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Fluid Changes ??

LawrenceR

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I have a question for those of you in the know....

I just took delivery of my new 2020 Willys. I talked with the Service Manager, generally asking him when should the Rear Diff fluid be changed, etc, etc. He wasn't very specific.

Upon reading through my owners manual, it only states that the Engine Oil (crankcase) should be changed when the information system tells me to, nothing to the effect of "...every 3000 miles or when the system tells me to..."

I've read on this site that some owners are changing their Rear Diff fluid more often than I would expect and from what I understand, the information system doesn't have a way to warn or monitor this.

Same goes for the Transfer Case...

Does anyone in the know have any suggestions as to when one should change the fluids and with which product for the following:
1. Crank case
2. Transfer case
3. Rear Diff.

Any help will be much appreciated.
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mgroeger

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I have a question for those of you in the know....

I just took delivery of my new 2020 Willys. I talked with the Service Manager, generally asking him when should the Rear Diff fluid be changed, etc, etc. He wasn't very specific.

Upon reading through my owners manual, it only states that the Engine Oil (crankcase) should be changed when the information system tells me to, nothing to the effect of "...every 3000 miles or when the system tells me to..."

I've read on this site that some owners are changing their Rear Diff fluid more often than I would expect and from what I understand, the information system doesn't have a way to warn or monitor this.

Same goes for the Transfer Case...

Does anyone in the know have any suggestions as to when one should change the fluids and with which product for the following:
1. Crank case
2. Transfer case
3. Rear Diff.

Any help will be much appreciated.
A lot depends on how you use the Jeep. We off road and take it across country so I'm a little OCD on the changes. Here's my 2 cents... feel free to give me change.

Oil - I use Pennzoil full platinum 0w-20 in winter 5w-20 in summer every 4k miles. I don't care what the computer thinks or tells me. It's $24 for a jug and $9 for a Mopar filter at Wally World and takes 15 mins.
T-Case - At least once a year, more if we are wheeling it hard. Again... it's 2 qts at $6 to $9 each... cheap insurance.
Diffs - Twice a year maybe more like doing it before a long road trip. You can do the front one every other time you do the rear. Also a good idea once a year at least to take the diff cover off and get a can of brake cleaner and spray it out for a good inspection. Don't go bonkers with spraying the cleaner in there. Just get it on the ring and bottom of the housing good. Don't go spraying it right at the bearings. Again good quality qt of Lucas full synthetic or Valvoline is like $14 and it takes around 1.5 qts per axle for the D44s.

Some may say this is overkill and that's fine but for peace of mine and LONG term ownership this is what I do.
No here's the kicker... I am coming up on 60k miles and need to do my tranny so I need to do a little research on that. Don't want to pay the dealer.
 
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LawrenceR

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Thank you and I'm in agreement "fluid changes are the cheapest insurance". I also don't care what the computer is telling me. My dad built and blueprinted engines, "...every 3000 miles" do an oil change...
 

Rhinebeck01

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Thank you and I'm in agreement "fluid changes are the cheapest insurance". I also don't care what the computer is telling me. My dad built and blueprinted engines, "...every 3000 miles" do an oil change...
Doing routine oil changes on a JL 3.6, every 3,000 miles, is nonsensical at best.

The JL does not have an engine manufactured in 1968 , nor is it a vehicle using the caliber of fluids / oil filters used way back then.

With today's fluids, filters and the way engines are manufactured/assembled it is a whole different deal lets say...
 

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LawrenceR

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I see in the a
Doing routine oil changes on a JL 3.6, every 3,000 miles, is nonsensical at best.

The JL does not have an engine manufactured in 1968 , nor is it a vehicle using the caliber of fluids / oil filters used way back then.

With today's fluids, filters and the way engines are manufactured/assembled it is a whole different deal lets say...
I agree, everyone is entitled to their own opinion, but let's take a moment to look at things.

Let's assume, I change my engine oil and filter every 3000 miles, assuming my engine will last for 100,000 miles, this would mean I would perform 33.3 oil changes over the life of the engine.

I already purchased the oil (0-20) and filter for my 2020 Willys at a cost of just under $30.00. I would spend over the length of 100,000 miles just under $1,000.00 (33 changes at a cost of $30.00)

Now, let's not get into the discussion of how prices should naturally go up over time, there is no true way to predict what oil and filter will cost later on.

Now, if I didn't change my oil as frequently ( I noticed you didn't mention how often you felt changing engine oil was considered " sensical " - but let's say you feel changing engine oil at 5,000 miles is..

While you are changing your oil/filter only 20 times and I am changing mine 33 times, the difference is 13 oil/filter changes at a cost of $30.00, meaning you are saving $1,390.00 - over the entire life of the engine.

What would it cost to either rebuild or replace the engine ? Roughly $5,000.00

Who is really coming out ahead ?
 

mwilk012

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I see in the a


I agree, everyone is entitled to their own opinion, but let's take a moment to look at things.

Let's assume, I change my engine oil and filter every 3000 miles, assuming my engine will last for 100,000 miles, this would mean I would perform 33.3 oil changes over the life of the engine.

I already purchased the oil (0-20) and filter for my 2020 Willys at a cost of just under $30.00. I would spend over the length of 100,000 miles just under $1,000.00 (33 changes at a cost of $30.00)

Now, let's not get into the discussion of how prices should naturally go up over time, there is no true way to predict what oil and filter will cost later on.

Now, if I didn't change my oil as frequently ( I noticed you didn't mention how often you felt changing engine oil was considered " sensical " - but let's say you feel changing engine oil at 5,000 miles is..

While you are changing your oil/filter only 20 times and I am changing mine 33 times, the difference is 13 oil/filter changes at a cost of $30.00, meaning you are saving $1,390.00 - over the entire life of the engine.

What would it cost to either rebuild or replace the engine ? Roughly $5,000.00

Who is really coming out ahead ?
Well given that the realistic change interval is closer to 10,000 miles than 5,000 and the only way you are going to need an engine is if you have an oil leak or consumption that goes undetected in that time frame, you are definitely coming out behind by several thousand dollars over the life of the vehicle. However, this is America, you do you boo.

Also, on topic: don't believe the sources that say the ZF 8speed transmission has a "lifetime fill". It needs to be flushed at 100,000 mile intervals, or more often if economically feasible. The fluid is hella expensive.
 

KIVO

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Also, on topic: don't believe the sources that say the ZF 8speed transmission has a "lifetime fill". It needs to be flushed at 100,000 mile intervals, or more often if economically feasible. The fluid is hella expensive.
The ZF 8HP service manual says:
Jeep Wrangler JL Fluid Changes ?? ZF.JPG

It is not just the fluid, you'll need to replace the tranny pan, which holds the filter (filter is part of).
 

mwilk012

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The ZF 8HP service manual says:
Jeep Wrangler JL Fluid Changes ?? ZF.JPG

It is not just the fluid, you'll need to replace the tranny pan, which holds the filter (filter is part of).
Good point, thanks!
 

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The ZF 8HP service manual says:
Jeep Wrangler JL Fluid Changes ?? ZF.JPG

It is not just the fluid, you'll need to replace the tranny pan, which holds the filter (filter is part of).
Thanks for these numbers this is exactly what I was wanting to know. At 60k miles I am considering myself overdue based on that info. Not dangerously overdue but I need to change it. I did know that the filter was in the pan. The next question is what fluid does it take? I assumed it took the ATF+4 but sounds like it doesn't.
 

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mwilk012

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Thanks for these numbers this is exactly what I was wanting to know. At 60k miles I am considering myself overdue based on that info. Not dangerously overdue but I need to change it. I did know that the filter was in the pan. The next question is what fluid does it take? I assumed it took the ATF+4 but sounds like it doesn't.
NOOOOOOO. It takes its own fluid, Mopar 8 speed transmission fluid. It's $24 or more a quart.
 

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I am not sure what axle is in your Willys, but based upon what the 5K and 10K UOAs showed in the D44 electronic axle in my Rubicon, I would change it at 5K or less. If it is the Limited Slip axle, you will want to at least check it again at 10K, if not outright change it. I would also seriously consider upping the viscosity to 75W-140 to provide more protection.

In a couple of thousand miles, I will be testing mine again to see how it is doing and decide if I will change it. One thing is certain, with the reduction of oil capacity from the JK to the JL series and with the issues they have been having, these axles are not made for long oil change intervals.
 

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You guys - you know that if this is not a Jeep forum with the ongoing craziness that is going on - one would think that you are talking about changing sex you know - like "fluids" people?? :giggle:

(haha I am so gonna get banned for saying this)
Yeah, I constantly refer to the transmission as tranny since that's what we grew up calling them. I'm not changing...
 

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I am not sure what axle is in your Willys, but based upon what the 5K and 10K UOAs showed in the D44 electronic axle in my Rubicon, I would change it at 5K or less. If it is the Limited Slip axle, you will want to at least check it again at 10K, if not outright change it. I would also seriously consider upping the viscosity to 75W-140 to provide more protection.

In a couple of thousand miles, I will be testing mine again to see how it is doing and decide if I will change it. One thing is certain, with the reduction of oil capacity from the JK to the JL series and with the issues they have been having, these axles are not made for long oil change intervals.
I second upping the fluid if you do a lot of road trips and/or solid off roading. The manual doesn't talk about that, they only talk about towing. The point being anything more than mall crawling, i.e. these weirdos who put 2k miles a year on their Jeep, I'd bump the viscosity up.
 

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I see in the a


I agree, everyone is entitled to their own opinion, but let's take a moment to look at things.

Let's assume, I change my engine oil and filter every 3000 miles, assuming my engine will last for 100,000 miles, this would mean I would perform 33.3 oil changes over the life of the engine.

I already purchased the oil (0-20) and filter for my 2020 Willys at a cost of just under $30.00. I would spend over the length of 100,000 miles just under $1,000.00 (33 changes at a cost of $30.00)

Now, let's not get into the discussion of how prices should naturally go up over time, there is no true way to predict what oil and filter will cost later on.

Now, if I didn't change my oil as frequently ( I noticed you didn't mention how often you felt changing engine oil was considered " sensical " - but let's say you feel changing engine oil at 5,000 miles is..

While you are changing your oil/filter only 20 times and I am changing mine 33 times, the difference is 13 oil/filter changes at a cost of $30.00, meaning you are saving $1,390.00 - over the entire life of the engine.

What would it cost to either rebuild or replace the engine ? Roughly $5,000.00

Who is really coming out ahead ?
Not to rain on your parade and not trying to be a jerk or know-it-all and you are certainly entitled to do what works for you, but:

1. Move your OCI to 5K and save a bit of money, there is ZERO statistical data to show that you are extending the life of your engine between a 3K and a 5K oil change interval.

2. Throw the "prices will go up" idea out of the window. I have paid less for synthetic oil in 2019 than I did for conventional in 2009. There are **always** rebates and specials that reduce the cost significantly or make it free.

3. Unless you seriously abuse the engine, 100K should be a good starting point and not the end of the engine's life. There was a First Generation 3.6L Pentastar that was recently dissected at 625,000 miles and the major mechanical components were still in very serviceable condition.

4. Based upon your example above, the challenge would be to show what was gained by spending the extra $1,390 versus lost by saving it.

5. Oils and oil filters have DRAMATICALLY improved in the past 5 years and if you are "dead set" on running a 3K OCI, then purchase the cheapest specified oil and filter that you can find--nothing will be gained in the slightest by using anything else.
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