My Next Project (Axle Temperature Gauges)

[CarbonSteel]

I have a set of ISS Pro temperature gauges (made specifically for the front and rear axles) that I will be installing soon. In order to do that I needed to weld in a 1/8” NPT boss into the tops of the covers (I am using OEM covers as rock crawling is not in my future). After studying several videos of oil splash patterns inside axles in operation, I selected a location near the center of the ring gear as it will push the vast majority of oil to the top and slightly left of the centerline and will keep the temperature sensor well covered in oil.

Since the majority of axle wear occurs at 15K miles or less, I plan to dump the oil at 5K (and clean out the housing while switching covers) and I will probably dump it again at 15K and call if good until 65K. Amsoil severe gear will be going into both axles as I have had excellent results with it towing heavy with my (now retired) Ford trucks.

I have to give a shout out to @rustyshakelford for graciously giving his time and resources on this endeavor—he donated the OEM covers, welded the threaded bosses into them, and brought the covers with some of his items to be powder coated (at a great price). A very stand-up guy (a true rarity these days) and I would highly recommend anyone in the Texas area needing lift/suspension alterations/upgrades to give him a shout.

Many thanks @rustyshakelford for everything!

I will post updates to this thread as I move along.

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[CarbonSteel]

I will preface this by saying – Ladies and Gentlemen, check your axle drain plugs!! I have 5K miles on my Rubicon and I could have easily removed these drain plugs with a ¼” finger ratchet. They were not tight at all and no way would they have remained in the axle for 50 or 75K miles without loosening and falling out.

Phase 1 of my project is now completed and the covers with the temperature bosses are now installed (another shoutout to @rustyshakelford for his time and resources). I have some stainless cap screws on the way to take the place of the OEM hex heads. The next step will be installing the gauges and wiring.

I did not find any surprises in either axle, though, I am not thrilled with how little capacity there is in each axle and I will change the fluid on a fairly conservative OCI. The vast majority of axle wear occurs during the first 15K miles and despite longer and longer runs, the wear metals will continue to drop and true to that statement, I found a fair amount of metal on the magnetic drain plugs on both axles, but more (as expected) on the rear.

The rear axle oil was very dark and loaded with metals (you can see a video of the oil here - . I believe the rear axle had synthetic 75W-140 in it as it appeared to be more viscous than the front axle which was likely conventional 85W-90.

The front axle oil was honey colored and this was expected since front axles rarely see the amount of use that a rear one will and mine (at least to this point) aligns with that premise.

Amsoil Severe Gear was installed in both axles with 75W-140 in the rear and 75W-110 in the front. I did not install 75W-90 because 75W-110 is the upper viscosity that 75W-90 used to be before the SAE J306 tables were updated some time ago.

UOAs of both axles will be done to set a baseline to compare against future OCs and both axles will only see Amsoil going forward as I have had excellent results with that oil especially when towing.

Here are some photos – enjoy!

Front Drain Plug:

Rear Drain Plug:

Clean Drain Plug (For Reference):

Front Axle Internals:

Rear Axle Internals:

Rear Axle Oil:

Front Axle Completed (with temperature sensor boss at top of cover):

Rear Axle Completed (with temperature sensor boss at top of cover):

 

[rustyshakelford]

Looks great. Interested in the temp results

Brett.

 

[Motoristx]

This is an interesting project. I’m definitely going to follow along, and would love to see the analysis at each stage.

I see you’re in Texas, so it’s safe to say you’re in a hot environment most of the year.

A few questions:
What type of driving do you do? It is mostly highway and little city, or mostly city with little highway? For example, I’m 80% highway and 20% city, even though I’m in the Houston area.

Are you an aggressive driver? flooring it all the time?

We have floods here in the Houston area, and I typically drive right on through the high water and I have to check my diff fluid every time. Is this also a possibility? If so I’m interested in seeing if water gets in and if there is a noticeable difference in temperatures before changing fluids.

Will you be tracking the temperatures of the differentials as you drive, to see how long it takes to get to operating temperatures? I guess some sort of data logging could help build a trend, but I’m not familiar with how to set it up.

Bryan

 

[Token]

Following...

I fully expect that the rear will see much higher temps, and a lot more often than the front.

You had the stock covers powder coated prior to installing them on the Jeep.

Both inside and out, or outside only?

 

[CarbonSteel]

This is an interesting project. I’m definitely going to follow along, and would love to see the analysis at each stage.

I see you’re in Texas, so it’s safe to say you’re in a hot environment most of the year.

A few questions:
What type of driving do you do? It is mostly highway and little city, or mostly city with little highway? For example, I’m 80% highway and 20% city, even though I’m in the Houston area.

Are you an aggressive driver? flooring it all the time?

We have floods here in the Houston area, and I typically drive right on through the high water and I have to check my diff fluid every time. Is this also a possibility? If so I’m interested in seeing if water gets in and if there is a noticeable difference in temperatures before changing fluids.

Will you be tracking the temperatures of the differentials as you drive, to see how long it takes to get to operating temperatures? I guess some sort of data logging could help build a trend, but I’m not familiar with how to set it up.

Bryan

I drive "normally" not flooring it every time, but (like my other vehicles) the Jeep will see extended times on the highway during the summer--we take multiple trips from Houston to CO/WY/MT and always heavily loaded or towing. The small capacity of the axles is a concern of mine which is why I installed 75W-140 in the rear and 75W-110 in the front.

A possibility for water to get into the axle due to the temperature probes? If so, it is not possible--the temperature probe is sealed and is made of brass with 1/8" NPT threads.

Yes; I will be tracking temperatures to understand how the axle operates under load and various temperatures.

Hope this helps!

 

[CarbonSteel]

Following...

I fully expect that the rear will see much higher temps, and a lot more often than the front.

You had the stock covers powder coated prior to installing them on the Jeep.

Both inside and out, or outside only?

Agreed; since the rear axle is in 100% operation versus part time and typically slow operation for the front. It was that way on my 2010 FX4 and my 2015 F-250 when towing in the mountains and in the snow, even with 4x4 engaged.

Yes; the stock covers were powder coated, but only on the outside and the gasket surface area on the inside. Long term, I will change these to aftermarket steel covers and am waiting to see who makes one with increased fluid capacity that (more or less) mimics the Spicer or ARB design.

 

[Motoristx]

A possibility for water to get into the axle due to the temperature probes? If so, it is not possible--the temperature probe is sealed and is made of brass with 1/8" NPT threads.

Just thinking, regardless of how it gets in there, wether it’s through the seals or the vent hose, I’d be curious to see if it makes a difference in the running temperatures.

I usually end up sticking a rod through the top hole and into the oil to see if it’s got emulsified water/oil after a flood.

 

[CarbonSteel]

Just thinking, regardless of how it gets in there, wether it’s through the seals or the vent hose, I’d be curious to see if it makes a difference in the running temperatures.

I usually end up sticking a rod through the top hole and into the oil to see if it’s got emulsified water/oil after a flood.

I see, well, (for me) if water gets into the axle it will only remain until I can quickly change it because it will ruin the bearings in short order.

 

[CarbonSteel]

Apologies for taking so long to get back to this, but my Ram Mount (https://www.rammount.com/part/RAM-DT-204-TRACK-A12U) was on back order for quite some time due to a production issue and the weather has been less than cooperative.

At any rate, I am in the "mock-up" stage of mounting the gauges (the positions, etc. are not finalized yet and I will likely change the cup bracket mounting screws to stainless socket head) and thought that I would share a few photos. I have to run the wiring from each axle and pass it through the firewall and make the necessary connections. I have not found a power source for the dash lights as yet but I am hopeful that I can find something that is easy to access. The great thing about ISS gauges is that you only have to run one set of power and lighting wires because you can piggyback between gauges.

Here is the front axle gauge - http://www.issprogauges.com/EV2-100-280-deg-F-Front-Axle-Temperature-Gauge-p/iss-r13522.htm

Here is the rear axle gauge - http://www.issprogauges.com/EV2-100-280-deg-F-Rear-Axle-Temp-Gauge-p/iss-r13511.htm

Here are the gauge cups - https://www.autometer.com/2-mounting-cup-black.html

More to follow soonest!

View From Driver's Seat:

View From Passenger Door:

 

[CarbonSteel]

The weather and life in general finally aligned and I was able to complete my project. After playing contortionist under the dash for several hours, my back is reminding me that I am still alive.


All in all, it was not an overly difficult task and my fish tape paid off in spades again as I routed the ¼” loom covered sensor wiring through the frame securing the loom with tie-wraps to the rear axle vent tube and the lower fan shroud housing above the front axle. I used the rubber firewall boot on the passenger side to pass the wires into the interior. Power was pulled from the ignition/accessory wire (pink/orange) in the upfitter wire pack under the dash and I tapped into the ambient lighting wiring in the passenger footwell, to provide the gauge lighting. A ½” hole was bored by hand using a drill bit to pass the wiring from under the dash to the gauge cups.


Speaking of the dash, it was necessary to remove the glovebox, the front bezel (it has the start stop button in it), and the 8.4” LCD panel to gain access to the space behind to route the wires. This trim tool kit was invaluable to removing everything without breaking anything (https://www.amazon.com/gp/product/B07RRNDBYG/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1)


Each sensor has two wires (power and ground) and the gauges require three (power, ground, and illumination) so there are total of 5 wires in the red & black braided loom (https://www.amazon.com/gp/product/B075VR7ZQS/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1) going into each the gauge cups.


I had considered fabricating some protection plates for the sensors (using the axle cover screws to mount them), but the sensors are fairly high up and tucked behind some of the suspension components so they may not be needed. I have a new Metal Cloak covers coming so I may look into that after I have them mounted. The temperatures sensors are mounted directly into the gear oil splash stream and they work very well thus far. I can confirm the ring gears do not turn in the front axle because it has not registered any temperatures at this point and I know the gauge is working.


The rear temperature when to 160°F during a 75+ MPH dash for about 20 minutes. I will see how the temperatures fare on a road trip whenever the lock down is over. At any rate, I am very happy with the results and like the aesthetics of the installation.


Enjoy!


Rear Axle Cover:

Front Axle Cover:

 

[D60]

Does FCA call out 75W-140 in the rear? I would have assumed lighter (but I really don't know)?

 

[CarbonSteel]

Does FCA call out 75W-140 in the rear? I would have assumed lighter (but I really don't know)?

Yes; they do for towing (and my Rubicon has the towing package). With that said, they factory filled it with 80W-90 and not 75W-140, which seems contradictory and stupid--particularly if a new Jeep owner does not get into that level of detail and assumes that is "ready to tow".

 

[D60]

Yes; they do for towing (and my Rubicon has the towing package). With that said, they factory filled it with 80W-90 and not 75W-140, which seems contradictory and stupid--particularly if a new Jeep owner does not get into that level of detail and assumes that is "ready to tow".

I'm not doubting you, but they state this I assume? I mean the manual or something says it comes with 80W-90 and the user should swap if intending to tow?

 

[CarbonSteel]

I'm not doubting you, but they state this I assume? I mean the manual or something says it comes with 80W-90 and the user should swap if intending to tow?

Here from the OM:

Based upon the results of the UOA that I did at 5K and again at 10K and the size of the sump, I would want the maximum protection that I could get and 75W-140 is typically it.

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