All Plugged Up
In this particular situation, Dave had been working on a 2001 BMW 740i with a 5HP24 transmission. The vehicle originally came in with a complaint of leaking from the front. The unit was very low on fluid, was slipping and the fluid was burnt. The shop recommended that the transmission be overhauled because of the conditions mentioned and the mileage on the unit. Everything went normally with the rebuild, and the customer left with a properly working unit.
Understanding the AW 55-50 Neutral Control
A 2001 Volvo S60 come into or shop with a smoked AW 55-50 transmission that needed to be replaced.
The AW 55-50 transmission has a feature that Volvo calls “Neutral Control.” What is “Neutral Control” and what is its function? To tell you the truth, I wasn’t really sure, but below is what I was able to both find and figure out about it.
Sometimes Lucky is Better than Good
A mid-’90s Dodge Caravan came into the shop with the complaint of a rough noise/feel when driven above 45-50 mph. The van had been into a couple of other local shops in an attempt to find the noise with no success, and the customer was getting frustrated.
As normal, I started with a road test to see whether I could duplicate the customer complaint. Sure enough, upon reaching 45 miles per hour the van started to make a low growling sound and you could feel a little vibration through the steering wheel. It was time to get the van inside and do a visual inspection.
Hot off the Wire
My first appointment of the day was a customer with a 2001 PT Cruiser. The complaint was, “It feels like the gears are all slipping, and a light is on in the gauge panel.”
I started my evaluation with a fluid check and pulled the codes. The fluid was at normal level, and the code pulled up was P0750 for a solenoid error in the TCM. There were no ECM codes.
Simple Wire Problems
Wow, what a treat I was in for. I brought the Buick into the shop later that day to perform the preliminary checks and noticed that the information center flashed AWD DISABLED, and the message remained on through the entire check-out and road test. I instantly agreed with the customer that this was “bothersome,” to say the least, not really even caring whether the all-wheel drive worked. Just this annoying message on the instrument panel was enough to make a person not want to drive the car, a distraction from an otherwise nice drive.
Chrysler Transmission-Range Sensor
The transmission range sensor (TRS) has three primary functions:
1. Provide a Park/Neutral start signal to the engine controller and the starter relay.
2. Turn the backup lamps on when the transmission is in Reverse and the engine (ignition) is on.
3. Provide a transmission-range signal to the instrument cluster.
Cooler Bypass
External cooler bypass valves are becoming more and more popular, it seems. There are also many different variations of these bypass valves. It’s important that you check the cooler lines and cooler closely to see whether the vehicle you’re working on has one of these bypass valves. In most instances they can be removed and cleaned.
Verify the Systems Before Condemning the Transmission
A few months ago a customer brought in a 2003 Dodge 1500 pickup with a 5.7 Hemi engine and 545RFE transmission. The Check Engine lamp was on and the truck would not accelerate from a stop unless you put the transmission in second gear.
Under Pressure: Sticking solenoid inhibits reverse engagement
With the quantity and price of solenoids becoming a substantial additional investment in the price of a transmission reman, testing and reclaiming the solenoids has become mandatory.
Manual Transmission Fails Because of Hydraulic Error
Manual Transmission Fails Because of Hydraulic Error
R&R Tech
Subject: Shifter sticks in fifth gear
Unit: NV4500
Vehicle Application: 2002 GMC 2500
Essential Reading: Rebuilder, Diagnostician, R & R
Author: Steve Logeman
Why Resistance Checks Don’t Always Work
The example used here is a 1998 Oldsmobile Intrigue 3.8L with a 4T65-E transaxle that has a P0753 electrical code – 1-2 shift solenoid circuit – stored in the PCM; no other DTCs are present. The code will not set until the 1-2 solenoid is commanded to turn on. Now we have all seen the diagnostic flow chart for this code. No matter which repair-service publication you use they are all basically the same: Check resistance from here to here and here to here, from there to there and from here to ground, blah blah blah; I think you know what I mean. Then we print off a wiring diagram so we know what to look at.
Harsh 1-2 Shift
I received a call from one of our wholesale customers, a shop that does general-repair and transmission work on occasion. He was looking for help on a 2004 Ford Freestar that he could not get to leave his shop. In fact, the vehicle had been to several other shops. He told me that another shop had worked on the transmission recently and that it was now back in his shop.
