A4LD diognostics,before condeming tranny...

[Fordman]

Before yanking the tranny, here is a list of "should do's" before pulling the tranny. (1) Check fluid level and condition, if it smells burnt, probably ought to try servicing it. A common problem is if it was ever serviced before, the filter o-rings sometimes get left off or cut, leading to hydraulic leakage, or sucking air instead of fluid.(2) Adjust throttle cable, this can affect shift points, and feel, and prolonged driving with it set wrong will toast them quick. (3) Adjust the bands. All A4LD bands, intermediate and od set two turns out , except for the 4.0L, which the intermediate,rear band set two turns out, and od,front band set 3.5 or 4 turns out. I have never confirmed why other than typically 4.0L trannies use a double wrap band, and suspect that if it was rebuild with the single wrap band, it should have the tighter setting.(4) Pull vachum line off modulator, look for raw fluid indicating a failing modulator. If it has been replaced it most likely will be an adjustable model. (5) Make sure the gear selector linkage or cable is correctly adjusted. This is a common cause of an intermittant overdrive, sluggish engagement, and leads to failure. If problems persist, then you need to gather symptoms.

 

[Fordman]

Common leak sources...

A4LD common leak sources are, the well known front seal. Another is the bellhousing mounting bolts, o-rings or gaskets under them can leak, and seem to be a front seal. The modulator can leak fluid into the engine and burn, sometimes creating smoke. The intermediate and od band servo covers on the right side can leak, but this is rare except after an overhaul. The shift lever and kick down lever seal can leak. Check the dipstick tube stub, these work loose and leak. A little locktite sleeve retainer will fix this. Use some engine cleaner and clean the tranny, then watch for the leak source. Overheating, and leaks letting fluid levels to fall frequently seem to be the number one killer.

 

[Fordman]

trouble shooting after preliminaries...

Try to drive it, and figure which gears are having problems. Go to the ATSG manual, there is a map of what tranny componant is used in which gear. Find the componants used in these failing gears, and the common element is usually the problem. This will fairly quickly tell you if the tranny has to come out or can be fixed in the vehicle. I will be the first to say, band servo piston seals, governor weights sticking, and valvebody issues (and gaskets) are about the only in vehicle repairs that can be made.