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Transmission troubles

JML

New Member
Joined
Aug 13, 2021
Messages
14
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australia
Hey guys so I’ve had some issues with my transmission in my 3rz 90 series. I’ll try and sum it up:
Did a drain and refill, way more came out than my manual said to put in just figured it had been overfilled prior. A week in started slipping when upshifting and giving off a strong burning smell and slightly visible exhaust, checked the level which was real low. Over a few days added about .75 L, still low so did a drain and refill again. The atf was a thick mud brown colour now (bad sign I know).
Poured the remainder 3.25l and figured I’d just let a bit out at a time until level was right, only issue is my drain plug is now threaded and just spins, the dipstick reads about 1.5 Cm over the full cold mark so figured I shouldn’t drive it until I drain?
Should mention my dipstick takes some fiddling to get it in, and there’s about a half Cm difference on each side so is this normal?
I’m fairly sure the 2 L wasn’t enough because of slippage and burning smell, so wondering why the standard amount didn’t work.
Lastly wondering how seriously I might have damaged the trans in the process and how likely it could have contaminated the coolant and engine (due to a bit of smoke).
Should add I booked in a mechanic last week but have to wait until the 31st so stuck worrying until then.
 
I'm probably going to tell you things you may already know but here goes.

The consensus on here is that around 5 litres comes out on draining rather than the 2 litres the manual says. Brown and muddy isn't great and suggests it hasn't been changed in a long time, not necessarily a disaster.

Getting the fluid level right is a bit of a faff. The level needs to be checked when the atf is warm and with the engine running in park (or neutral for a manual). Obviously on level ground and using the "hot" marks on the dipstick. I usually put back in what I took out but that's no good if the level was wrong before or there is a leak.

If there has been cross contamination of coolant and transmission fluid there is usually a pink, milk-shake look to what comes out and possibly evidence of oil in the coolant (less so than the other way round as the coolant is under higher pressure) or obvious coolant loss.
 
cross contamination of coolant and transmission fluid there is usually a pink, milk-shake look
That’s a relief as it’s neither milky white nor pink milkshake (was aware but still figured safest to assume the worst). Definitely makes me a bit less worried, as I dreaded contaminating the coolant and blowing a head.
I will drive it til it’s hot and do a test once I’ve got the drain plug secure, just figured it was safest to not drive it at all if it was high.
 
Just spotted my comical error "put in neutral if it's a manual" - you wouldn't be checking your auto trans fluid in a manual, doh! It's early in the morning here!

Hope it works OK when you get the level spot on.

There is a school of thought that putting fresh fluid in an old box can stir up all sorts of crud and cause problems but you're already beyond that stage and I personally would always want clean fluid.
 
Thanks mate, I'll probably see if I can do a few fills and refills and maybe fit an external cooler for now.
 
Just spotted my comical error "put in neutral if it's a manual" - you wouldn't be checking your auto trans fluid in a manual, doh! It's early in the morning here!

Ha! Ha! --I missed that one.

I did wonder about the "The level needs to be checked when the atf is warm and with the engine running in park..." bit though. I thought that it wasn't possible to start the engine or have it running while in Park, coz that locks up the transmission & driveshafts? Bear in mind though, what I know about automatic transmissions could be written on the back of a postage stamp.

@JML --For what it's worth, my transmission fluid was brown too before I drained and refilled it. Mine got a really good draining because of...


...and I must have put about 6 1/2 litres back in afterwards to bring it up to the proper level and now my ATF is...

[drumroll]

...er... still pretty brown!

I'm planning to give it another drain and refill as soon as I sort out a proper sump plug. But my transmission ran perfectly fine before I did the drain and refill and runs just as good now --in spite of the fluid not being the cherry red colour we all crave. So, I guess brown ATF isn't the end of the world. Mind you, mine was [and is] quite transparent, in spite of being brown. I'd be more worried if it was brown and also full of crud.

[Why are the words "tempting" and "fate" rattling round my skull, after writing the above?]
 
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Hi Stuzbot - the engine will only start with the transmission in Park or Neutral. There is an interlock that prevents it starting in any other position.

JML - For the transmission fluid level, I found it tricky to get a reading on the dipstick but it is possible with a bit of perseverance, and important to get correct. As MODVRS said, engine and transmission needs to be running and at normal operating temperature and on level ground. Use the hot marks on the dipstick. You need to cycle through the gears a couple of times too, pausing for a few seconds in each position before you take the reading. This allows fluid to fill all the clutches, solenoids, valves, passageways etc.
 
Hi Stuzbot - the engine will only start with the transmission in Park or Neutral. There is an interlock that prevents it starting in any other position...

Ah. Got it. I've only ever tried to start the engine in Neutral

For the transmission fluid level, I found it tricky to get a reading on the dipstick but it is possible with a bit of perseverance...

Same here. Every time I looked at the dipstick, it just looked like someone had randomly splashed ATF across it. There was no visible demarcation line across, like you get with the oil dipstick. I think in the end I managed it by the technique of squinting edgewise along the back of the dipstick where it didn't look like there was any ATF at all and noting where it was wetter than the rest.

There's definitely a knack to it and, when I finally did manage to get a reading [and with the transmission hot too] I found that I was about 1 1/2 litres short of the MAX HOT level and, since I'd just replaced whatever amount I'd drained out, it had presumably been running with low fluid for years before I bought it. Seemingly [fingers crossed!] with no ill effects.
 
Stu, Park locks the driveline side of the transmission, but you can still spin the engine side shaft just fine. It's the same as neutral just with an extra locking pawl to prevent the output shaft from turning.
 
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