Transmission Shops: Installation
Understand Systems Involved in Diagnosis

A while back we had a customer come into our shop stating, “The vehicle sometimes has a VSC (Vehicle Stability Control) error and won’t go past fourth gear, but today it seems fine.” The vehicle was a 2007 Lexus LS460 with 132,561 miles, and equipped with an AA80E 8-speed transmission and a 4.6L engine. As with routine diagnosis, I started with a road test, a scan of all modules, and an undercar inspection.

Blame it on Missing Harness Retaining Clips

The subject vehicle that was fitted with one of our remanufactured transmissions six months prior showed up at one of our repair locations recently, with the customer concern of an intermittent bumpy 1-2 shift, and a low-power lugging sensation along with a CEL on. While performing our initial evaluation, we found a P1860 code stored in history, but not current. During the road test the truck was working well with no clear signs of what set the DTC, but after several minutes of driving it started to act up. The TCC was applying right on top of the 1-2 shift, but according to the scan-tool data, was not being commanded on by the ECU.

An ASE Quiz (Not an Official ASE Test Question)

A 1998 Mustang GT shifts good through all gears and has converter lockup, but the speedometer is dropping out after driving a short distance. The scan tool shows that there is a VSS signal and reads correct speed when the speedometer drops out. There was a code in history for the VSS but after clearing it did not return.

Use TSB’s in Your Diagnostic Routine

When diagnosing today’s complex vehicles, we have a wealth of information at our disposal. How we use that information is crucial in making the correct diagnosis the first time, every time. In some cases the diagnosis may be cut and dry (fluid is burnt, the pump is whining, and the vehicle will not move). In other cases, the diagnosis may not be as easy, or worse; we may “think” or “assume” we already know the problem.

Verifying Repairs: This is Where We Dropped the Ball

For this installment of R&R Tech I would like to take some time to discuss how engine performance can affect the transmission operation. We have all heard it before; the engine must be running properly in order for the transmission to function correctly. What does “properly” mean in this scenario? We all use different terms when we tell the customer, “You need to get the engine running properly” or good, correct, better, whatever terms we use; in our minds it all means the same thing.

Get all info the customer has before starting

I have covered some general concerns that have arisen from aftermarket tuning devices and software in a couple of previous articles. I don’t want to sound like I just keep repeating myself, but the problems keep coming through the doors making this an ongoing relevant discussion. I don’t know if it’s just because I am more aware of these issues and maybe look for them more than some folks do, but somehow these vehicles find their way to our shop after the customer has been bounced around from shop to shop before they get referred to us. In this article I am going to cover one specific issue that I had ran into a few months back.

Sensor signal? Nearly none, but unit still worked

The customer had multiple concerns: 30-40 mph is the top speed, drive modes won’t switch, neutrals out in reverse, stuck in low gear at times, can’t shift manually, only works in drive Stored DTC 2767, Component Y3/6n3 (speed sensor) is faulty.

Rats! Foiled Again!

We had a 1998 Ford Contour come into the shop with a transmission wiring harness that had been completely chewed up by mice. I mean every wire in this harness had exposed copper running the length of the harness for at least two feet in one spot, and I can recall at least 10 wires shorting out against each other, causing multiple codes and drivability issues. I asked myself why this mouse (or these mice) would choose to feast on this poor, unsuspecting wiring harness?

Finally, the truck shows its cards

We’ve all had to contend with intermittent electrical problems. These are typically the most difficult issue to pinpoint, as the root cause literally plays hide and seek with you. The following issue that I encountered belonged to a 2008 Dodge Ram 5500 in which the customer stated the transmission wasn’t shifting, and the check-engine light was on.

Accelerating in 4X4 Comes with a Bang

A while back I had a truck that came into our shop for a noise concern. The customer stated that he heard a loud clunk or repeated popping noise when he would accelerate with the truck in automatic 4×4 mode, as well as in 4×4 high and 4×4 low. He also stated that he didn’t notice the noise under light acceleration in these modes, and that the noise was not present when he was in 2WD under any type of acceleration. The truck was a 2009 K1500 Silverado with a little over 83,000 miles on it. Upon reading the description, it sure seemed like I had a transfer case problem to look into.

Checking on Accuracy of Dyno Tests

The focus of this article is the Toyota AB60, as it has a nice balance of five on/off solenoids: S1, S2, S3, S4, and SR. In addition to those, there are 4 PWM solenoids: SL1, SL2, SLT, and SLU, which all operate at about 335 Hz. The test vehicle is a 2008 Toyota Tundra equipped with a 5.7L engine.

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.