TomDirt
FRF Addict
Dipstick tube is straight, Dipstick is fully seated. This looks..... interesting. 
Modifying transmission dip stick
- Thread starter R1jamn
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
I ran into something similar. Also the types of “bends” you make the dip stick take to get there changes the protruding length.
Ruger
FRF Addict
Which is why the instructions read as they do.
Ruger
FRF Addict
When cold, the level of the fluid in the transmission is ABOVE the dipstick opening. Pull the dipstick while the thing is cold, and all of the fluid above that level will pour out. It's a mess worth avoiding.
TomDirt
FRF Addict
Unless you can do it in the neighbor's driveway when they're not home.
Ruger
FRF Addict
And unless they don't have a ring doorbell with which to film you!
I went back and looked at my old posts when I installed the Bm dipstick and I couldn’t find the one I was looking for, but I am 90% sure I installed the new dipstick while the truck was cold and the fluid did not run out.
ATF has a thermal expansion of like 0.0007% per degree C. 70*F to 200*F is ~72*C so that is .0091Quarts per degree C. So cold to hot would be something like half a quart difference.
I don’t know the area of the pan at the level of the dip stick, but I could see half a quart making a difference.
Anyways I’m tired, been a long day and my math may be off as I did it on my phone while watching a movie.
Long story short. I am pretty sure that engine off with transmission cold will not flow out once you crack open the dip stick. Trans hot with engine off will certainly overflow.
Ruger
FRF Addict
It's not that the fluid expands, it's where it is. I am not an automotive engineer and I might be wrong, but I think that when the engine isn't running the torque converter slowly drains fluid into the pan. At any rate, there is a reason why you check transmission level with the engine is hot and running and not when it's cold and not running.
Cheap Experiment: Use your B&M dipstick and check the transmission fluid level in the morning after the truck has sat overnight, and compare it with the reading you get when it's hot and running.
A lot of vehicles that came with a trans dip stick have a hot and cold zone, the cold zone is lower on the stick than the hot zone.
Perhaps letting it sit overnight and not for a few days didn’t allow it to drain down very much, or there is some check valve that prevents drain back. Either way, I’m not sure, I just am pretty sure I installed the stick to do some test fitting when the engine wasn’t running and didn’t have any fluid escape.
My opinion as to why you check the fluid hot and with it running so so that you can get a precise and accurate measurement. I agree it is the correct way to check the fluid level. I would say you have to do it this way since there are more than one configurations with the hoses and coolers. You probably couldn’t get a good fluid level with a dipstick on a cold pan like you can with the oil.
I don’t have the dip stick installed anymore. Had too much trouble getting a good reading on the stick. I do plan to revisit it at some point in the future though.
When I did the trans service last summer, truck sat for a week before dropping pan, let drip for 24+ hrs. When I re-filled only 5 1/2 qts could be added, took Raptor to local ford dealer to check trans level and add more fluid if needed, it took 3 qts more. Conclusion: If you crack the factory dipstick open when cold you could possibly loose 2-3 qts. prove me wrong.
