1945 Jeep FLUIDS AND LUBRICANTS
Fuel and Oil Recommendations
FUEL
All models through 1970 are designed to use a regular grade of gasoline.
ENGINE OIL
Fig. 1: A label on the oil container will provide important information about the oil
Many factors help to determine the proper oil for your Jeep. The big question is what viscosity to use and when. The whole question of viscosity revolves around the lowest anticipated ambient temperature to be encountered before your next oil change. The recommended viscosity ratings for temperatures ranging from below 0°F (–18°C) to above +32°F (0°C) are listed in the accompanying chart. They are broken down into multi-viscosities and single viscosities. Multi-viscosity oils are recommended because of their wider range of acceptable temperatures and driving conditions.
The SAE grade number indicates the viscosity of the engine oil, or its ability to lubricate under a given temperature. The lower the SAE grade number, the lighter the oil. The lower the viscosity, the easier it is to crank the engine in cold weather.
The API (American Petroleum Institute) designation indicates the classification of engine oil for use under given operating conditions. For gasoline engines, only oils designated for Service SE/SF, or just SF, should be used. You can find the SE or SF marking either on the top or on the side of the container. The viscosity rating should be in the same place. Select the viscosity rating to be used by your type of driving and the temperature range anticipated before the next oil change.
The multi-viscosity oils offer the advantage of being adaptable to temperature extremes. They allow easy starts at low temperatures, yet still give good protection at high speeds and warm temperatures.
Engine
OIL LEVEL CHECK
Make sure that your vehicle is on a level surface to ensure an accurate reading. Then, raise the hood, position the prop rod, and measure the oil with the dipstick which is on the left side of 4-cylinder and on the right side of 6-cylinder engines. Add oil through the filler pipe on the right side of 4–134 engines, through the valve cover filler hole on 6–225 engines and through the filler pipe on the left side of the 6–226 and 6–230 engines.
If the oil is below the ADD mark, add a 1 qt. (0.947L) of oil, then recheck the level. If the level is still not reading full, add only 1⁄2 qt. (0.473L) at a time, until the dipstick reads FULL. Do not overfill the engine. When you check the oil, make sure that you allow sufficient time for all of the oil to drain back into the crankcase after stopping the engine. A minute or so should be enough time.
OIL AND FILTER CHANGE
Fig. 1: For Jeep models equipped with a spin-on type oil filter, follow this general procedure to change the oil and filter
Fig. 2: The inline 6-cylinder engines (6–226 and 6–230) utilize a spin-on type oil filter as shown — always apply a film of clean engine oil to the filter gasket prior to installation
Fig. 3: Remove the oil pan drain plug . . .
Fig. 4: . . . and drain the oil into a suitably-sized catch pan
Fig. 5: While the oil pan drains, remove the oil filter cover hold-down bolt . . .
Fig. 6: . . . and remove the oil filter cover
Fig. 7: Remove the filter element from the canister for replacement or cleaning
Fig. 8: Install the filter and cover, then remove the oil filler cap
Fig. 9: Install the oil pan drain plug, then fill the engine with clean engine oil
Before draining the oil, make sure that the engine is at operating temperature. Hot oil will hold more impurities in suspension and will flow better, removing more oil and dirt.
Drain the oil into a suitable receptacle. After the drain plug is loosened, unscrew the plug with your fingers, using a rag to shield your fingers from the heat. Push in on the plug as you unscrew it so you can feel when all of the screw threads are out of the hole. You can then remove the plug quickly with the minimum amount of oil running down your arm. You will also have the plug in your hand and not in the bottom of a pan of hot oil.
Change the oil filter every time you change the oil. The engine should be at operating temperature. On the older L4–134 and F4–134 and all 6–226 engines, the oil filter is located on the right side forward part of the top of the engine. To change the element, remove the bolt, remove the lid, and remove and discard the element. Clean out the cup with a clean, dry cloth and flushing oil or clean, light viscosity engine oil. Clean the lid in the same manner and remove and discard the old gasket. Replace it with a new one. Do not use a solvent that could get into the oil and dilute it. Place the new filter element in the cup. Place the lid on the cup and the bolt down through the center. Tighten the bolt to 10–15 ft. lbs. (14–20 Nm). Start the engine and look for leaks. If a leak does develop, turn the engine OFF and remove the oil filter lid. Inspect the gasket to see if it is seated properly. Adjust the gasket if needed. Install the lid, start the engine, and check for leaks. If the leak persists, tighten the bolt further.
On the newer F4–134, 6–225, and 6–230 engines, the oil filter is the spin-on type. On the F4–134 engines, the filter is in the same place as the former cartridge type filter. On the V6 engine, the filter is on the right side of the engine just below the alternator. On the 6–230, it is at the lower left front of the block.
To replace the filter, you will need an oil filter wrench. Loosen the filter with the filter wrench. With a rag wrapped around the filter, unscrew the filter from the oil pump housing. Be careful of hot oil that might run down the side of the filter, especially on the inline 6-cylinder engines. On the F4–134 engines, the filter is mounted with the open side facing downward so you won’t have to worry about oil running down on your hand. Make sure that you have a pan under the filter before you start to remove it from the engine so you won’t make a mess and, if some of the hot oil does happen to get on you, you will have a place to dump the filter in a hurry. Wipe the base of the mounting plate with a clean, dry cloth. When you install the new filter, smear a small amount of oil on the gasket with your finger, just enough to coat the entire surface where it comes in contact with the mounting plate. When you tighten the filter, turn it only a 1⁄4 turn after it comes in contact with the mounting plate.
Manual Transmission
FLUID LEVEL CHECK
Fig. 1: Most manual transmissions are equipped with both a fill plug (arrow) and a drain plug (bottom plug)
Fig. 2: If your particular transmission does not have a drain plug, remove the lowest tailshaft bolt to drain the fluid
The level of lubricant in the transmission should be maintained at the filler hole on all manual transmissions. This hole is on the right side. When you check the level in the transmission, make sure that the vehicle is level so that you get a true reading. When you remove the filler plug, lubricant should run out of the hole. Replace the plug quickly for a minimum loss of lubricant. If lubricant does not run out of the hole when the plug is removed, lubricant should be added until it does. Replace the plug as soon as the lubricant reaches the level of the hole.
FLUID CHANGE
Remove the drain plug which is at the bottom of the transmission or else on the side near the bottom. Allow all the lubricant to run out before reinstalling the plug. Refill the case with the correct viscosity oil. All manual transmissions, except the T4 and T5, use SAE 80W-90 gear oil. The T4 and T5 manual transmissions use Dexron® II Automatic Transmission Fluid (ATF).
Automatic Transmission
FLUID LEVEL CHECK
The fluid level in automatic transmissions is checked with a dipstick in the filler pipe at the right rear of the engine. The fluid level should be maintained between the ADD and FULL marks on the end of the dipstick with the automatic transmission fluid at normal operating temperature. To raise the level from the ADD mark to the FULL mark, requires the addition of 1 pt. (0.473L) of fluid. The fluid level with the fluid at room temperature (75°F) should be approximately 1⁄4 in. (6mm) below the ADD mark.
NOTE: In checking the Automatic Transmission Fluid (ATF), insert the dipstick in the filler tube with the markings toward the center of the vehicle. Also, remember that the FULL mark on the dipstick is calibrated for normal operating temperature. This temperature is obtained only after at least 15 miles (24 km) of expressway driving or the equivalent of city driving.
With the transmission in Park, the engine running at idle speed, the foot brake applied and the vehicle resting on level ground, move the transmission gear selector through each of the gear positions, including Reverse, allowing time for the transmission to engage. Return the shift selector to the Park position and apply the parking brake. Do NOT turn the engine OFF, but leave it running at idle speed.
Clean all dirt from around the transmission dipstick cap and the end of the filler tube.
Pull the dipstick out of the tube, wipe it off with a clean cloth, and push it back into the tube all the way, making sure that it seats completely.
Pull the dipstick out of the tube again and read the level of the fluid on the stick. The level should be between the ADD and FULL marks. If fluid must be added, add enough fluid through the tube to raise the level to between the ADD and FULL marks. Do not overfill the transmission because this will cause foaming and loss of fluid through the vent.
NOTE: Use only Dexron® or Dexron® II transmission fluid.
If, when the ATF level is checked, the fluid is noticed to be discolored from a clear red to brown, has a burned smell, or contains water, it should be changed immediately.
Drive the vehicle for at least 20 minutes at expressway speeds or the equivalent to raise the temperature of the fluid to its normal operating range.
Drain the ATF into an appropriate container before it has cooled. The fluid is drained by loosening the transmission pan and allowing the fluid to run out around the edges. It is best to loosen only one corner of the pan and allow most of the fluid to drain out.
Remove the remaining pan screws, and remove the pan and pan gasket.
Remove the strainer and discard it.
Remove the O-ring seal from the pick-up pipe and discard it.
Install a new O-ring seal on the pick-up pipe and install the new strainer and pipe assembly.
Thoroughly clean the bottom pan and position a new gasket on the pan mating surface.
Install the pan and tighten the attaching screws to 121–158 inch lbs. (14–18 Nm).
Pour about 5 qts. (4.74L) of Dexron® or Dexron® II ATF down the dipstick tube. Make sure that the funnel, container, hose or any other item used to assist in filling the transmission is clean.
Start the engine with the transmission in Park. Do NOT race it. Allow the engine to idle for a few minutes.
After the engine has been running for a few minutes, move the selector lever through all of the gears.
With the selector lever in Park, check the transmission fluid level and adjust as necessary. Remember the ATF must be warm when at the Full mark.
Transfer Case
FLUID LEVEL CHECK
The Spicer 18 was the only transfer case available in 4WD models from 1945–70. The transfer case should be checked in the same manner as the manual transmission. The level should be up to the filler hole. Use the same viscosity oil as in the transmission. The filler hole is on the right side. Check the oil level at the top hole. The bottom plug is the drain plug.
NOTE: Some models may be equipped with a two piece fill plug (a small threaded plug inside a larger one). If your transfer case is so equipped, the fluid level is checked at the bottom of the smaller plug. To remove the smaller plug, hold the larger one firmly with a wrench while removing the smaller plug.
DRAIN & REFILL
All manual transfer cases are to be serviced at the same time and in the same manner as the manual transmissions. The transfer case has its own drain plug which should be opened. Do not rely on the transmission drain plug to completely drain the transfer case, even if they are interconnected. Once the transfer case has been drained, replace the drain plug, remove the fill plug and fill the transfer case. The Spicer 18 uses SAE 80W-90 gear oil. Replace the fill plug.
Drive Axles
FLUID LEVEL CHECK
Fig. 1: The fill plugs on both the front and rear drive axles are located in the middle of the differential covers
Fig. 2: Before checking and/or draining the differential fluid, brush away dirt from both the drain and fill plugs
The standard front and rear axle differentials use SAE 80W/90 gear oil. Either is acceptable for use in the differential housing. Powr-Lok® differentials use only Jeep Powr-Lok® Lubricant or its equivalent. In Trac-Lok® axles, use any limited slip gear oil meeting SAE 75W/90, 80W/90 or 85W/90 specifications. Check the level of the oil in the differential housing every 5,000 miles (8,000 km) under normal driving conditions and every 3,000 miles (4,800 km) if the vehicle is used in severe driving conditions. The level should be up to the filler hole. When you remove the filler plug, the oil should start to run out. If it does not, replenish the supply until it does.
The lubricant should be changed every 30,000 miles (48,000 km). If running in deep water, change the lubricant daily.
DRAIN & REFILL
Fig. 1: To drain the differential fluid, first loosen (but do not remove) the fill plug
Fig. 2: Remove the drain plug . . .
Fig. 3: . . . and allow the differential oil to drain into a catch pan
Fig. 4: Remove the fill plug in order to fill the differential case
Fig. 5: If the differential cover gasket leaks and must be replaced, remove the retaining bolts
Fig. 6: Gently pry the cover away from the case and allow residual oil to drain
Fig. 7: Remove the case cover from the differential and . . .
Fig. 8: . . . cover the differential with a shop rag, then remove any old gasket material
Use a wire brush or rag to clean the area around the drain and fill plugs.
Loosen (but do not remove) the fill plug, to make sure that it can be turned easily. If necessary, spray penetrating lubricant.
Position a suitable catch pan, then loosen and remove the drain plug. Allow the lubricant to empty out.
If the differential cover gasket leaks (or differential service is required), perform Steps 4a–4d:
Remove the axle differential housing cover and allow the remaining lubricant to drain into the pan.
Cover the differential with a clean rag, and remove any old gasket material. Remove the rag.
Install the differential housing cover with a new gasket.
Tighten the cover attaching bolts to 15–25 ft. lbs. (20–34 Nm).
Install and tighten the drain plug.
Remove the fill plug and add new lubricant to the fill hole level.
Install and tighten the fill plug.
NOTE: Trac-Lok® (limited-slip) differentials may be cleaned only by disassembling the unit and wiping with clean, lint-free rags.
LEVEL CHECK
Fig. 1: An antifreeze tester can be used to determine the freezing and boiling level of the coolant
The coolant level should be maintained about 1⁄2 in. (13mm) below the filler neck of the radiator with 4L–134, 4F–134, 6–226 and 6–230 engines.
On the 6–225 engine, the coolant level should be maintained 1 1⁄2 –2 in. (38–51mm) below the bottom of the filler cap when the engine is cold. Since operating temperatures reach as high as 205°F (96°C), coolant could be forced out of the radiator if it is filled too high. The radiator coolant level should be checked regularly, such as every time you refuel the vehicle. Never open the radiator cap of an engine that hasn’t had sufficient time to cool or the pressure can blow off the cap and send out a spray of scalding water.
On systems with a coolant recovery tank, maintain the coolant level at the level marks on the recovery bottle.
For best protection against freezing and overheating, maintain an approximate 50% water and 50% ethylene glycol (or other suitable) antifreeze mixture in the cooling system. Do not mix different brands of antifreeze to avoid possible chemical damage to the cooling system.
Avoid using water that is known to have a high alkaline content or is very hard, except in emergency situations. Drain and flush the cooling system as soon as possible after using such water.
CAUTION
Cover the radiator cap with a thick cloth before removing it from a radiator in a vehicle that is hot. Turn the cap counterclockwise slowly until pressure can be heard escaping. Allow all pressure to escape from the radiator before completely removing the radiator cap. It is best to allow the engine to cool if possible, before removing the radiator cap.
NOTE: Never add cold water to an overheated engine while the engine is not running.
After filling the radiator, run the engine until it reaches normal operating temperature, to make sure that the thermostat has opened and all the air is bled from the system.
DRAINING, FLUSHING AND REFILLING
Fig. 1: The cooling system should be pressure tested once a year
Fig. 2: Whenever servicing your cooling system, take a few moments to clear the radiator fins of debris, to allow your system to provide maximum engine cooling
Fig. 3: Inspect the radiator cap rubber gasket and metal seal for any deterioration at least once a year
CAUTION
When draining coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.
To drain the cooling system, allow the engine to cool down BEFORE ATTEMPTING TO REMOVE THE RADIATOR CAP. Then turn the cap until it hisses. Wait until all pressure is off the cap before removing it completely.
CAUTION
To avoid burns and scalding, always handle a warm radiator cap with a heavy rag.
At the dash, set the heater TEMP control lever to the fully HOT position.
With the radiator cap removed, drain the radiator by loosening the petcock at the bottom of the radiator. Locate any drain plugs in the block and remove them. Flush the radiator with water until the fluid runs clear.
Close the petcock and replace the plug(s), then refill the system with a 50/50 mix of ethylene glycol or other suitable antifreeze. Fill the system to 3⁄4 –1 1⁄4 in. (19.05–31.75mm) from the bottom of the filler neck. Reinstall the radiator cap.
NOTE: If equipped with a fluid reservoir tank, fill it up to the MAX level.
Operate the engine at 2,000 rpm for a few minutes and check the system for signs of leaks.
Radiator Cap Inspection
Allow the engine to cool sufficiently before attempting to remove the radiator cap. Use a rag to cover the cap, then remove by pressing down and turning counterclockwise to the first stop. If any hissing is noted (indicating the release of pressure), wait until the hissing stops completely, then press down again and turn counterclockwise until the cap can be removed.
CAUTION
DO NOT attempt to remove the radiator cap while the engine is hot. Severe personal injury from steam burns can result.
Check the condition of the radiator cap gasket and seal inside of the cap. The radiator cap is designed to seal the cooling system under normal operating conditions which allows the build up of a certain amount of pressure (this pressure rating is stamped or printed on the cap). The pressure in the system raises the boiling point of the coolant to help prevent overheating. If the radiator cap does not seal, the boiling point of the coolant is lowered and overheating will occur. If the cap must be replaced, purchase the new cap according to the pressure rating which is specified for your vehicle.
Prior to installing the radiator cap, inspect and clean the filler neck. If you are reusing the old cap, clean it thoroughly with clear water. After turning the cap on, make sure the arrows align with the overflow hose.
Brake and Clutch Master Cylinders
The master cylinder is located under the floor. To check the level of the brake fluid remove the floor plate. Clean the area of all dirt so that, when you remove the cover, no dirt will fall in and contaminate the brake fluid. Dirt in the hydraulic system could score the inside of the master cylinder or wheel cylinders and cause leakage or brake failure. Unscrew the lid of the master cylinder with a wrench. The fluid level should be within 1⁄2 in. (13mm) from the top of the reservoir chamber. Use only heavy duty brake fluid and keep it away from any other fluids or vapors that could contaminate it.
If the master cylinder is less than half full, there is probably a leak somewhere in the hydraulic system. Investigate the problem before driving the vehicle.
Power Steering Pump
FLUID LEVEL CHECK
The level of the fluid should be at the correct point on the dipstick attached to the inside of the lid of the power steering pump. Replenish the supply with DEXRON® II Automatic Transmission Fluid (ATF).
Manual Steering Gear
FLUID LEVEL CHECK
There is a fill plug on top of the steering gear box. The level should be maintained at the bottom of the fill plug hole. The correct lubricant is SAE 80W/90 gear oil.
Steering Knuckle
FLUID LEVEL CHECK
The axle shaft universal joints are located in the steering knuckle and are bathed in oil as they turn. To check the fluid level in the steering knuckle, remove the filler plug from the inside of the knuckle. The fluid should be at the level of the hole. If it is not, replenish the supply. Examine the knuckle for leaks if the level is abnormally low. A leak should be readily visible.
Chassis Greasing
Chassis greasing should be performed every 6 months or 7,500 miles (12,000 km) for Jeeps used in normal or light service. More frequent greasing is recommended for Jeeps in heavy or severe usage: every 3 months or 3,000 miles (4,800 km). Greasing can be performed with a commercial pressurized grease gun or at home by using a hand-operated grease gun. Wipe the grease fittings clean before greasing in order to prevent the possibility of forcing any dirt into the component.
Water resistant EP chassis lubricant (grease) should be used for all chassis grease points.
