CHECKING Transmission Fluid Level

Hi,

Yes I know how to drain and fill and did a complete procedure a year ago but getting ready for some heavy use and just want to check levels.

I was considering adding about 1/3 quart fluid when cold. Drive up the temp, open fill and let drain to proper level.

BUT When cold isn't there an excess of fluid in the pan higher than the fill mark? So opening the the fill plug would drain perhaps more than the 1/3 quart? I'm not talking about draining at all! it's got a full compliment of Valvoline 30K miles ago.

I don't know so am asking for a quick simple way to check!

Alternatively I can drive up to temp and then overfill drain.... this approach is sloppier though.

Thanks,

 

There is a check screw specifically for this purpose. You have 3 screws, drain, fill and check. You check the level by bringing up to correct temp. remove the check screw and excess will come out. Plug it when there is a small trickle. There is a write up in the sticky, just for drain and refill of the pan.

 

Just had to do basically the same thing on my truck. When the truck is off and the transmission is cold, the trans fluid level, even properly filled is below the fill plug level. So you have no worries pulling this plug and adding fluid, then running the truck to correct trans temp.

 

Right!

But should I over fill a little so I'm just draining?

Since it's a small window of keeping between 115-130° and IF no fluid drains it's a delayed process.

I got confused with rear diff lube check that drains from the fill.

Is the fill plug sufficiently higher than the drain check so by opening to add a little fluid I don't dump any even when cold?

Will 1/3-1/2 quart excess cause issues if just for a few minutes?

Thanks and sorry for confusion. I did read the sticky and used that procedure last year but it doesn't cover check per se

A

 

You should overfill a little because the factory level check procedure says it's "right" when there is a small stream/dribble out of the overflow plug (whatever that term means to you).

But you should jump the OBD pins so you get into TEMP CHECK mode. Don't screw around with IR temp guns or whatever.. just use the factory mechanism so you know you have it right.

 

I added a full quart to the fill plug with the trans cold. Once the trans came up to temp, I drained almost a quart back out of the check plug. I wanted to ensure I had enough fluid in the transmission so I did not have to fill, heat it up, and then find out I did not have enough either.

 

You can add that quantity above and do the temp check. I did the same with 3/4. I would add it when it’s cold, jump the two pins and get it in check mode, when it gets to correct temp. pull the check screw and let excess flow out until it’s just a small trickle, then plug it.

 

It's the other way around. When COLD, the flow is lower than the overfill tube in the pan(assuming level is correct). After truck is started, fluid heats up and rises towards the top of the overfill tube inside the pan.

Fast Fwd. to about 12:00 in the following video - A750x Aisin transmission. Around 12:05 or so, you will see the overfill tube in the pan. Again, when fluid is cold, it's beneath the top of this tube. As it heats up, it rises. Man in the video explains the overfill from that point on.

https://www.youtube.com/watch?v=P1XdzmjdsPo

 

Thanks!

But isn't it a basically a sump though... So it would register as higher (drain excess) when stone cold AND engine off even if "lower"?

A