Mazda Trucks 1987-1993 Repair Guide

Automatic Transmission

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In 1987, a 3-speed lock-up torque converter version of the 3N71B was introduced. Its designation is L3N71B. It was offered only on the B2200. Aside from the lock-up feature, the main difference lies in the fact that there are no band adjustments. This unit continues on the B2200 through 1988.

Also in 1987 a 4-speed unit was offered as an option on the B2200 and as standard on the B2600. It is designated L4N71B. This unit continues through 1988.

In 1989, only the L4N71B is offered on pick-ups.

From 1990, the N4A-HL 4-speed is used on all pickups.

The MPV is equipped with a 4-speed unit designated N4A-HL. An optional, electronically controlled 4-speed is available. Its designation is R4A-EL.

4-Wheel Drive MPVs use the R4AX-EL, which is essentially the same unit as the R4A-EL.

The Navajo uses a Ford A4LD 4-speed unit.

FLUID RECOMMENDATION



All automatics use Dexron®II ATF.

LEVEL CHECK



See Figures 1, 2 and 3

  1. Drive the vehicle for several miles to bring the fluid level to operating temperature.
  2.  
  3. Park the truck on a level surface.
  4.  
  5. Put the automatic transmission in PARK. Leave the engine running.
  6.  
  7. Remove the dipstick from the tube and wipe it clean.
  8.  
  9. Reinsert the dipstick so that it is fully seated.
  10.  
  11. Remove the dipstick and note the reading. If the fluid is at or below the Add mark, add sufficient fluid to bring the level to the Full mark. Do not overfill the transmission. Overfilling will lead to fluid aeration.
  12.  



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Fig. Fig. 1: Automatic transmission fluid level dipstick is located on the right side of the engine in the rear of the compartment-MPV shown



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Fig. Fig. 2: Automatic transmission fluid level dipstick measurement-Fluid level should be between the two arrows



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Fig. Fig. 3: Use a funnel (to avoid spills) and add the required type and amount of ATF

DRAIN AND REFILL



See Figures 4 through 11

The automatic transmission fluid is a long lasting type, and Mazda does not specify that it need ever be changed. However, if you have brought the truck used, driven it in water deep enough to reach the transmission, or used the truck for trailer pulling or delivery service, you may want to change the fluid and filter. It is a good idea to measure the amount of fluid drained from the transmission, and to use this as a guide when refilling. Some parts of the transmission, such as the torque converter, will not drain completely, and using the dry refill capacity listed in the Capacities Chart may lead to overfilling.

  1. Drive the truck until it is at normal operating temperature.
  2.  
  3. If a hoist is not being used, park the truck on a level surface, block the wheels, and set the parking brake. If you raise the truck on jackstands, check to see that it is reasonably level before draining the transmission.
  4.  



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Fig. Fig. 4: Using a 10 mm socket, remove the transmission oil pan bolts except for one mounting bolt at each corner



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Fig. Fig. 5: After removing the rear corner pan bolts, carefully lower the pan by hand, making sure that a minimal amount of trans fluid spills out and soaks your arm



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Fig. Fig. 6: Lower down the transmission oil pan

  1. There is no drain plug, so the transmission pan must be removed to drain the fluid. Carefully remove the screws from the pan and lower the pan at the corner. Allow the fluid to drain into a suitable container. After the fluid has drained, remove the pan.
  2.  
  3. The filter is bolted to the lower valve body. Remove the filter attaching bolts and remove. Clean it thoroughly in solvent, if it is a screen type, allow it to air dry completely, and replace it. Tightening torque for the attaching bolts is only 24-36 inch lbs. (3-4 Nm), so be careful not to overtighten them.
  4.  



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Fig. Fig. 7: Once the pan is removed, discard the old gasket and insure that the mating surfaces are clean



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Fig. Fig. 8: Remove the O-magnet from the bottom of the transmission oil pan and clean it of any dirt or small metallic fragments using a towel



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Fig. Fig. 9: Remove the four transmission oil filter mounting bolts using a 10mm socket



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Fig. Fig. 10: Remove the transmission filter from the trans valve body. Be sure that the O-ring seal also comes out with the filter



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Fig. Fig. 11: Install a new pan gasket

  1. Remove the old gasket and install a new one. The pan may be cleaned with solvent, if desired. After cleaning, allow the pan to air dry thoroughly. Do not use a rag to dry it, or you risk leaving bits of lint in the pan that will clog the transmission fluid passages. When the pan is completely dry, replace it, and tighten the bolts in a circular pattern, working from the center outward. Tighten gently to 40-60 inch lbs. (5-7 Nm).
  2.  
  3. Refill the transmission. Fluid is added through the dipstick tube. This process is considerably easier if you have a funnel and a long tube to pour through. Add three quarts (2.8 liters) of fluid initially.
  4.  
  5. After adding fluid, start the engine and allow it to idle. Shift through all gear positions slowly to allow the fluid to fill all the hydraulic passages, and return the shift lever to Park. Do not race the engine.
  6.  
  7. Run the engine at fast idle to allow the fluid to reach operating temperature. Place the selector lever at N or P and check the fluid level. It should be above the L mark on the hot side of the dipstick. If necessary, add enough fluid to bring the level between the L and F marks. Do not overfill the transmission. Overfilling will cause foaming, fluid loss, and plate slippage.
  8.  
  9. After a few days of running, check the pan bolts. They will, probably have loosened as the gasket has shrunk. Retorque them.
  10.  

 
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