Jeep Grand Cherokee started using the 42RE transmission in 1993 1/2 models with the 4.0L engine. The "4" stands for 4-speed, "2" is for torque capacity, "R" is for rear-wheel drive, and "E" is for electronically controlled.
This transmission is electronically controlled using a governor pressure solenoid to vary the governor pressure. The shifts are controlled by the valve body by conventional shift valves for 1-2 and 2-3 upshifts. The 3-4 upshift and 4-3 downshifts are controlled by a solenoid. Although the shifts are controlled by shift valves for the lower gears, the higher gear is electronically controlled because the governor pressure acting against it is controlled by the transmission control module (TCM). The throttle pressure is controlled by a standard cable and throttle valve. The TCM inputs for this system include engine rpm, throttle position sensor, vehicle speed sensor, transmission output speed sensor, governor pressure sensor, transmission fluid temperature sensor and overdrive "off" switch. The TCM outputs are the 3-4 shift solenoid, the governor pressure solenoid and the torque converter clutch solenoid.
Here's how this system operates: As the output shaft begins to move, a 2-wire AC generator (transmission output speed sensor) begins to signal the TCM of the rpm. As the shaft speed increases, the TCM controls the governor pressure solenoid accordingly by a pulse-width modulated signal. Feedback to the TCM is provided by a governor pressure sensor to verify that the pressure actually changes. The pressure sensor is a 5-volt reference sensor. When the wheels are not rotating, voltage around 0.6 V is normal. As the wheels begin to speed up, the voltage should increase proportionately. If the voltage does increase, then the pressure is increasing as it should - this should be verified with a pressure gauge. This variance of pressure acts upon the shift valves in the valve body along with the throttle pressure to provide the shifts. As speed warrants, the TCM will apply the 3-4 overdrive solenoid, which is the only shift solenoid used on this system. The OD inputs are overdrive off switch, TPS, VSS, transmission temp sensor, output speed sensor and engine rpm. The torque converter clutch (TCC) solenoid will normally operate in overdrive, but the TCM can operate the TCC in third gear if the overdrive off switch is selected. Inputs for TCC include OD off switch, TPS, engine rpm, VSS, output speed and transmission temperature sensor.
The transmission temperature sensor is mounted on the overdrive/torque converter clutch solenoid assembly and provides input to the TCM. When the temperature sensor reports 30 degrees F or colder, there will be no overdrive, and below 50 degrees F, there will be no torque converter clutch. If the transmission fluid temperature sensor reports an overheating condition (over 260 degrees F) and the transmission is currently in overdrive, the TCM will downshift to third gear. The TCM will also light the LED in the dash-mounted OD off switch until the temperature drops below 230 degrees F. However, the torque converter clutch may still be operational.
This system has self-diagnostics. Fault codes can be read with a scan tool or by cycling the ignition key three times, then counting the flashes of the LED in the OD off switch. The diagnostic connector is located inside the vehicle to the left of the center console. The default mode of the TCM is third gear. Manual shifting of reverse and second gear is possible when in default mode. Default mode happens after a fault code is set.
yeah I saw that page yesterday and thought about sending it and some wiring schematics to Brett at awshifting so maybe he could make a kit for us
Not really a crappy trans, just not great in stock form.
The A500/A518/904s are all based off the 727, which is a great trans. I would rather have the A500 than an A4OD.
If you think it is the crappiest then you sir are lucky as there are a lot worse out there.
ok well maybe not the crappiest, but its deffinatly not the best
Not a bad trans, just not a long life....I guess that wasn't much of an issue back in the glory days of the TF727 (The 1960s and early 70s), when a car was ready for the crusher at 100,000 miles.
But they certainly don't have the reliability of other slushboxes, notably GM's. Of course, I can't get over the fact that between the valve body and the case there's NO gasket.
Makes a great paper weight imo.
I'm not overly pleased with my 46RH so far. We'll see after a cooler, new filter and some AMSOIL.
The 500, electonic 42s and 44s are based on the old 904 and 999 Torqueflites.
The 518, electronic 46s, 47s and 48s are based on the 727 Torqueflite.
IMHO, these are good trans. We, as Jeep enthusiasts, are doing things with them that they were never meant to do. With regular maintenance, I have put hundreds of thousands of miles on them without a failure. In fact I have owned more than 10 Mopars with these trans. Not one has failed. Some went more than 500,000 KMs. I can tell you many horror stories about some other makes of trans that I've owned or had experiences with. Most of the problems that I have seen with Mopar trans are cased by lack of maintenance and/or wrong fluid. Anything other than street driving any auto trans should have a shift modifier installed and regular fluid and filter changes and band adjustments. With this done the Mopar trans will last a good long time.
My uncles zj's trans shit the bed under 36,000 still under warranty his is stock and he is mellow. Mine has been rebuilt once and is crashing again with a sick wine in overdrive this is one reason my zj will have a chevy powertrain
This could get into a real pissing contest about makes. With that said, I've been a high mileage driver for many years and have owned or been assigned to several different brands both foreign and domestic. They all have their horror stories. I can tell you about the drive train problems in Chevy trucks. Talk about a shitty trans, try a GM 350 or a 700R4. We had a standing order at the local wreckers for those things. The owner of the company was a Chevy guy and even he got tired of paying the repair bills. Any way this is a debate that no one wins. It has gone on for ever and will continue. We used to call it bench racing.
All electronic trans are prone to problems, just check out some of the other makes forums or walk through a dealer service department.
Build an automatic with the correct HP components and maintain them and they will last a good long time. Without at least a shift improver, a big cooler frequent fluid and filter changes, and adjustments, an automatic is a boulevard cruiser. IMHO.
Amsoil will solve nothing, and regarding these trans may infact add to the problems.
Doubt it. Amsoil is good stuff.
Just I can't afford $7 a quart when I pay that for a gallon of normal stuff.
Amsoil is only good for use in Fires that stuff SUCKS Hands down...
WRONG thing to say, especially when reviving a thread
Hi all, i have a 93 grand with a 42re,4L. motor.And im lookin 4 a replacement trany.Does it have to be a 93-98 year or can i look4 a newer 42reto replace it.
http://www.idatc.com/application_page.htm#jeep says it good too 2000? thax 4 any reply. bob
sorry 2004 instead of 2000
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