August 2010 Archives - Transmission Digest
604 Solenoid-Block Mystery Leaks

The 604/41TE has been around for some time and we are all pretty familiar with it; however, some things still pose a challenge on this transmission, and one of them is leaks.

August 2010 Issue

In This Issue
ZF 5HP24: Chronic front-seal leak
ZF 5HP24: Neutralization; chatter
2003-04 Range Rover ZF 5HP24: Late shifts, neutralizing
45RFE & 545RFE: Assembly tip

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.


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).