March 2000 Issue
Issue Summary:
In a GM 4L80-E/4L80-EHD with trouble code 68 in overdrive or trouble code 39 in Drive 3, the cause can be mechanical. The units also have new-design fourth- and overrun-clutch steel plates.
The oil-pump driveshaft in Ford AXOD/AXODE may be the culprit in no movement in forward or Reverse, or no converter-clutch apply at any speed.
We also have updated electrical diagnosis and cautions on 1991-1992 Ford AXODE.
Chrysler 41TE has a change in the overdrive/underdrive reaction plate, as well as a change in the 2-4 low/reverse reaction plate.
In a Honda M24A, no reverse after overhaul may be caused by the bore plug that retains the servo control valve having been installed backward.
Valve-body screens for GM 4L30-E units now are available individually from Isuzu. We list the part numbers for those screens.
February 2000 Issue
This month, we start off with some complaints on Ford 4R44E/4R55E/5R55E units. Delayed engagements and/or slipping may be caused by a missing extension housing lube orifice plug. Insufficient oil to the forward-clutch circuit can cause delayed forward engagement on 4R44E/4R55E units, and no forward engagement in the overdrive range may be because a bore plug in the valve body was installed backward.
A lack of clutch capacity for the overdrive clutch in a Ford E4OD may cause premature failure of the overdrive clutch.
We also have some information on Ford E4ODs with missed shifts that scan tools reveal as “No Codes Present.”
Defective thermostats can cause no converter-clutch applications on Honda Civics and Accords.
January 2000 Issue
Issue Summary:
After TCM replacement on GM diesels, no 3-4 shift or TCC occurs and a code 88 is stored. We explain what caused the code to be set.
GM has made some changes in the PCM on 4L80-E transmissions to eliminate one of the causes of no upshift from first gear.
The malfunction indicator lamp illuminated and DTC P0503 stored on a 4T80-E transaxle may be caused by movement of the final-drive internal ring gear relative to the transaxle case.
In a Chrysler 42RE, a buzzing noise in Reverse may be caused by either a partially clogged main filter or the pressure-regulator valve.
A cracked forward piston or reverse/forward and coast-clutch drum can cause premature coast-clutch failure on GF4A-EL units.
GF4A-EL transaxles with codes 6, 25 and 55 that place the unit in failsafe may require replacement of the PCM.
We also have diagnostic-connector locations and code-retrieval information on GF4A-EL units.
