Note. Misfiring automatic transmission can be caused by five main causes: engine misfiring, misadjustment, hydraulic malfunctions, mechanical misfiring, or malfunctioning of the computer or its sensors. The inspection should always begin with finding easily fixable problems: the level and condition of the hydraulic fluid (see chapter 1, section 4), linkage adjustment and throttle travel. Then carry out a road test to determine if the problem has been corrected or if further verification is required. If after completion of preliminary checks and repair work the malfunction has not been eliminated, then additional diagnostics must be carried out in the workshop.
Preliminary checks of technical condition
1. Drive the vehicle to warm up the transmission to operating temperature.
2. Check fluid level as described in chapter 1, section 4:
- A) If the fluid level is low, add the required amount of fluid, and then check for leakage.
- b) If the fluid level is excessively high, drain the excess and then check to see if the drained hydraulic fluid contains coolant. The presence of coolant in the hydraulic fluid from the automatic transmission indicates that there is damage to the inner walls of the radiator that separate the coolant from the transmission fluid.
- V) If the transmission hydraulic fluid foams, drain it and refill with new fluid, then check for coolant and see if the fluid level rises.
3. Check up turns of idling. Note. If the engine is intermittent, do not continue the preliminary checks until it has been repaired and is running normally.
4. Check if the throttle cable moves freely. Adjust it if necessary (see chapter 4).
Note. The throttle cable may work normally when the engine is off and cold, and not work properly when the engine is hot. Check its operation when the engine is cold and warmed up to operating temperature.
5. Check shift cable (see section 5). Make sure it is well adjusted and that the linkage works properly.
Checking for Fluid Leaks
6. Most fluid leaks can be easily detected visually. Repair usually consists of replacing the seal or gasket. If the leak is difficult to find, the following procedures may help.
7. Make sure the transmission fluid leaked out, not engine oil or brake fluid (automatic transmission fluid is dark red).
8. Try to pinpoint the source of the leak. Drive the car for a few miles and then stop and place a large sheet of cardboard under the car. After a minute or two, you should be able to find the area of the leak by looking at the stain on the cardboard.
9. Carefully inspect the suspicious node and the area around it. Pay special attention to the mating surfaces of the seals. In places inaccessible to direct inspection, you can use a small mirror.
10. If the leak is still not found, clean the suspicious surface with a degreaser or solvent and dry it.
11. Drive the vehicle for several miles, shifting gears and maintaining normal engine operating temperature. After the trip, inspect the suspicious knot again.
12. After detecting a leak, before making repairs, it is necessary to establish the cause of the malfunction. If you replace the gasket and leave the sealing flange deformed, then the new gasket will not stop the leak. In this case, you must first straighten the flange.
13. Before attempting to repair a leak, check that the following faults have been corrected, as they may cause a new leak.
Note. Some of the faults described below cannot be corrected without experience and special equipment. Such malfunctions should be repaired in a transmission repair shop.
Leakage through gaskets
14. Periodically check the crankcase. Make sure the bolts are tight, none are missing, the gasket is in good condition, and the crankcase itself is not deformed (dents in the crankcase may indicate internal damage to the case).
15. If the crankcase gasket is leaking, it is possible that the fluid level or pressure is too high, the vent hole is clogged, the crankcase mounting bolts are overtightened, the crankcase sealing flange is bent, the sealing surface of the gearbox housing is damaged, the gasket is damaged, or the transmission castings are cracked. If a sealant is used instead of a gasket between the crankcase and the gearbox housing, it is possible that the type of sealant has not been selected correctly.
Leakage through seals
16. If the transmission seals are leaking, the fluid level or pressure may be too high, the vent hole is clogged, the stuffing box bore is damaged, the seal itself is damaged or incorrectly installed, the surface of the shaft protruding through the seal is damaged, or "loosened up" a bearing that can allow excessive shaft movement.
17. Verify that the dipstick tube is in good condition and properly installed. Periodically check the area around the gear or speedometer sensor for leaks. If there is noticeable transmission fluid leakage, check the O-ring for damage. Also, check for leakage from the side shaft oil seals.
Leaks on the hull
18. If the housing began to leak, this means that pores have appeared in the cast parts and the housing must be repaired or replaced.
19. Make sure the oil cooler hose fittings are tight and in good condition.
Leakage of hydraulic fluid through the vent or fill tube
20. If this happens, it is possible that the transmission is overfilled, coolant has entered the transmission hydraulic fluid, porosity has appeared in the case, the dipstick reading is incorrect, the vent hole is clogged, or the drain holes are clogged.