Up to Standards
In last month’s article we looked over the mechanical functions of the Magna Powertrain 146 transfer case found in the Jeep Grand Cherokee SRT8 model. To review briefly, this model is Jeep’s muscle car and is capable of 0-60 times under five seconds with its 6.1-liter Hemi engine, five-speed automatic transmission and single-speed 146 transfer case.
4F-27-3-Neutral-Hike!
A frequent call we receive on ATSG’s technical hotline with the 4F27E (FN4A-EL) transmission is a neutralizing shift going into fourth gear. The reason why it is such a frequent complaint is that there are several causes of this malfunction.
What is ‘Fretting Corrosion’?
You may have heard the term fretting corrosion recently and wondered what is going on with this odd-sounding phrase. Fretting is defined by Merriam-Webster as “to pass away the time,” but it also means “to gnaw, chew or corrode,” and it is the second definition that can cause technicians to spend too much time experiencing the first. Fretting corrosion can cause time-consuming intermittent failures in a myriad of vehicle systems, and it can be difficult to find.
Just a Bit More Aggressive
Many who sell repair and service work to customers are not, by nature, aggressive types. For the most part they’ve come up through the ranks, first being a technician, then a service writer and now a manager or owner. They tend to have a great deal of sympathy (way too much) for customers who say they can’t have the repairs they need performed now or that they can’t pay the prices being asked and want them lowered. Too many of us think from the customer side of the counter. We tend to put ourselves in their shoes and work very hard to understand their struggle to make ends meet because we know that the economy is not good and that a lot of folks are having trouble getting by.
A Box, in a CAN
One of our customers rebuilt an AW55-50 and had repeat complaints of a 2-3 shift flare. Everything on the transmission side of this complaint was corrected and rechecked. Everything on the valve-body and control side of the complaint was done, checked, verified and looked at again. Resets/relearns – you name it, they tried it. Eventually another valve body was tried, but the car continued to have the 2-3 flare.
BMW X5 Short Circuit
Doing electrical work can be interesting at times, and you never know what you will discover to be the cause of the problem. For example, a customer brought us his 2001 BMW X5 with the 5L40-E automatic transmission in failsafe. Another shop had worked on the engine and told him that the problem was with the transmission. When we checked for codes it had multiple codes in the engine control module (Figure 1).
Valve-Body Reaming
When it comes to reaming valve bodies, there are always questions about how to approach things the “right” way. It pays to keep in mind that reaming a valve-body bore to allow installation of an oversized valve or sleeve is a precision operation and must be viewed with the mindset of a machinist. Properly maintained equipment, correct setup and the right cutting fluids are critical in achieving success. Here are a few suggestions we have compiled over the years in response to common inquiries.
The Hotrod Jeep New Venture Gear 146 Transfer Case
SRT8 stands for “Street and Racing Technology,” which is the performance group of Chrysler Corp, and the 8 signifies a V-8 engine. The SRT people put a whole lot of oomph into this vehicle, designed to compete with the BMW X5 and X6 models and comparable Mercedes-Benz SUVs. Powered by a 6.1-liter Hemi engine, the Grand Cherokee SRT8 is the second-fastest vehicle in the Chrysler line, surpassed by only the Dodge Viper with its V-10 power plant.
July 2010 Issue
In This Issue
Ford/Mazda 4F27E/FN4A-EL: Delayed engagement/low pressure
Ford 4F27E: 2-3 upshift concerns
Dodge/Jeep 42RLE: Low power in reverse
Chrysler/Dodge/Jeep RE-Series Transmission
Issue Summary:
After overhaul, Ford and Mazda vehicles equipped with the 4F27E/FN4A-EL transaxle may exhibit a delayed engagement or a low-pressure condition.
Before or after overhaul, a Ford vehicle equipped with the 4F27E transaxle may exhibit a complaint of a sliding or flared 2-3 upshift.
A 2005-2006 Dodge truck or Jeep with a 42RLE has a lack of power when backing up an incline while loaded or pulling a trailer.
A new governor-solenoid conversion kit is available for the RE-series transmission to improve reliability and performance.
45/545RFE Pump Mystery Solved
This article refers specifically to Dodge trucks equipped with 45/545RFE transmissions. Because Dan’s shop works on many of these units, which are known to have pump issues, he stocks new pumps on the shelf. When Dan called he explained to me that when he disassembled one of these brand-new pumps he noticed that the screws that hold the pump spacer plate to the pump body were missing. He wanted to know whether this could be some kind of assembly-line error and whether he should exchange the pumps for new ones.
‘New’ Does Not Equal ‘Good’
Diagnosis is a challenge for any shop. Sometimes things can get even more complicated because of a previous repair, or a part that has been replaced recently. This case involves both of these scenarios. After all, we really want to believe that a new part is a good one, right?
No Rear Lubrication
A JR403-E transmission from a 1995 Isuzu NPR came in over the counter to Luis Zabala’s transmission shop in Miami for repair of a front-seal leak. The unit was examined for damage because of the possibility of low-fluid-level conditions. The only wear or damage discovered was the pump bushing and seal.
