Inconsistent Transmission Oil Level

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Yaut
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My tercel:: 1985 Toyota Tercel 4WD automatic, lifted 1.5", 15 inch wheels

Inconsistent Transmission Oil Level

Post by Yaut » Sat Feb 23, 2019 8:00 pm

Have any other owners of automatic T4's run into the same issue as me? After driving around for several miles until the car was nice and hot, I check the transmission oil level and it was reading extremely over full. So, following the owner's manual directions, I put the car through all the gear positions and check it again and all of a sudden, there is no oil at all reading on the dipstick. So I insert the dipstick over and over again and after each check, the oil level rises until finally, the dipstick is reading well overfull again. Then, after checking it over and over again for 2 or 3 minutes straight, no oil is showing on the dipstick again.

What the heck is going on. Either my transmission is super low or super overfilled, I have no idea.
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Sat Feb 23, 2019 8:12 pm

According to the manual, the drain and refill quantity is 4.4 quarts so maybe I can just drain it and add exactly 4.4 quarts. Still, I don't trust that that will be an accurate way of filling it.
'85 Toyota Tercel DLX 4WD (tan)
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Petros
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Re: Inconsistent Transmission Oil Level

Post by Petros » Sat Feb 23, 2019 10:42 pm

make sure you follow the instructions for checking ATF level. the oil expands when it gets hot, and it will change the level shown on the dip stick. also, if you are in parked, or in gear, it will show different levels, as well if it is idling, or engine off.

I do not know about the Tercel4wd auto trans, but some cars require you to check the ATF level when in "drive" with engine idling, some with engine off and in park. some with engine idling, but auto trans in neutral. All of these will give different levels, make sure you do as the owner's manual instructs.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Sat Feb 23, 2019 11:03 pm

Yes indeed. Followed the manual's direction precisely. It has very replicable behavior. The manual's procedures are typical for most auto trans. Get it hot, park it level, run it through the gears, check it in park. Very strange.
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Re: Inconsistent Transmission Oil Level

Post by xirdneh » Sun Feb 24, 2019 1:27 am

I would look into how much fluid stays in the torque coverter . Or find out how to empty it. Otherwise you may put too much in.
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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Petros
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Re: Inconsistent Transmission Oil Level

Post by Petros » Mon Feb 25, 2019 1:15 pm

if you run it hard the ATF can foam up, giving you a false high level indication. Not sure what causes it, but I have seen it. might be best to check level after a warm up from cold without driving it much. it typically happens when hot after a long up hill run at hwy speeds.

Additives are supposed to prevent foaming, but who knows what restrictions the federal government have forced AFT formulation changes.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
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TracDoc
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Re: Inconsistent Transmission Oil Level

Post by TracDoc » Mon Feb 25, 2019 8:32 pm

Yaut,
I have an auto and I have never had the problem you describe. A few things I can think of are:
1. The transmission filter is plug and when enough oil accumulates in the pan, the pressure in the pan becomes high enough to push the oil thru the filter into the pump or when the oil viscosity becomes low enough, as the oil gets hot, the oil passes thru the filter to the pump.
2. The rubber hoses going to the radiator are swelling up and restricting oil flow and a surge oil of flows thru the hose when the pressure gets high enough (I think this one is a long shot, but, I have heard this can happen to brake hoses).

I would remove the oil pan, look to see if the filter is clean, look for any debris in the pan, and either clean or replace the filter if there is nothing in the pan. If there is something in the pan, you have to figure out where it came from to fix your problem.

Also, on the 85s and maybe other years, there is a transmission oil temperature sensor that also activates a dash light when the fluid is low. I have tested this on my car and the light comes on when the oil is at the lowest cold mark on the dipstick. If your light is not coming on when the oil is low, you might want to make sure the sensor and the dash light are working.

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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Mon Feb 25, 2019 9:46 pm

Thank you all. I will take these suggestions into consideration and check it out here in a few days. Good information. Oddly enough, I have read about a temperature light for transmission oil but my car doesn't seem to have it. Where on the dash is your low level light? Otherwise, the transmission seems to work well. Also does your auto have a slight whine? Similar to the whine some manual transmissions make?
'85 Toyota Tercel DLX 4WD (tan)
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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Mon Feb 25, 2019 10:02 pm

After reading the manual, it seems the transmission temperature light is combined with the engine temperature light. I know the temp light itself works (still need to flush the radiator) but it I will definitely test that the sensor in the tranny also turns the light on.
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Petros
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Re: Inconsistent Transmission Oil Level

Post by Petros » Tue Feb 26, 2019 12:25 am

I was once driving an AT T4wd on a road trip on a hot summer day, up a long mountain pass, the coolant temp was high and than a "A/T temp" light came on the dash. it was red, I have never seen that before, as I recall it was along side the speedo where there are a vertical column of idiot lights. the location of it should be shown in the owner's manual.

I pulled over, let it cool and topped up the coolant in the radiator. The tercel used a compartment in bottom of the radiator to cool the trans fluid. that is a good reason to add an auxiliary transmission oil cooler in front the of the radiator.

you should see it when you turn the key to "on" or run, without the engine running. all of the idiots lights are supposed to light up as a check. They should all go off after you start the engine.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Tue Feb 26, 2019 11:39 am

Thanks Petros,

After studying the wiring diagram, it appears the transmission temperature light is shared with the engine temp light on the 85' model where the light will come on if either the transmission or engine is hot. I believe it is in the same position where the "EL" light would be on a manual transmission car. I know the temp light itself works because my engine sometimes gets hot at highway speeds and will light up when the engine temp gauge is also reading high. I will crawl under and test that the transmission temperature circuit is also good and may remove the sensor and test it in hot water.
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

TracDoc
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Re: Inconsistent Transmission Oil Level

Post by TracDoc » Tue Feb 26, 2019 10:13 pm

I do not recall any whine coming from the trany of my car. Can you give me an idea when you hear the whine like in first gear when the car is starting to move?

You can get an idea if the temp light circuit is working by disconnecting the transmission sensor wiring from the sensor. Doing that should make the light come on. If everything related to the temp light is working correctly and the trany is actually low on fluid, there must be another way the sensor is making a connection to ground. Maybe the insulation on the sensor is cracked and oil has entered making a grounding path.

You are correct about the EL light and the temp light location.

I never knew that the temp light is for both engine temp and trany oil temp. The only time I have had the light come on is when I was testing it. I have never had a cooling problem with my car. Even on 110 deg. F days with the A/C running, it always stays well below the middle of the coolant temperature gauge.

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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Tue Feb 26, 2019 11:32 pm

Yes. The previous owner ran straight water in it and the radiator has a fair amount of blockage. Haven't gotten around to cleaning it yet.

The whine I hear sounds like the whine older transmissions make with straight cut gears. I only really hear it at low speeds and it sounds like it is from either the tranny or differential. It does not sound alarming however. It's probably not normal but it is a 35 year old car.

I bought a new filter kit for the transmission and will likely be dropping the pan and replacing it this week. The oil looks very good so I'm not too worried about the shape of the transmission in general.
'85 Toyota Tercel DLX 4WD (tan)
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Re: Inconsistent Transmission Oil Level

Post by Petros » Wed Feb 27, 2019 1:51 am

often the filter is just a screen (not much of a filter). those are not really necessary to change, anything big enough to get caught in that screen means the transmission is doomed anyway. some use fabric filter cloth, those are worth changing as the collect the fine dust worn off the friction bands and clutches. it is a messy job, but necessary to keep it in good repair.

a gear whine can be normal for a trans or diff. if it does not change over time likely will never be a problem. changing old ATF might help that, or replacing the rear diff gear oil. I have had good luck by adding a valve body cleaner to to old auto trans, it cleans out sluge and usual improves shifting on older trans. a trans shop will tell you it needs a rebuild, but so far, no matter the shifting problems with perhaps 5 older cars with autotrans, I have never had to have them rebuilt, the shift problem went away after fresh ATF with valve body cleaner added to it. Ha! so much for "experts", who of course have something to gain by telling you to have it rebuilt.

When I was little, my parents had a fairly loud whine from our family Oldsmobile differential since we bought it used (a 1968 as I recall) We had it since I was in 5th grade up through my collage. We drove it over 100,000 miles and it never changed. It was given to my younger brother to take to collage, he eventually sold it with the gear whine still in the rear diff (about 1982?), despite a lot of abuse and a least one wreck (rear ended). that car was indestructible.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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Yaut
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Re: Inconsistent Transmission Oil Level

Post by Yaut » Wed Feb 27, 2019 8:15 am

Petros

Great information! I will try it out. I'll report back with the results. Fortunately it shifts good at the moment but it does shift a little hard when cold. Will be nice to see if this improves it any but hard cold shifts is a common occurrence for older autos anyway. At least the old worn out ones I'm used to haha.
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

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