Automatic transmission fluid level

[jreask]

I drained three quarts out of my automatic transmission and replaced it with three fresh quarts of new fluid. My question is about the fill level. When I check it with the truck warmed up in Park after shifting through all of the gears, the level is at the middle of the hot lines on the dipstick. Good, right ?
When I check the fluid level with the truck cold in the morning, the fluid is above the hot area of the dipstick. I can only assume that some fluid must drain out of the torque converter or transmission overnight and that's why it reads above the hot lines? Anybody know for sure about this ? Thanks for your help.

JR

 

[pauldub]

Sounds like when you checked it cold, the engine wasn't running. There's drain back when you shut off the engine.

 

[psraff]

I believe that sounds right. I've always been taught to check tranny fluid while idling and warm for correct readings. Also, it looks like your driveway is slanted pretty good. Check fluid with the truck in the same place both times?

 

[WallyWest]

Cold readings, even with the engine running, are notoriously unreliable. And if you check it with the engine off it will read way high.

 

[mtbtim]

If the engine is running and you're on level ground, there's no way the level on your dipstick when cold should be over the hot level. What's interesting is you're only draining out 3 quarts with a drain and refill. I'm averaging closer to 5 quarts when I do a drain and refill.

 

[jreask]

Sounds like when you checked it cold, the engine wasn't running. There's drain back when you shut off the engine.

That is correct. And that was the answer I was looking for. So there is a drain back when it's shut off.

 

[kolelt]

The auto tranny dip stick has hot and cold on it though

 

[mtbtim]

That is correct. And that was the answer I was looking for. So there is a drain back when it's shut off.

You always have to have the engine running to check an automatic transmission fluid level. This is one of those things every vehicle owner with an automatic transmission should know but I'm learning many don't know this. At my fire department, I always try to impart some of my knowledge to the new guys and I find many of these youngsters have very limited experience when it comes to general automotive mechanics.

 

[gamefreakgc]

If the engine is running and you're on level ground, there's no way the level on your dipstick when cold should be over the hot level. What's interesting is you're only draining out 3 quarts with a drain and refill. I'm averaging closer to 5 quarts when I do a drain and refill.

Unless you do a drain and fill with cold fluid! Same goes with engine oil, you have to wait a loooong time for cold fluid to make its way out of all those little passages.

 

[WallyWest]

Incidentally, my 2008 Jeep GC doesn't even have a dipstick, because Chrysler thinks owners are too stupid to check it. The tube has a cap on it with "dealer only" printed on it.

Anyway, the "tool" to check it can be purchased and it doesn't have hot and cold marks. It has a range with temps on it, and a chart that you look at to decide where the fluid should be based on fluid temp. You need to use a scan tool to determine fluid temp.

I've found that level ground makes a HUGE difference too. The street in front of my house is level at one point, but slopes up from there. Not much, most people would consider the whole thing level. But my trans reading is quite a bit different depending on where I park.

Point is, if it's in the general vicinity of right then you're ok. If it's a little bit high that's ok too, just make sure it's not low. And get a Scangauge, or something like that, to keep an eye on your fluid temp. Especially when you're towing, off-roading, anything that puts added stress on the trans.

 

[lilsid112]

Lately I've been measuring how many quarts I've drained when it comes to ATF changes. Much easier this way so I'm playing the guessing game later on. The most important reading is when the fluids warm with engine idling. Sounds like you're spot on sir!

 

[Lamer]

reviving an old thread here. but I have some wildly varying trans fluid level readings on the stick.

I had just completed the Transgo shift kit install and put some new fluid in to replace all that had drained. I hadnt measured the exact amount but it was about a gallon. so that's what I added: Valvoline Max Life Full Synthetic.

after the install and adding new fluid I took it for a test drive. the shifts are noticibly sharper. especially 1 to 2. but anyways, once I was at speed and had to stop at a stop sign, then go again, it would rev up to 2k and not move at all, and then down shift to 1st maybe 3 seconds later. thought this was a sign of low fluid level.

I added another quart of fluid last night and checked the cold level this morning. it was half way through the cold and hot marks. and upon driving, the issue seemed to be fixed. HOWEVER...

when I check the level after driving for 20 mins its half way to the cold mark, which seems odd. see below:

Anyone have some guidance on this? [MENTION=120071]mtbtim[/MENTION] any advice?

 

[mtbtim]

reviving an old thread here. but I have some wildly varying trans fluid level readings on the stick.

I had just completed the Transgo shift kit install and put some new fluid in to replace all that had drained. I hadnt measured the exact amount but it was about a gallon. so that's what I added: Valvoline Max Life Full Synthetic.

after the install and adding new fluid I took it for a test drive. the shifts are noticibly sharper. especially 1 to 2. but anyways, once I was at speed and had to stop at a stop sign, then go again, it would rev up to 2k and not move at all, and then down shift to 1st maybe 3 seconds later. thought this was a sign of low fluid level.

I added another quart of fluid last night and checked the cold level this morning. it was half way through the cold and hot marks. and upon driving, the issue seemed to be fixed. HOWEVER...

when I check the level after driving for 20 mins its half way to the cold mark, which seems odd. see below:

Anyone have some guidance on this? [MENTION=120071]mtbtim[/MENTION] any advice?

Are you checking the fluid while on level ground and with the engine running? When cold (vehicle hasn't been driven anywhere) you would want to see the fluid level on the dipstick in cold range, preferably at the top cold mark. After you've driven it for a while, say at least 10 miles, you should expect to see the fluid level in the hot range. Ideally, you have a way to monitor your trans temp either with an OBD II reader sending info to a phone app or you have a scan gauge or ultra gauge for your 1999 - 2002 model, or you use an aftermarket trans temp gauge for your 1996 - 1998 model.

I like to have my fluid level to the top hot mark on the dipstick when I've reached an optimum operating temperature which is around 170 degrees. One way to raise your trans temp without moving anywhere is you set your parking brake, transmission in drive, have your left foot on the service brake, your right foot on the accelerator pedal and you raise the engine rpms to around 1000. This puts a load on the trans and will raise the trans temp pretty quickly. You watch your gauge, phone app or scan gauge and you bring it up to around 175-180 degrees. The reason why you bring it up a little past 170 is your temp will start to drop pretty quickly. So, you get it up to the 175-180 degrees, get out of the rig with the engine running and check your dipstick level. If it's not up to the top hot mark on the dipstick, I add some fluid and then bring the trans back up to temp and check it again. I keep doing this until I get the level to the top hot mark on the dipstick.

What you also need to know is the hotter the trans fluid gets, the more it will expand. So, if you checked your fluid level and the trans temp was at 200 degrees, you would see that the fluid level was above the top hot mark.

As you can see, an automatic trans fluid level isn't really an exact science. The important thing is to get it pretty close, I'd say within a 1/2 quart of being perfectly dialed in. I don't think it's a big deal to be a little under filled or a little overfilled. You just don't want to be way under filled or way overfilled.

My two and a half cents on this subject.

 

[bootown]

Not sure if it's different for the 96-98 but for an 02 (99-02 I think) if you're checking when cold you need to be level, start the engine, run from P to L back to P, pull the dipstick, clean it, then check the level. Should be in the cool range. That gets you in the ballpark.

Then you want to get the transmission temperature between 158-176F and check the level using the same method mentioned at the beginning. The cool check is only helpful to get you started if you have no idea where your level is at and don't want to cause any damage by driving it around to warm up the fluid. If you're not slipping then you're probably good to go straight to the operating temp check. The cool check has never seemed close to accurate to me.

 

[Bad Luck]

Hot temp check should be done with trans fluid temp around the 160 or hot enough to make you say "f*ck" when you touch the dipstick metal because you couldn't bother to find a rag. I'm also a big fan of the 3 swipe method. Pull the dipstick out, clean it, put it back in, and repeat that again. Checking the fluid level on the 3rd or 4th pull. Helps make sure there's no fluid in the dipstick tube causing it to read wrong.

 

[phattyduck]

Not sure if it's different for the 96-98 but for an 02 (99-02 I think) if you're checking when cold you need to be level, start the engine, run from P to L back to P, pull the dipstick, clean it, then check the level. Should be in the cool range. That gets you in the ballpark.

To put a finer point on it, you should wait 1-2 seconds in each shift position all the way down and back up (P-R-N-D-2-1-2-D-N-R-P) before checking the level.

Luckily, the A340 is not very picky about fluid level. A number of other Toyota transmissions (FWD ones, in particular) are VERY picky about level - like, 0.25 quart high or low causes shifting issues.

-Charlie

 

[Lamer]

Are you checking the fluid while on level ground and with the engine running? When cold (vehicle hasn't been driven anywhere) you would want to see the fluid level on the dipstick in cold range, preferably at the top cold mark. After you've driven it for a while, say at least 10 miles, you should expect to see the fluid level in the hot range. Ideally, you have a way to monitor your trans temp either with an OBD II reader sending info to a phone app or you have a scan gauge or ultra gauge for your 1999 - 2002 model, or you use an aftermarket trans temp gauge for your 1996 - 1998 model.

I like to have my fluid level to the top hot mark on the dipstick when I've reached an optimum operating temperature which is around 170 degrees. One way to raise your trans temp without moving anywhere is you set your parking brake, transmission in drive, have your left foot on the service brake, your right foot on the accelerator pedal and you raise the engine rpms to around 1000. This puts a load on the trans and will raise the trans temp pretty quickly. You watch your gauge, phone app or scan gauge and you bring it up to around 175-180 degrees. The reason why you bring it up a little past 170 is your temp will start to drop pretty quickly. So, you get it up to the 175-180 degrees, get out of the rig with the engine running and check your dipstick level. If it's not up to the top hot mark on the dipstick, I add some fluid and then bring the trans back up to temp and check it again. I keep doing this until I get the level to the top hot mark on the dipstick.

What you also need to know is the hotter the trans fluid gets, the more it will expand. So, if you checked your fluid level and the trans temp was at 200 degrees, you would see that the fluid level was above the top hot mark.

As you can see, an automatic trans fluid level isn't really an exact science. The important thing is to get it pretty close, I'd say within a 1/2 quart of being perfectly dialed in. I don't think it's a big deal to be a little under filled or a little overfilled. You just don't want to be way under filled or way overfilled.

My two and a half cents on this subject.

Tim, I am doing everything you talk about, to a T, and I always check in my garage (very level ground) but I am mostly worried about putting too much fluid in, ill explain down below...

Not sure if it's different for the 96-98 but for an 02 (99-02 I think) if you're checking when cold you need to be level, start the engine, run from P to L back to P, pull the dipstick, clean it, then check the level. Should be in the cool range. That gets you in the ballpark.

Then you want to get the transmission temperature between 158-176F and check the level using the same method mentioned at the beginning. The cool check is only helpful to get you started if you have no idea where your level is at and don't want to cause any damage by driving it around to warm up the fluid. If you're not slipping then you're probably good to go straight to the operating temp check. The cool check has never seemed close to accurate to me.

Bootown, you and Tim both mention the coldmark as a ballpark level, but how ballpark are we talking?

after having driven around for a couple days, the trans seems to shift ok (If i floor it, I can get to red line in 1st gear, then it shifts to second and drops to 3k and the 4runner feels sluggish even though I'm still flooring it- is that large a drop an indicator of too little fluid???)

when stone cold: at the lower cold mark
when at 165deg and after driving 30mins: its halfway to up the cold mark. (worrying!!!)

So is it best to add more fluid and try to reach the mark ? that's a lot more fluid! I'll certainly be well over the COLD mark when the engine is cold.

Using Valvoline Full Synthtic Max Life if that adds anything...

 

[Bad Luck]

when stone cold: at the lower cold mark
when at 165deg and after driving 30mins: its halfway to up the cold mark. (worrying!!!)

Your trans fluid temp is 165? Where/how are you getting your reading? Do you have an external cooler?

 

[Lamer]

Your trans fluid temp is 165? Where/how are you getting your reading? Do you have an external cooler?

external cooler INLINE with my radiator, trans temp sensor installed in the OEM radiator feed line (just like Timmy the tool man!)

 

[Bad Luck]

external cooler INLINE with my radiator, trans temp sensor installed in the OEM radiator feed line (just like Timmy the tool man!)

Gotcha. I always set my trans fluid level hot. The cold level is to make sure you have enough fluid to operate the vehicle until the transmission is hot enough to adjust your fluid levels.