Pre and post off road checks and maintenance

[Rhoda]

Hi all. As a new Jeep owner and off road adventurer Im still getting to know my JKU 2.8CRD. 
Can folks please tell me what checks, maintenance and lubrication they do before and after off roading?

Thank you. 

Edited March 1 by Rhoda

[MGomes]

From a "non-mechanical mind-set" - there are a few things that I always keep an eye for:

 

1. Car is serviced as recommended;

2. Visual checks on tires, and just a look (before and after off-roading)

3. Ensure all fluids are topped up (before heading out with engine cold)

4. Ensure radiator is clear of debris afterwards (essential if on the Salisbury Plain)

5. Have the car cleaned as soon as possible (again - essential on the Salisbury Plain - even if just for visual checks)

6. Check air filter (this is rather easy - "even I can do it"  )

7. Clean Engine bay / wash the back of radiators with clean fresh running water (no pressure washer)

 

I am sure there are plenty more things that need to be done - again as a "non mechanic" I am restricted to my own knowledge and what I can do - I do a lot of mileage with Hank (for a Wrangler) - so the car is serviced usually twice a year, so that helps as well

[jeepstertim]

It slightly depends how adventurous you have been, but everything above is sound advice.

 

If you have been in deep water it may be worth checking for oil contamination in the diffs, noting you have a snorkel, have the axle breathers been raised as well?

[V]

After off road driving my Jeep will often have a lot of dirt underneath and on the running gear. Depending on the weather it usually dries out quickly and reveals any oil leaks in the areas that are dirty. The patches that look oily wet while the rest is dry are the areas to investigate further after jet washing.

 

Jet wash everything underneath and spend more time cleaning from behind the wheel than on the pretty side to make sure as much dirt and foliage is washed away from the brakes and hubs. If your Jeep has rear drum brakes, wash around the back plate so water goes inside the drum and watch for dirt leaving at the bottom. When it runs consistently clear you can be sure you have got rid of most of it.

 

I think most Jeeps with rear disc brakes and without electric handbrake will have a little drum brake inside the disc rotor. Some clays can harden quickly and foul the drum brake mechanism very quickly. This can cause a wheel to be hot to touch, hot enough to blister your skin. I put some spittle on my finger and touch a suspected hot wheel for a split second to confirm a problem. If it is bad you can often smell the heat and hear it clicking under cooling contraction. If the wheel is hot, wait for the wheel to cool down to ambient temperature before jet washing. Sometimes this is enough to fix the problem. Otherwise, removing the wheel and dismantling the brakes for cleaning is necessary. If it is not done, the brake shoes wear out. The excess heat can also cause accelerated wear on the wheel bearing and contribute to other rear brake faults that could affect ABS and ESP.

 

I crawl under my Jeep and inspect everything for damage. Skid plates, cross members, exhaust mounts, exhaust joints/clamps, propshafts, universal joints, oil pans, steering, springs, shock absorbers, anti-roll bar, recovery points, brake pipes, fuel pipes, hoses and wiring. There is a lot of stuff underneath that can get snagged or crushed off road.

 

After cleaning, I grease every grease fitting I can get easy access to. Those that are difficult to get to are done on a six month service interval when I can remove parts to get to them. When I use up my current stock of greasable universal joints I will be switching to non-greasable u-joints. I am sticking with greasable ball joints.

[Rhoda]

Fast learning about all sorts of gremlins on my Jeep - the main ones appear to relate to dodgy electrics and need for decent regular lubrication. 
I’ve filled every grease nipple I can find and am taking the squeaky rear prop off this weekend to put back non- greasable U joints - but I keep finding more places to grease that I didn’t know existed! Does anyone have a list of grease points - nipples, needle points, U joints and smear on with the finger type places?

[Rhoda]

32 minutes ago, jeepstertim said:

It slightly depends how adventurous you have been, but everything above is sound advice.

 

If you have been in deep water it may be worth checking for oil contamination in the diffs, noting you have a snorkel, have the axle breathers been raised as well?

Good call. Changing the oil in the diffs and extending the breathers a bit more is on my list of jobs. Also remembering to put the bungs back in the floor as I didn’t on the time below!

[V]

Diff oil will look like chocolate milkshake when contaminated with dirty water. If left standing still for a number of days the oil will separate from the water and float on top of it. You can take an oil sample through the filler hole using a large medical syringe and a length of small bore transparent hose poked in the hole down to the bottom of the diff. If water is in the sample, or the oil is brown, drain the oil by removing the diff cover and clean the inside of the diff as best as you can with brake cleaner spray and paper towels. Reseal the diff cover with gear oil proof silicon and follow the instructions including the curing times before refilling and driving. Sometimes, you can get away cutting corners on silicon application but you have to be lucky to avoid leaks, water ingestion or both.

 

Black gear oil is OK to leave in the diff if still within change interval. If you have just driven the Jeep and taken a sample of warm oil it may be light brown in colour due to aeration. Take the sample when the diff is cold to allow the air to separate from the oil. The axle breather will allow air to enter the housing so condensation inside the housing is normal. Gear oil is able to withstand some emulsification with condensation which is why a warm sample will be brown and a cold sample should be black or a shade between new oil and black. Contamination with a larger quantity of dirty water will make the oil brown when warm and when cold. Recognising the difference between good used gear oil and contaminated gear oil is something you learn by doing. If in doubt, just change it.

 

You can buy gear oil in 10L, 20L and 25L drums. It is substantially cheaper than buying it in 1L or 5L packs but as with most things it has a use by date. I have two off road Jeeps so I use at least 10L every year sometimes 20L. Your front axle may require a different lubricant to the rear axle.

[digger]

Only comment I would make is  when 'V; said '' I crawl under my Jeep''.....  for some things that is what I do but when I want to move around a lot, such as inspecting , I use a  'creeper'.  This is because I am no longer as  fit as I once was and it makes life easier! This may apply to some of you!  The one I use now was quite cheap, I think about £30! It works very well as long as the surface isn't too rough and I can wizz about shifting position!  Its reasonably comfortable but didn't have any padding on the side rails. Being fairly big build I found that uncomfortable, so I fitted the rails with thick pipe insulation! No prob now!

Mine is similar to the one below. google!  The 'pillow bit' is worth having!

 

 

Folding Headrest Professional Mechanics Car Creeper (sgs-engineering.com)

 

Edited March 1 by digger

[Spike64]

Hi, a quick question about diff oil, I have a 2020 JL Rubicon the hand book states : Mopar Gear and Axle Lubricant SAE 75/W85 API GL-5. Do I need a specific Mopar product or will any GL-5 gear oil be OK ?

Many thanks

Ian

 

 

[V]

I don't know if FCA put unique dyes in their lubricants, but VW/Audi use Castrol lubricants with special dyes in them that are not available in Castrol's retail product. I assume they do this to check for non-franchised maintenance. If your Jeep is in warranty, using Mopar lubricants is one less thing to worry about if making a claim relevant to a lubrication problem. Out of warranty you can use any SAE 75w-85 API GL-5 gear oil.

[Spike64]

I am still very much making use of my warranty ! so Mopar for me. 

Thanks for the info 

[V]

If you get on with the service manager, ask them what they use. In the old days, before FCA, dealers didn't always use Mopar lubricants, they bought oil in 210L drums of the correct API spec for each application. I've had new Chryslers that I have run in on the factory engine oil, run one more interval on semi-synth and then after that Mobil-1 that I supplied. Invoice just said oil change using customer supplied Mobil-1 5w-40 fully synthetic for every service over the next 6 years. I never had any problems with warranty.

[Spike64]

Thanks, I will give that a try, i'm due back at the garage in a couple of weeks. I see them more than the in-laws !

 

[digger]

3 hours ago, Spike64 said:

Hi, a quick question about diff oil, I have a 2020 JL Rubicon the hand book states : Mopar Gear and Axle Lubricant SAE 75/W85 API GL-5. Do I need a specific Mopar product or will any GL-5 gear oil be OK ?

Many thanks

Ian

 

 

You do need to be careful, there are still rogues about who use whatever from a big drum!!

[Rhoda]

5 hours ago, V said:

Diff oil will look like chocolate milkshake when contaminated with dirty water. If left standing still for a number of days the oil will separate from the water and float on top of it. You can take an oil sample through the filler hole using a large medical syringe and a length of small bore transparent hose poked in the hole down to the bottom of the diff. If water is in the sample, or the oil is brown, drain the oil by removing the diff cover and clean the inside of the diff as best as you can with brake cleaner spray and paper towels. Reseal the diff cover with gear oil proof silicon and follow the instructions including the curing times before refilling and driving. Sometimes, you can get away cutting corners on silicon application but you have to be lucky to avoid leaks, water ingestion or both.

 

Black gear oil is OK to leave in the diff if still within change interval. If you have just driven the Jeep and taken a sample of warm oil it may be light brown in colour due to aeration. Take the sample when the diff is cold to allow the air to separate from the oil. The axle breather will allow air to enter the housing so condensation inside the housing is normal. Gear oil is able to withstand some emulsification with condensation which is why a warm sample will be brown and a cold sample should be black or a shade between new oil and black. Contamination with a larger quantity of dirty water will make the oil brown when warm and when cold. Recognising the difference between good used gear oil and contaminated gear oil is something you learn by doing. If in doubt, just change it.

 

You can buy gear oil in 10L, 20L and 25L drums. It is substantially cheaper than buying it in 1L or 5L packs but as with most things it has a use by date. I have two off road Jeeps so I use at least 10L every year sometimes 20L. Your front axle may require a different lubricant to the rear axle.

V helpful - thanks. Learned about water in the diff oil  (and engine oil, and ATF) after drowning my Landrover on Salisbury Plain - ooops! The oil in the Jeep diffs looks OK on dipping it but is a few years old now (although only a couple of thousand miles) so I’d be happier once it’s changed. 

[JimC]

Keep hold of your old air filter.
When you go off road, switch out your good air filter and swap it with your old dirty one.

[jeepstertim]

18 hours ago, Spike64 said:

Hi, a quick question about diff oil, I have a 2020 JL Rubicon the hand book states : Mopar Gear and Axle Lubricant SAE 75/W85 API GL-5. Do I need a specific Mopar product or will any GL-5 gear oil be OK ?

Many thanks

Ian

 

 

 

17 hours ago, V said:

I don't know if FCA put unique dyes in their lubricants, but VW/Audi use Castrol lubricants with special dyes in them that are not available in Castrol's retail product. I assume they do this to check for non-franchised maintenance. If your Jeep is in warranty, using Mopar lubricants is one less thing to worry about if making a claim relevant to a lubrication problem. Out of warranty you can use any SAE 75w-85 API GL-5 gear oil.

 

Some of the Jeep diffs also need a special lubricant to go in as well.