A/T - 4L60/700R4 Rear Planet Failure/Lack Of Lube

TECHNICAL BULLETIN # 265A (Revised)

DATE: 1996

TRANSMISSION: 4L60/700-R4

SUBJECT: Rear Planet Failure (lack of lube)

APPLICATION: GM

4L60 / 700-R4 Rear Planet Failure (Lack of Lube)

In many cases, the cause of planet failure due to lack of lube can be difficult to find. If you believe that you are faced with a lube problem, check cooler flow before the transmission is removed from the vehicle. There should be a flow rate of approximately one quart in 15-20 seconds from the cooler return (top) line. Cooler flow should be checked at both minimum and maximum TV. If cooler flow is sufficient, remove the transmission and go to step one.

If cooler flow is insufficient at all TV positions, check cooler flow at the cooler out (bottom) fitting. If oil flow is sufficient repair (flush) or replace the cooler as needed. If oil flow is still insufficient, remove the transmission and go to step one. If you do not realize the condition until inspection, follow these procedures to help minimize a repeat of the same failure.


Step 1: Check the output shaft.




Make sure the lube holes in the output shaft are free of debris (figure one). Pay particular attention to the tow holes in the rear journal. These are the lube holes for the rear planet.

Step 2: Check the lube hole for the governor gear.




There should be a .063" orifice inside the visible hole. If the orifice is missing (the hole was drilled all the way through), plug the hole. Now grind a small 'flat' on the journal of the governor that is closest to the gear. Forward clutch oil will now lube the gear.

Tip: the orifice can be plugged by tapping the hole and using an allen-head plug or by driving tow THM 350 checkballs (.250") down the front of the shaft (where the shaft seal goes as shown in figure four.

CAUTION
Do not grind the flat too large 1/16:-1/8" across is adequate.

Step 3: Grind the sun gear.




Grind four small notches into the rear sun gear (figure three). This will offer an additional flow of oil to the base of the pinion gears.

Step 4: Select the proper seal.




There are two lube seals available for the input clutch housing (figure four). Also note that lube oil is fed through a passage in the turbine shaft (figure five). Make sure this passage is free of debris.

Step 5: Check the stator support.







Make sure that the stator support passages are tree of debris (figure six). Also enlarge the converter charge orifice to .110" (figure seven).

Step 6: Grind the pressure regulator valve.




Remove a portion of the center land of the pressure regulator valve as shown (figure eight).

You have just inspected/modified/repaired the entire lube circuit.

The transmission is now ready for assembly and installation. Before the vehicle is delivered, verify that cooler flow is adequate. You should get one quart from the cooler return line in 15-20 seconds. If not repair or replace the cooler.