Sometimes it’s the easy stuff that gets me. I would appreciate an outside perspective so I can stop stressing and get this right.

1978 F250 RWD with 460, C6

Yesterday I replaced the transmission filter, which as you know requires removal of the transmission pan and loss of a lot of fluid. Much of it ended up on my driveway, so I don’t know much I “lost” during the process. :/

Even with the engine warmed up I’m having trouble getting a good or consistent read from the dipstick and am paranoid that I’ve under- or overfilled the transmission.

Here’s where I am:

After replacing filter and pan, I followed Haynes, adding about half a gallon (4 pints) of fluid. When I checked the level, fluid was smeared all over the dipstick. I checked a few times but couldn’t get a clear reading -- but there was always fluid present on one side of the stick or the other, sometimes low, sometimes high, sometimes smeared halfway up, etc. I turned on the engine to idle and shifted through the gears, confirmed no leaks. But I still couldn’t get a consistent clear read on the dipstick. I added a couple more pints a little bit at a time, with the engine idling. Every time I pulled out the dipstick, it looked different. I tried waiting a while after adding fluid to make sure it dripped all the way down, no impact.

I tried driving a couple feet, gears didn’t even engage. So I added another couple pints, a little at a time, with the engine idling. I still couldn’t get a reliable read on the dipstick, but I did drive the truck down my street and it worked much better. But after that if anything the fluid on the stick showed an overfill?

So where I am now is: in total I’ve put in a gallon of fluid since replacing the filter. The gears seem to engage smoothly when I drive the truck up and down my street except for a little hiccup when I go into reverse. So it’s not right yet. Then when I check the dipstick I can’t really tell what’s going on as there is fluid streaked all over it, including above the fill line.

I don’t want to drive a long distance to get the transmission fully hot given that I may be way underfilled and not realize it.

Questions:
• At this point I’ve added a total of 8 pints (one gallon), but the dipstick won’t give a clear reading and sometimes even looks like I’m overfull. Yes, I am checking it with the engine idling. I remove the stick, wipe it down, set it back in for a second or two, and pull straight out before doing my reading. What gives?
• Would you expect after losing fluid during a filter change to have to add way more than a gallon? I'm thinking I am underfilled perhaps.
• All this happened yesterday, so I can approach this later today with fresh eyes and a cold engine. Best approach?

Thanks so much all . . .

 

I often have the same issue.

I like to check it cold to get a general baseline.

I assume your dipstick has "cold" and "hot" marks on it?

 

What's happening is a typical problem on all kinds of dipsticks on equipment. what happens is when you pull the stick out to wipe it you draw a little fluid into the tube which gives you a variable reading when you reinsert it. an old trick is to wipe it off and slap it on your pant leg which puts a little dust on it ( for farmers and loggers anyway ) and this helps get a more accurate read.

You're probably obsessing on this a little. as long as it's in the general area of where it should be you're not going to hurt anything. if you're really concerned pull the dipstick out at night and warm it up the next day then stick it in and check it.

 

This works my grandpa showed me this trick when I was growing up on the farm, People look at you weird when you do it in a parking lot thought

 

Yes, that is more than possible. FTE is way cheaper than therapy tho. LOL.

And to think I almost washed my work pants last night! Glad I didn't. I like the dust trick, thanks for the tip.

OK, so based on the helpful replies so far, I checked the dipstick with the engine cold. It was covered in oil up to a full inch above the "don't fill" lines. After running the engine at idle for a few minutes and shifting through the gears, I tried again with the pants trick. And see here -- I note the tip is covered but only up to the lowest hole, then a clean dry section, and then it's wet again further up, well above where it should be if filled correctly. Sorry I took a pic of the wrong side of the dipstick, but the other looks similar. I'm thinking the lower reading is the correct one, and I need to add more fluid to bring it up.

Sound right?

 

And the pic...

 

Probably. the upper oil is where it contacted the oil left in the tube and the lower mark is the oil level. normally the oil is checked warm so that will bring it up a slight bit .

What I always do is get the oil level filled properly then I check it cold with the engine off and make a mark there on the stick. it's so much easier to check that way and it's going to tell you if you need to check it again or not.

 

Sounds good, thank you again.

 

In general an auto will read about a quart high when it's cold if it is right on the line when hot. Checking hot is the correct way to be sure, but you could check it cold for the life of the vehicle and as long as it read about an inch high cold, you would never have a problem related to how much fluid was in it. I like to check it cold to get a definitive read on the stick, then check it again hot as a belt-'n-suspenders approach. Your transmission/torque convertor combo holds something like 13 quarts, so don't be afraid to keep adding. You can always suction some out through the dipstick tube if you overshoot. Just don't drive it if it is hugely overfilled.

 

should the truck be running when you check it ?

 

Yes. When I say an inch high on the stick that is with the engine off. ie: "cold". Running, ideally warmed up, is "hot"

 

Thanks, HoustonDave. I am sure I am under-filled currently (I’ve only added 4 quarts since changing the filter, and with the dusty pants trick get the reading pictured above). So I will get it up to the right level hot first, and then experiment with cold readings over the next few days to get a feel for what you are describing.

 

One caveat - the trannie may hold around 13 quarts including refilling the torque convertor. If you did not drain/refill it, you will a) not need near as much fluid and b) have a bunch of old ATF mixed with the new. (There is a cover held on by two bolts at the bottom of the bell housing, remove it, roll the engine around till the drain plug is exposed, drain.)

 

Noted, thanks again.