The 722.6 Shift Strategy
With the 722.6 being a transmission that shifts from clutch to clutch, smooth shifting requires proper shift overlap. To accomplish this task, a number of components and strategies merge to allow for adaptation under various driving conditions. To fully appreciate what it takes to make for correct shift timing and shift feel, it is good to look at and understand these components and strategies independently. And after having a basic understanding of them, one can see how they work together like members of a musical band to harmoniously accomplish the task at hand.
February 2005 Issue
Issue Summary:
A 1993 or later Chrysler front-wheel-drive car or van may have a complaint of no speedometer operation and may have all the PRNODL lamps illuminated.
Some 1999-2000 vehicles equipped with the 42RE/46RE may exhibit a harsh engagement in reverse.
A 1996 or later Jeep or Dodge truck with an RE transmission may exhibit complaints of falling out of 4th gear and loss of TCC application. On diesel applications, the transmission may be stuck in 3rd gear and governor pressure may be 70 psi in Park.
Solving Difficult Problems: Think Outside the Box
It is easy to lose one’s way and become embroiled in solving problems that actually do not exist. This is where the development of a proper diagnostic method of thinking a problem through before actually turning a wrench is a must. We as technicians are always guilty of attacking the unit when any number of external forces can create the problem that has shown up while it’s under warranty.
Chrysler 41TE & 42LE Range Sensors
Have you ever been here? It’s late in the day (usually Friday), and you’re just about to button up the 41TE or 42LE job you promised. Everything is going as planned. You go to plug in the range sensor, only to find out that the range-sensor pins are different and the vehicle harness won’t plug in.
False Pretenses
A 2002 Ford Explorer with a 5R55W transmission came into a shop with a complaint of no 2nd or 5th gear. Gear-ratio-error codes P0732 and P0735 were stored, but so was code P0775, indicating a problem with pressure-control solenoid B.
We all know what gear-ratio-error codes are all about by now, but that P0775 code – that’s a humdinger.
January 2005 Issue
Issue Summary:
Some 2000-01 Dodge Ram Vans, Dakota and Ram pickups, and Durango SUVs with 46RE/47RE transmissions may exhibit a flashing Check Engine light, caused by diagnostic trouble code P1740 (torque-converter-clutch or overdrive-solenoid performance fault).
Before and/or after rebuild, vehicles equipped with Chrysler 47RE transmissions may exhibit soft TCC apply or repeated TCC failure.
A previously repaired Ford Motor Co. vehicle with the AX4S/AX4N transaxle may exhibit a feeling of surging with a complaint of engine-speed fluctuation during lockup application, followed by a noticeable “bump” at the end of lockup engagement.
Where Do We Go from Here?
The start of a new year is a time for reflection on the current state of business and a time to formulate a business plan for the next 12 months. For most shops in our industry the past few years have been difficult, and many have closed, sold out or changed the way they do business. Twenty-some-odd years ago there were about 24,000 transmission shops in the country, and at this point the latest estimates are less than 10,000 shops that do nothing but transmission work. This is consolidation on a grand scale.
P1870 Revisited
Just when you thought you had all the P1870 torque-converter-clutch slip codes under your belt, another vehicle comes along – and here we go again!
AFL and AFL
AFL stands for actuator feed limit and another fourth lost.
Perhaps you’ve already chased this on a 4L80-E or in a somewhat similar fashion on a 4L60-E. Here’s how badly it can go. You take in your buddy’s 4L80-E with converter codes and failsafe operation beginning to appear at normal mileage. Make it worse: It’s a good buddy, so you give him a break on the price. You scan the unit, drive it, do a careful rebuild, check TCC-related areas, put in a good converter, fill it with your preferred red fluid and reset the computer.
A Blast from the Past
Today, we have a similar problem with welds cracking in General Motors’ 4T40-E oil-feed-tube assembly (see Figure 1). Lube failure to the forward-clutch-support assembly, slipping or no reverse, loss of engine braking in manual low and slipping or no forward are all possible with weld failure of the oil-feed-tube assembly.
‘When I Says Woe, I Means Daewoo’
A 1999 Daewoo Leganza with a 50-40LE transmission came into the shop with the driver complaining that the vehicle had no power. It was immediately discovered that the transmission was in a fourth-gear limp mode. The next step was to retrieve codes. The aftermarket scan tool the shop owns does not offer a specific Daewoo cartridge, so only generic OBD-II was available to them. And as you probably guessed, the scan tool reported that no codes were present.
December 2004 Issue
Issue Summary:
Before and/or after overhaul, 1995-2002 vehicles with 4R44E/55E or 5R44E/55E transmissions may exhibit soft or flared shifts, multiple gear-ratio-error codes or solenoid performance codes.
Some vehicles with 4R44E/4R55E/5R55E transmissions may exhibit delayed engagement in reverse and no engine braking in manual low.
Ford or Mazda vehicles with 4F27E or FN4A-EL transaxles may exhibit DTC P0741, torque-converter clutch stuck off, before or after overhaul.
Ford or Mazda vehicles with 4F27E or FN4A-EL transaxles may exhibit delayed forward engagement or premature forward-clutch failure.
Before or after overhaul, Ford vehicles with the 4F27E transaxle may exhibit failure due to lack of lubrication.
