- A) poor dynamic performance of the engine,
- b) wrong adjustment,
- V) hydraulic failures,
- G) mechanical failures,
- d) failures in the computer or its sensor network.
In any case, the diagnosis of these problems should begin with easy-to-perform actions: checking the level and condition of the transmission fluid (see chapter 1), shift linkage adjustment and throttle linkage adjustment. A road test should then be performed to determine if the problem has been resolved or if additional diagnostics are required. If the problem persists after performing preliminary checks and corrective actions, contact the dealer's service department or a specialist workshop for additional diagnostics. Refer to paragraph «troubleshooting» at the beginning of this guide.
Preliminary checks
1. Drive the vehicle to warm up the transmission to normal operating temperature.
2. Check the transmission fluid level as described in chapter 1:
- A) If the transmission fluid level is too low, add enough fluid to bring the level up to the prescribed range on the dipstick, then check for external leaks (see below).
- b) If the transmission fluid level is too high, drain the excess and then check the drained fluid for coolant contamination. The presence of engine coolant in the transmission fluid in an automatic transmission indicates damage to the internal radiator baffle that separates the coolant from the transmission (see chapter 3).
- V) If the fluid foams, drain it and refill the transmission, then check for coolant in the transmission fluid or if the transmission fluid level is too high.
3. Check the engine speed at idle.
Note. If the engine is malfunctioning, do not continue with the preliminary checks until the problem has been corrected and the engine is running normally.
4. On early models, check the throttle cable adjustment. Adjust it if necessary (see chapter 4).
5. Inspect the shift cable (see paragraph 3). Make sure it is properly adjusted and the linkage works well.
Diagnosis of transmission fluid leaks
6. Most transmission fluid leaks can be easily identified by visual inspection. The repair usually consists of replacing the seal or gasket. If finding the leak is difficult, the following procedure may help.
7. Determine what kind of liquid it is. Make sure it is transmission fluid and not engine oil or brake fluid (transmission fluid, has a dark red color).
8. Try to pinpoint the location of the leak. Drive your car for several kilometers and then park your car over a large sheet of cardboard. After a minute or two, you should be able to find the leak by looking at where the liquid is dripping onto the cardboard.
9. Carefully inspect the suspect element and the area immediately around it. Pay special attention to the mating surfaces, the joints of which are sealed with gaskets. When detecting leaks in hard-to-reach areas, a mirror often helps.
10. If you still can't find a leak, thoroughly clean the suspected area with a degreaser or solvent, and then dry it.
11. Drive the vehicle for several kilometers at normal engine operating temperature, varying the speed. After driving, visually inspect the suspect item again.
12. After identifying the leak, before starting the repair, determine the cause of the malfunction. If the gasket is replaced but the sealing flange remains deformed, the new gasket will not stop the leak. The deformed flange should be straightened.
13. Before attempting a leak repair, verify that the following problem conditions are not present. Otherwise, they may cause another leak.
Note. Some of the following conditions cannot be eliminated without proper special tools and practical experience. To resolve such problems, contact the dealer's technical service department or a specialized service station.
Leaks through gaskets
14. The sump should be checked periodically. Check bolt tightness. Make sure all bolts are in place, the gasket is in good condition and the pan is not deformed (dents in the sump may indicate damage to the valve block located in it).
15. If the sump gasket is leaking, the cause may be too high fluid level or too high fluid pressure, clogged vent, overtightening the sump bolts, deformation of the sealing flange, damage to the sealing surface of the gearbox housing, damage to the gasket, or cracks in the casting of the gearbox housing gears or crankcase porosity. If a sealant was used instead of a gasket as a seal between the sump and the gearbox housing, it could be incorrectly selected.
Leakage through seals
16. If the transmission seal is leaking, the cause may be too high fluid level or too high fluid pressure, clogged vent hole, damaged seal bore, damaged or improperly installed seal itself, damaged shaft surface mating with the seal, or bearing play, which can cause increased shaft movement.
17. Check that the dipstick tube seal is in good condition and that the tube is correctly positioned. Periodically check the area around the speedometer drive gear or sensor for leaks. If fluid is evident, check the O-ring for damage.
Leaks through the crankcase
18. If the crankcase seems to be leaking directly, then the casting has a porous structure and the crankcase should be repaired or replaced.
19. Check that the hose fittings on the heat exchanger are tight and in good condition.
Leakage through the vent or filling line
20. If this condition is observed, the transmission is overfilled, there is coolant in the transmission fluid, the crankcase is porous, the wrong dipstick is being used, the vent or drain holes are clogged.