Gear problem

toyota
transmissions
fluids

#1

Dear Cartalk,

I have a 89 toyota all-trac wagon and bought it second hand but it only still has 79.500 miles on it. No problems whatsoever… UNTIL! yesterday when it started very reluctantly hop-skipping into gear as I revved up to a 50 mile/hr speed. My mechanic just says it was low on transmission fluid and he filled it this morning and it seems okay. But he already did a 75,000 mile inspection on it two months ago and claims he had double checked the fluid level then and found no leaks this morning so where did the transmission fluid go? Weather here has been normal in the 70s and low 80s and I don’t think there was any evaporation. I drive 50 miles each way to work at a 65/70 mile/hr speed, which this thing works hard at. Does driving at high speeds affect the sinking of transmission fluid? I don’t see any puddles below the car after parking it all day… so… please help me solve the mystery…


#2

Many leaks are slow enouigh and only occur when the transmissionis hot and operatoing. So will lose it in dropsover a long distance, but almost nothing on you driveway. On some cars, like older GMs, the fluid can get sucked into the engine through a faulty modulator valve. It shows up as white smoke from the exhaust. Your car likely has an elctronically controlled transmission, and no modulator valve. The other areas of escape is the transmission oil cooler, where your fluid goes into the bottom of the radiator to be cooled.

I would check all external connections, as well as the coolant to see if there is any fluid in it.

Transmisison fluid does NOT EVAPORATE unless you heat it to the boiling point, at which your transmission would be toast.

Your driving speed should not affect the fluid level. Transmissions can go for years without the level going down. Make sure you and your mechanic check the level the same way; on most cars that is with the engine HOT and IDLING in Park or neutral. Set the parking brake!


#3

he never filled it properly 4kmiles ago


#4

Hi Docnick,
Thanks for this. It’s really helpful to know. I am disappointed in my mechanic as he was the one who said, “well it might have evaporated.” One thing I noticed after the 75000 mile check up was how tight the steering wheel seemed - that is, at the 65 mile speed that would have felt smooth on the wheel prior to my check up now seemed to bounce all over the place. I wondered if that meant my transmission was also working extra hard to get up to speed and whether the mechanic hadn’t over adjusted or over tightened the steering axle (is there such a thing?)l to the transmission during his last checkup. When the mechanic tells me he “checked for leaks,” would it be basic to check these external connections you speak of or should I mention it to him and ask him to take another look? As of now, it seems to be driving smoothly and I’ve taken to more moderate speeds of 55-60 an hour. Everyone on the California highway hates me. Sigh.


#5

Interesting! But it seems like a no brainer to check for fluid levels during a check up… Could my mechanic be so incompetent? Thanks!


#6

yes been doing this 20plus years and we have our bad days also.does not make him incompetant,JUST HUMAN!!!