off, and that trans tear down is big.

I don't know how difficult a job it is to R & R the trans on this car. I have done it on an AWD Audi, but not a Soobie.

Meanwhile, I will probably watch for a better example and plan to use my car for parts.

Any ideas as to what years most mechanical things on my car would fit, i.e., how new a model would my components fit?

Thanks again for the information already supplied!

#12 eulogious

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Posted 27 February 2010 - 08:42 AM

Something that I just thought of relating to the putting in the FWD fuse... You should make sure that the FWD fuse actual works the way it should, ie when you instert the FWD fuse, it's only turns the front wheels. The reason I bring this up is since you are already having problems it's possible that putting in the FWD fuse might not help you out at all. For instance, the physical wire that goes to the duty c solenoid is physically grounded out somewhere, so even if the FWD fuse is in, it will be locked in 4WD because the TCU doesn't actually control the solenoid at this point, since it's physically ground somewhere in the trans or on the car itself. So I would test it to make sure it functions the way it should before you go on a long drive. I just thought of that...

#13 notnowles

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Posted 27 February 2010 - 09:03 AM

Okay, thanks.

When I install the fuse, I'll jack it up and see if all wheels turn, or just the front ones.

What you say makes sense, though, because the TCU isn't really controlling things at this point.

I can't find anything in the owner's manual as to what fuse to install.

Any idea as to what amp fuse I should try?

Thanks again.

#14 eulogious

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Posted 27 February 2010 - 09:09 AM

I believe any fuse should work, it just needs to close the connection, so just use any size fuse.

#15 notnowles

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Posted 27 February 2010 - 09:10 AM

Okay, thanks!

#16 notnowles

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Posted 27 February 2010 - 10:13 AM

I did just confirm that FWD fuse installation does not eliminate power to the rear wheels, but it was a nice try, and thanks for the suggestion.

#17 eulogious

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Posted 27 February 2010 - 10:22 AM

That's sad :-\ Well at least you narrowed it down a little. Obviously something mechanical is going on with it, since software can't help. That really sucks. There are some super smart folks on here, so don't give up quite yet though! If I think of anything else I will chime in! Good luck!

#18 eulogious

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Posted 27 February 2010 - 10:23 AM

Did the FWD light come on on the dash with the fuse in? Just to verify that the actual fuse worked and was making the connection...

#19 Gloyale

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Posted 27 February 2010 - 11:55 AM

Ussually with VSS failure you LOSE the AWD.:confused:

If you still have rear drive after instalilng the FWD fuse, you may actually have another problem. (bad duty C)

#20 notnowles

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Posted 27 February 2010 - 04:09 PM

I definitely could feel the stripped speedo gears trying to connect when I had the screwdriver inserted into the key slot in the top of the gear in the trans.

My FWD light did come on when I put in the fuse.

I suppose I could have another problem, but I am skeptical, because the 16 flashes did not occur until the speedo quit. While I suppose a solenoid issue could have been cooincidental with the speedo gear's demise, it doesn't seem that even my luck could have been that bad!

Moreover, when I drove it today on errands, the speedo needle would occassionaly flicker to life momentarily, then drop to zero. (Those stripped gear teeth making contact occassionally, no doubt) On the runs when that happened, the next start up I would not get the 16 flashes.

Most of the runs, there was no speedo activity, and sure enough, the 16 flashes would return upon the next start up.

So, any signal from the VSS, even if it's momentary, seems to eliminate the 16 flashes on the next start up.

Probably put about 100 miles on it today, city and highway, and felt no ill effects from the AWD. Car shifted perfectly, ran smoothly, and with my GPS, I was able to gauge my speed.

I will think about doing the repair, but am still leaning toward looking for a better example of a similar vintage.

For those who have done it, is it a huge amount of work to get into the gears once the tranny is on the floor?

Like I said, I have done an AWD Audi A6, but not a Soobie.

Also, someone told me that I should buy a car no newer than 91 if I want my engine, etc. to be potential spares for the new car. Does this sound right?

Thanks again to all for your help, encouragement, and words of experience!

#21 Gloyale

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Posted 28 February 2010 - 12:32 PM

Enignes could be swapped from many newer models.

Trans for an excact bolt int you would need either a 90 or 91. Although there are a few other newer models with the same ratio and connectors.

#22 notnowles

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Posted 28 February 2010 - 06:42 PM

I am wondering about my car's engine in a younger car, i.e., at 114K miles, my car's engine seems strong.

I often see newer cars advertised with bad engines (mainly 2.5L models which often have blown head gaskets, or started with blown head gaskets and now have ruined engines.)

How far forward into a younger car's body could the engine in mine be transplanted?

Thanks again!




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