September 2003 Archives - Transmission Digest
September 2003 Issue

Issue Summary:

No reverse, no 1st and no 4th before and/or after overhaul of a Volvo 50-40LE/50-42LE may result from the solenoid screens being installed upside down during cleaning and servicing of the valve body.

The transmission control module in some Kia vehicles may produce codes for a gear-ratio error, transmission-range-signal malfunction and/or converter-clutch malfunction even though it has not observed incorrect data or any malfunction.

Honda recently released a product update for a problem with the intake air breather pipe and a no-reverse condition on the 2003 Accord.

Plumber’s Helper

This month’s problem/fix comes to us from overseas and concerns the ZF 5-HP-24 transmission. Although this problem has occurred primarily in Jaguars in this shop, it also could occur in other makes using this transmission.

Here is how the symptoms were described to me: The car comes in with a complaint of harsh upshifts and downshifts, no codes are stored, and the transmission is not in limp mode.

KM End-Clutch Failure

Have you ever noticed that most of the complaints or failures you have with a KM involve a burned end clutch? The complaints tend to be sliding 1-2, 2-3 spin-up, neutraling on the 3-4 shift, delayed engagements, no forward or no reverse.

I’ve seen every one of these complaints, only to find the end clutch burned. You might be thinking, “What does a burned end clutch have to do with a sliding 1-2 shift?”

Synchronization: A Study in Timing

Manual-shift transmissions have been manufactured with synchronized gear train for decades. The early designs were three-speed transmissions with 2nd and 3rd gears synchronized, and as transmission design progressed, four-, five- and six-speed transmissions were developed. At this point all forward speeds were commonly synchronized, and as the purchase costs of the vehicles increased and customers became more demanding, reverse was synchronized in most late-model vehicles. Synchronizers remain the most-misunderstood components in manual transmissions and transfer cases and therefore cause a great number of diagnostic headaches and comebacks.

Hot Tech From the Hotline

Have you ever encountered spin-out of the front pump bushing on a Mitsubishi KM unit as shown in Figure 1? Several years ago Paul Yaklin produced a bulletin explaining how the converter pilot bushing would get stuck on the pilot of the converter (see Figure 2). When the converter is removed, the pilot bushing stays with the converter unnoticed. Inevitably, a rebuilt converter then is installed without the adapter bushing in the crank bore. As a result, the centerline of the converter becomes seriously misaligned.