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

A mysterious shudder: Locating a problem with no fault codes
It was a dark stormy night… well, not really; it was just an ordinary Tuesday. On that ordinary Tuesday, a customer came into our store very distraught. He had been to several shops with concern of feeling a shudder while driving his vehicle uphill. None of the other shops or the Toyota dealership could give

TCM trouble and the importance of being certain about parts replacement
It’s a tale as old as time. A vehicle comes in and, despite having been recently repaired by another shop, the vehicle owner’s concern is still present. In the case of this story, the vehicle came from a local shop we work closely with. The truck in question is a 66,000-mile 2006 Chevrolet Silverado 2500

Scope testing the Ford 10R80
Recently, we at Certified Transmission had a chance to do some work with the Ford 10R80. We have easy access to test vehicles since our owner also owns a used car dealership. For our R&D testing we used a 2019 F-150 equipped with a 5.0L engine and the 10R80 transmission. I got to play around

Diagnosing an unusual problem: A slow-to-respond solenoid
A 2001 Chevrolet S-10 pickup came into our shop the other day. This job started with a concern of the engine revving high and not shifting correctly. With the truck being equipped with a 4L60E transmission, I expected to find non-functioning third and fourth gears, which is a common failure for these transmissions. I scanned

The Nightmare on Oak Street: A hunt for 4L30E electrical problems
This story begins with a 4WD 1998 Honda Passport equipped with a 3.2 V6 engine and 4L30E transmission. The shift indicator in the cluster was not functioning correctly and transmission was shifting hard. The shift indicator showed ‘P’ in Park, and ‘1’ in D3, D2, or D1. The indicator didn’t light up in any other

How do you know if a car is lying to you?
Sometimes a vehicle comes into the shop with a code in memory and a concern, and it is quick and easy to follow the code and find the source of the problem. But how do you know if a car is lying to you, trying to throw you off the trail with some false information?

Putting what you learn in training into practice
We all have those family members and loved ones who need our help and expertise when it comes to cars, and I am no exception. I purchased a 2001 Honda CRV AWD with a possibly bad transmission for my daughter to replace the worn-out vehicle she was driving. After determining that the transmission was indeed

An accidental solution: When an issue resolves itself, but you don’t know why
Today I found myself working on a 2008 Chevy Silverado with a 4L60E transmission that wasn’t shifting correctly and whose speedometer was jumping around. After a short drive I was able to confirm the customer’s concern that the transmission had an erratic shift. I have seen faulty alternators that cause erratic speedometers, so I did

It’s the little things: Double-checking and doing the basics in transmission repair
As transmission technicians, problem-solving is what we do. We see that box that says “customer states” and we already have an idea of what is wrong, and 99% of the time we’re right. After all, it’s the eighth 6L80 we have seen this month. But with an endless list of components and ever-evolving technologies it

Mystery transmission problems: When the code doesn’t match the complaint
This one was a learning experience for me, and I hope my journey will help others if they run into this same scenario. A 2012 Nissan Quest with a 3.5L engine and the RE0F09B transmission came into our shop with the complaint that the CEL was on, there was a loss of power and the

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
