Technically Speaking
- Author: Wayne Colonna, Technical Editor
The R&R Person’s New World
I could only imagine the thoughts that ran through the minds of R&R men after they lifted the hood to view the Cadillac North Star/4T80-E combo for the first time. Perhaps it was something to the effect of, “Where is the transmission?”
But after a few minutes of scrutinizing the situation, they may have elevated their thoughts to an audible comment something like: “You have got to be kidding me! Am I supposed to get that thing out of the car? It looks like the body was molded around the engine and transmission during assembly. The only way that thing is coming out is with the use of a carbide saw blade and the jaws-of-life combination, and those tools I do not have so someone else will have to do it!”
People comment frequently on how the changes in the auto industry and its technology accelerate with discomforting speed. Very little, however, is ever mentioned about changes that affect the R&R person (or Re & Re, as they say in Canada). The level of difficulty in removing and installing transmissions as compared with the early ’90s has increased significantly. Not only are some of these transmissions buried tightly into the body or engine compartment, but they also are of enormous size with awkward weight distribution. These types of transmissions give “Transmission Jack Agility” a whole new meaning. Much care and attention are needed in removing these beasts so as to prevent damage to other parts of the vehicle and to human parts.
Those who do this type of work and do it well should be given their due recognition. Not only is it tough physical work, but it also takes a thinking person to maneuver the removal process successfully. Any shop owner can appreciate this, especially after the job has been sold. Now the transmission is on its way back in when suddenly there is a snapping noise. All eyes of hope move to the location of the sound, praying that what may have broken is not too disastrous. Unfortunately, more times than not, what is discovered reveals that those few seconds of hope were only wishful thinking. What would be discovered for example would be a $200-plus platinum-tip heated oxygen sensor shattered into pieces.
One day as I was pulling up to the shop’s garage door, returning from a road test, I observed an R&R man letting down a KM unit from a Gallant. He was talking with another R&R guy and had his head turned away from the transmission. Before you knew it, I saw what looked like the transmission lifting off the jack. What actually happened was that the solenoid wiring harness got entangled somehow with the inhibitor-switch assembly. The jack lowered itself under the transmission, and the transmission started to dangle from the wiring harness. The R&R man noticed what was happening before the entire weight of the transmission was swinging by wires.
Without question, R&R mistakes can be absolutely costly and devastating. But the only training an R&R guy gets is experience, and sometimes it can be a bad experience that helps him to be better the next time. Although this may be a form of learning, providing education on a less-expensive learning curve would be most desirable.
In light of that, Transmission Digest will feature R&R articles and tips periodically. John Parmenter, an owner/rebuilder of a shop that does considerable dealer work and a member of the advisory board for Precision International, will be a contributing editor in this regard. He started with a basic introductory article in last month’s issue of TD. Up and coming, he will be providing comprehensive tips on removing the 4T80-E transaxle from Cadillac’s North Star engine. He also will cover transmissions including the 4L60-E from both the Corvette CS design level and AWD Chevy vans, and the AWD CD4E in Ford’s Escape vehicle.
We also have invited DriveTek, a Transmission Training Academy for both the R&R man and the rebuilder (http://www.drivetek.net), to provide R&R tips. With this lineup of qualified contributing editors, it is our goal is to be the first with consistent, helpful information for the R&R world.
As for this article, the following R&R tips could save you thousands of dollars. These tips are best learned right here and not by experience.
During removal of an R4A-EL transmission from a Mazda 929, it is not uncommon for the heated oxygen (O2) sensor to become unplugged from the exhaust system. The connector for the O2 sensor can be easily cross connected with the transmission’s turbine-shaft speed (TSS) sensor during installation. Should this occur, as soon as the vehicle is started, the voltage sent to the O2 sensor returns to the TCM on the TSS-sensor wiring. The result is a meltdown of both the PCM and TCM wiring harnesses and computers. The cost of repairing this will run into the neighborhood of $3,000.
Figure 1 shows the TSS sensor on a Mazda 929 R4A-EL transmission. Figure 2 shows how both the TSS sensor and O2 sensor have connectors that allow a cross connection. The tip here is that the TSS sensor has three wires in the connector and the O2 sensor has four. You’ll want to get these connected right the first time.
Another area to watch for involves GM’s 1999 Oldsmobile Intrigue 3.5-liter DOHC V-6 (VIN H) engine with a 4T65-E transaxle. The No. 1 bellhousing bolt in this application is 2 millimeters (5⁄64 in.) shorter than any of the other bellhousing bolts (see Figure 3). Should you install one of the longer bellhousing bolts in this location, it will penetrate an oil passageway in the back of the engine block, damaging the block and causing an oil leak between the engine and transmission.
One more tip: Mercury Villager and its twin sister, the Nissan Quest, use the same transaxle. A ground strap is attached to a stud just above the servo by the filler-tube retaining bracket. If you forget to attach this ground strap, as soon as you cycle the ignition the TCM becomes a very good door stop.
The R&R facet of the industry clearly is a tough job, and doing it right takes talent and knowledge. And for all of you who do, you have my utmost respect. I trust that the articles to come will be of great value to you, giving your work the attention it deserves.
