Transmission Takeaway

Forget about "Right to Repair"; What about the right to rebuild?

"The big problem that maintenance people face--and this is a huge problem--is that each car manufacturer is requiring very specific transmission fluid, and very, very expensive transmission fluid," he explains. "Now, if you have a fleet and you're dealing with all of the same type of transmission, well then that's not so bad; you can get yourself a big, 55-gallon drum and you're good to go, because it's the same fluid for all your vehicles. But if you've got a variety of different transmissions, you've got yourself a problem, because if you do not put the right transmission fluid in, you will have slide shift, bumps, chatters and premature failure of the transmission. It's that critical.

"It's a very high-end synthetic fluid, and the computer controls clutch apply and converter clutch apply in various different ways, where there's a tremendous amount of slip on the clutches," he says. "If the fluid is not right sometimes you can feel the frictions clapping on and off, and it feels like a chatter. The clutch will overheat and burn out, you'll feel it."


So, you've got the proper fluid or fluids for the transmissions in your fleet, and your technicians know which fluid goes with which vehicle. But there's still a problem--actually two problems: no dipstick, and, more often than not, no filler tube.

According to Colonna, this is all in a day's work for a transmission technician.

"You have a standpipe, of sorts, in the bottom pan, and there are various combinations; there's one style where it could be a drain plug as well as a check plug," he explains. "In other words, if you looked at the boot pan you'd see a fairly large nut, and in the center of that nut is another nut, with an allen head. If you took the allen head out, you'd look up inside and there's a tall standpipe, and the fluid level is determined by whether or not the oil comes out over the top of that standpipe. If you took the bigger nut off, then it becomes a big hole in the pan and it becomes a drain plug. And sometimes in order to fill it, you actually have to force oil, or push it, up that little standpipe, until the oil comes out over the top of the standpipe."

If you think that sounds complicated, Colonna also describes a layout where there is a "remote fill location" on the side on the transmission, with an access port that would allow the technician to add fluid until it comes out over the top of the standpipe in the pan.

And there's more: "Some guys maybe will pull a vehicle speed sensor out of the case to gain access through the hole to fill in that way," he says.


With so many different fluids, and so many different methods of checking and filling fluid, a transmission technician needs to be familiar with every type of transmission in the fleet. And, he or she needs to keep track of changes, both big and small, that come with every new model year changeover.

"So it is a can of worms," Colonna says, even though he admits that many transmission shops have reaped the benefits of that can. After all, if a do-it-yourselfer or even a rookie fleet technician can't find the fill tube--perhaps doesn't even realize that there no longer is a fill tube--he or she is going to have to bring the vehicle into a transmission shop.

"But it is a pain in the ass, actually, depending on the carmaker," Colonna says. "Mercedes and Chrysler actually sell a tool to check the transmission fluid level. There is a fill pipe, however on the top of the fill pipe is an actual breather cap. You remove the breather cap, and with this tool--it's really a dipstick, but it's a universal one--you'd be able to check the fluid level of the transmission. But Ford, GM, they have a variety of different ways of checking the fluid level."


In the training sessions that he gives around the country, Colonna meets many technicians who can rebuild a transmission blindfolded but are still stumped by electrical problems.

"They could take a transmission out, repair it and put it back in, and so when there would still be a problem it would go to driveability shops to try to find out if there were electrical issues," he says. "The driveability shop could work it down so far, but then they'd be stumped because they really don't know anything about transmissions."

As a result, driveability issues sometimes end up lost in maintenance limbo: Is it an engine problem or a transmission problem? How can a technician tell?

"It's really a very large subject," Colonna says. "Just to give you an idea, you could have a mass air-flow sensor that's malfunctioning, and the computer's not producing a code for it to indicate a problem with the mass air flow sensor. Not only could it have an effect on the engine's operation, but it also has an effect on transmission operation. It elevates line pressure and now you have extremely hard shifts, later shift points, and the transmission feels like it's the problem, but it's not."

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