Wayne Colonna, Author at Transmission Digest
The differential makes the difference

A 2015 Jeep Wrangler 3.6L using a NAG 1 transmission came into Mr. Transmissions with a third gear ratio code P0733. The shop installed a remanufactured transmission, yet the vehicle still produced this same code. A second reman was put in with the same results. By this time, it was obvious that the transmission could not

Shift Pointers: Sometimes, a repair needs a little more push

An interesting scenario recently took place with a 2014 GMC Sierra 2500 using a 6L90 transmission at Harry’s Transmissions. After rebuild, the vehicle had a no-start condition. Harry attached a scan tool and discovered there was also a no communication issue with the TEHCM. This brought him to the harness connector to do a quick

10R80 aches and pains: Unintentional park hold

The Ford 10R80 is a unit that visits specialty repair shops on a frequent basis with a variety of aches and pains. The automatic transmission specialist has diagnosed various symptoms that have become common ailments with these transmissions. The CDF cylinder sleeve moving out of position is one of these disorders (see Figure 1, above). 

Shift Pointers: A 10R140 with a classic drivability complaint

A 2021 F-350 6.7L Super Duty using the 10R140 beast of a transmission recently came into Precision Auto Repair not upshifting when pulling a load only. On light throttle it would upshift, but not as high as tenth gear. Once the throttle was depressed it would downshift and no longer upshift. It displayed similar symptoms

Figure 2.
The Subaru mystery burn

The Subaru TR580 transmission is known for having torque converter clutch solenoid failures. An example of this can be seen in Figures 1 (above) and 2 (below). The solenoid resistance should be between 10 to 13.5 ohms. The resistance right at the solenoid itself on the valve body is close to 38 ohms. And as

Shift Pointers: Where’s that fluid leak coming from?

A 2016 Honda CRV 2.4L (Figure 1), using a BLJA CVT 4WD transmission (Figure 2) comes in to a shop with a customer complaint of a leak. Before anyone checked fluid levels, the vehicle was hoisted up for a look. A visual inspection revealed a leak coming from between the transmission and the engine. The

Chrysler RH/RE late shifts and high pressure

You may find that these transmissions have a late 1-2 and 2-3 shifts along with high TV/line pressure.

Ford 6R80 shift solenoid ‘E’ resistance change: How to tell the difference

The lower resistance and higher resistance solenoids are not interchangeable.

Allison 1000 geartrain bind-up

When the torque converter housing is bolted to the transmission case in an Allison 1000, the geartrain is locked and will not rotate.

How to get around non-serviceable GM 6T70/75 self-tapping pump screws

General Motors designed the 6T70/75 transmission fluid pump to be a non-serviceable component.

Figure 1.
Ford 8F24 mechanical diode failure

Mechanical diode failure in automatic transmissions is not uncommon. As far back as the AODE/4R70 shops have seen this type of failure. In April 2022 an article was published in Transmission Digest called, “The ins and outs of the Hydraulic Selectable One-Way Clutch (SOWC).” This article provided photos of the type of damage this style

Sometimes, a diagnostic code is all you need

With ATSG having the opportunity to help shops solve problems, sometimes we get faced with some real doozies. A shop will call and give us a laundry list of DTCs, leaving us to think someone must have a bulkhead connector unplugged. We then go through the arduous task of deciding which codes prompted other codes