October 2012 Archives - Transmission Digest
Dodge Caravan’s Sensor Goes Awry

I got a call recently from a friend of mine who runs a car shop, asking for help on a code for a cam sensor.

He had changed the sensor twice and double-checked the circuitry and even replaced the crank sensor. The powertrain control module (PCM) was the next stop, and it was a rather expensive one, so he asked me to take a look at the vehicle before he got a PCM to see if I could verify his diagnosis.

October 2012 Issue

In This Issue
Saturn VT25E CVT
Belt slippage Saturn VT25E CVT
Case damage Allison 1000/2000: Code P0562
Allison LCT1000: Resetting shift adapts

Included in the Quote

Let’s look at an example of what I’ve discussed. Let’s say that you were working on a 2001 Volvo V70 XC AWD, with an AW55-50SN transmission, and the vehicle had been towed in because it suddenly quit moving. You discovered that the transmission had a problem in the final-drive area but you found no other issues. All the clutches were like new, and there was no obvious wear in the valve body etc. That being said, the transmission was probably operating normally just before the final-drive component failed.

What Are You so Afraid of?

Do these customers threaten physical violence if they don’t get their cars fixed at a cheap price? Not usually; if anything they say scary things like “That’s too much money,” “the car’s not worth it,” “I can get it cheaper down the street,” or “I don’t have that kind of money.” Now, if those phrases have rattled you so much in the past that you are now at the point where you drop your price before you even present it to the customer, you are losing sight of a very important point. The customer who would try to negotiate down your price by giving you all those objections would do so no matter what price you started out at. He or she would have fought you no matter what. The problem is that if you started low out of fear, there is nothing more for you to do than go even lower or try very hard to fight off the onslaught of price objections to follow. Starting higher would at least give you some wiggle room if you couldn’t handle every one of their price objections and felt at some point that you would have to negotiate. Then even a negotiated price would be profitable.

62TE: No Reverse

A vehicle using a 62TE transmission comes into the shop with a no-reverse complaint but drives well going forward. Even with the solenoid pack disconnected it still has no reverse but drives forward in failsafe third gear well.

FNR5/4F27E Servo Concerns

A 2-3 shift flare before or after overhaul is a common complaint with the FNR5/4F27E transmission. Even a slight flare can be accompanied by codes for gear-ratio error and solenoid function. The cause for all of this is usually a worn servo-pin bore where it goes through the case.

Dodge 9.25-Inch Differentials, and Why You Can’t ‘Tool’ Around

Repairing differentials is an important source of income for every shop. Many shops had shied away from what is really a simple repair but are now finding that there is not enough work to be had just repairing transmissions. Beside replacing worn or damaged gear sets, you can offer ratio changes that will increase the performance level or lower fuel consumption on many vehicles as an elective purchase for customers who have no problems with the differentials in their vehicle.

The Future of Transmission Specialty Shops

The economy went south, so you tried to figure out what to do. Other shops were doing general repairs. You knew you needed to generate more money so you started selling general repairs too. But was that the right decision for your shop?

It seems like the logical thing to do, but my experiences in a transmission shop tell me not to do general repairs. Too many bad things can happen. I personally do not want to open up that can of worms.

Double Trouble

In today’s world of automatic transmissions we see several different types of solenoids being used depending on the strategy the engineer chose to employ. There are the typical on/off solenoids that could be normally closed or normally open. And then there are PWM solenoids, normally applied or normally vented.