Tighten the bolt by feel
On accuracy and certainty
Two weekends ago, I changed the transmission fluid in my truck for the second time. I did the first fluid drain and filter swap in November 2019.
As part of the procedure, you have to remove the transmission pan to get to the filter. There's a special gasket that goes around the edge of the pan, which also has to come off and be replaced for a leak-tight seal.
There are 22 number of bolts that hold the pan in place. Each bolt is torqued to very light 70 inch-pounds (let's call it roughly 6 pounds of force).
I didn't have a torque wrench the first time I did the job, so I did it by feel.
But this time I wanted to use my itty-bitty inch-pound torque wrench because it promised precision and correctness—even though I hadn't experienced any transmission leaks in the more than 6 years since I changed the fluid the first time.
I started tightening the bolts, crisscrossing all over the pan to make it sit nice and even. I started using the torque wrench, continuing to work slowly across the pan. I watched the gasket as it started to squeeze out ever so slightly between the transmission and the pan, like peanut butter between two slices of bread.
I felt a check in my gut to stop before I boogered up the project. So I did.
I switched over to a small 1/4 ratchet and tightened the bolts by feel. I slowly and carefully tightened each bolt bit-by-bit until they were all snug and happy.
And those bolts have stayed snug and happy. But had I stuck with the torque wrench, I would have easily overcompressed the gasket, which would have definitely caused leaks. I also would have had to drain all the fluid again, get a new gasket, and start that part of the project from scratch—huge waste of time and money.
Pan removed with old filter in place. All old gasket has to be cleaned from the sealing surfaces.
The technically correct value of the torque wrench would have been manifestly incorrect, as evidenced by an improper fix and a leak that could have burned up my transmission.
It's easy to do things by the numbers because it abdicates responsibility: Well, I just did what the book/wrench said. Numbers provide an apparent guarantee of safety and certainty by their exactness.
It's harder to do things by feel because 1.) you have to develop a feel for what you're working on, and 2.) you have to trust your gut.
Trusting your gut is often the safer move.
