June 2004 Archives - Transmission Digest
Ford 4F27E Shift Strategy – a Different Way of Doing Things

The 4F27E transmission uses two on/off solenoids and three PWM solenoids to produce each of the shifts and converter-clutch apply, as the chart in Figure 1 shows. The EPC solenoid is used to control line pressure relative to engine torque. So far this sounds easy, but from a strategy standpoint, it progressively moves toward a “different way of doing things” when compared with what we are accustomed to.

Mastering the Mysteries of Synchronizers

In a transmission we have a sequence of events that must take place in a precisely timed manner to get a smooth, effortless, clash-free shift. Let’s follow these events to understand the theory of operation and with that knowledge find the solutions that will fix and prevent further shift problems.

4T65-E’s and the Mysterious Code P0730

A 2001 Buick Century Custom came to a transmission shop with a complaint of jerky shifts. A road test of the vehicle showed that all shifts were harsh, and a scan check registered the generic gear-ratio-error code P0730. Since code P0730 does not illuminate the malfunction-indicator light, the harsh shift was the customer’s only clue that anything was wrong.

June 2004 Issue

Issue Summary:

Some 1997-2002 vehicles equipped with the 4T40-E or 4T45-E transaxle may exhibit harsh engagements and/or harsh upshifts and may have trouble codes PO112, PO113, P1111 and/or P1112.

Since the introduction of the THM 4T40-E transaxle in 1995, there have been three different design levels of the accumulator springs and their locations.

Some 2003-model THM 4T65-E transaxles come equipped with a newly designed input and third pawl-clutch assembly instead of the previous-design input and third sprag clutch.

Beginning in June 2002 Hydra-matic changed the design of the oil-pump assembly on 2002 and 2003 models of the 4T65-E transaxle.

Rich or Poor, It’s Nice to Have Money!

When you have money, you’re in control. When you don’t, other people are in control of you. You work because you owe. That is never a comfortable position to be in. Cash is king. When you have it and others don’t, you can compete on a higher plane.

I See It, But I Don’t See It!

Incorrectly installed 4T65-E internal mode switch causes shift problems

I got a call from a technician who was working on a 4T65-E. It seems that after the freshly rebuilt transmission was re-installed, the car would not start in park or neutral and the transmission would make a wrong-gear start and shift only once. I came to find out that this was not an original problem, which means it was created during the repair process.