Mike Greer, Author at Transmission Digest
Potential causes of an overheated transmission: It’s not always what you think

If a transmission starts overheating, the root cause must be something to do with the transmission itself, right? Not always. The following are a few examples where the transmission was not to blame. Exhibit A: GM 6L80/90 The first overheating case comes from GM 6L80 and 6L90 transmissions equipped with a thermal bypass valve in

Simple fixes for bad battery connections

In this article we will discuss bad connections, starting with the battery and ending with, well, the battery. Seemingly every week, we at Certified Transmission get a vehicle in that has an issue at the battery terminals; and if it isn’t causing an issue right now, it will sooner or later. All the following cars

You can’t learn everything from a manual: Ram ProMaster City test case

Today’s adventure starts with a customer coming into the shop with a 2015 Ram ProMaster City van with a 2.4L 4-cylinder engine and a 948TE 9-speed transmission. The customer came to our shop because the battery went dead, and after the new battery was installed, a bunch of warning lights came on. The odometer was


Mike Greer breaks down a 42RLE that has trouble leaving park.

A Transmission Problem, Or Something Else?

The subject of this article is a 2007 Nissan Maxima that was brought to us from a shop that we do a lot of work with. They had initially called and wanted to see if we could point them in a direction on what to look at. The shop had stated the vehicle had code P0868 (secondary pressure down), but after the code was cleared, it had not returned yet the car was still acting up.

Programming Not Included

A customer recently brought his 2011 Ford F-150 into our facility after a general-repair shop (not a specialized transmission shop) had just installed a used transmission. His truck was a 4WD vehicle equipped with a 5.0L engine and 6R80 transmission. When the customer picked up the truck from the previous shop he was told that the transmission was installed and everything was fine, but it still needed to be programmed (the shop didn’t have the equipment to perform this important step).

A Very Big Clutch Job for a Very Small Car

My article is going to be a little different this time, and geared more toward the R&R technician. It’s about a car that came to us from a large local dealership that has 13 different locations and works on 14 different makes of vehicles. The subject vehicle is a 2014 Mini Cooper Countryman AWD, with a six-speed manual transmission.

Problem-Free Pickup, Now This: Why?

This month I’m addressing the common complaint of intermittent and erratic torque-converter clutch cycling between 45-60 mph experienced in Dodge Cummins Diesel pick-ups from years 1998-2003. After 60 mph, the issue seems to go away. This has been a well-documented problem over the years with many bulletins published from the manufacturer.

Diagnostic Protocol Saves Time, Money

Anyone who has been in the automotive repair business long enough to remember when repair bulletins were accessible only by either fax or snail-mail can appreciate the ease of access that electronic communication has afforded us in the modern repair environment. More amazing still, is the fact that there are still techs in the industry that fail to seek and use this information to save themselves (and their customers) time and trouble when attempting to diagnose a repair.

Magna Powertrain Transfer Case, RPO Code NQF

We finally had a big-enough snow this year to bring out the people with 4WD problems. This one was a 2008 Chevy Silverado 2500 HD.

It was from a tire distributor that has a number of these particular trucks. Their technicians had been trying to fix the issue of having no 4WD by putting various parts on it. They said that they had replaced the transfer-case motor and buttons.

I started out with the usual road test, scan and lift check to verify the problem. Sure enough, there was no 4WD and the transfer-case control module (TCCM) had every code possible stored. I thought I’d clear the codes and start out fresh.