I already searched on the net, and found that some people have the same concerns about painting a transfer case (TC) as I do:

I just removed my TC and made it very shiny (with wire brushes. Normally I would spray on a clear coat now (just like I did it with the air-intake of X-Type and S-Type).
But I am afraid that this layer of clear coat would hinter heat dissipation, and thus might lead to a damaged TC sooner.
I have the same problem with the transmission.

Does anyone have an expert insight into this problem: To paint or not to paint?

 

Not an expert, but common reasoning says no. Thus why Jaguar themselves put the "air scoop" that constantly gets broken off especially driving in snow to "scoop" cooling air on the transfer case.

 

Thanks, Dell. So I will probably not spray paint the TC, even though it is tempting. My air scoop is also missing, and I live, where Snowmans are as rare as Yetis...

And has anyone opinions about the transmission (Jatco JF506e)? To paint or not to paint?

 

Peter, I would say to paint it. It is not like you are racing it and are pushing the temperature limits of things. Yes, things may run a few more degrees warmer, but a few degrees is no big deal. If you were looking to put something like Rhino Lining on it, then I would say no. As long as you keep the tranny temps under about 180F, you will be just fine. Get up over 180F, the life of the tranny starts to drop like a rock time wise. The higher you go, the shorter the life. You get it up around 300F, you have minutes of use left.

 

Hi Peter,

Just to add my two cents, given the harsh environment in which the TC lives, any finish you apply is likely to take a beating, so my instinct would be to save yourself the trouble and leave it unpainted.

If you decide to paint it, a high-quality high-temperature engine paint would be most likely to survive. I have used the auto-store rattle-can engine paints with various degrees of success. The best long-term results I have had were with the POR15 system of metal prep and top coats. ( por15.com ) These products are not inexpensive, but they are easy to apply, look great, and are very durable.

If heat is a consideration, there are some arguments that black and other dark colors will not dissipate heat as effectively as white or other light colors, such as light gray or aluminum metallic silver. Also, I have read that, at least on engines, a thin coating is prefereable to a thick one, so you probably wouldn't want to apply three coats if one or two light coats would suffice. Of course, most of the engines we deal with are water cooled, unlike most transfer cases, so that's another factor to consider.

I'll be anxious to learn what you decide to do.

Cheers,

Don

 

Hi Don, nice to hear something from you. I am still a bit undecided, but to clarify: The "painting" I am considering is not with "paint" as such, i.e. no black, white or gray, but a thin layer of CLEAR coat to preserve the shine, which is currently shinier than new. It was a bit of hard yakka (Austr. for hard work) to give the TC the current shine:


The idea would be that the thin layer of clear coat protects the aluminum from oxidation (corrosion) and keeps the shine. So far I just used the clear coat on the TC on the hub that connects to the prop-shaft (right in pic) and the plug (centre of pic) and the nut-cover (on the other side).

Hi Thermo, thanks for you input. It was not clear, if you would "give the go ahead" to a thin layer of clear coat sprayed on in regards of the TC or the tranny only...
I have no way of measuring the temps (not that I know of... OK I actually, could, but only after reassembly, which would be either when it's painted or not painted. I could just simply attach the external THERMOelement ( ) on a wire of a thermometer with silicone to the TC or tranny... Or measure after drive.
Also, I used your temps and converted them into Celsius, so that I can understand them: 180F = 82°C and 300F = 149°C

The gear oil for the TC is supposed to be synth. 75W-140, I will use 80W-140, as the 75 one is very hard to get in Australia, and probably for good reason: No need for 75 on Australia, as it is never really cold in Australia. 75W describes the oil properties/suitability at low temps, specifically 0°C. 80W is a touch more viscous (thicker) than 75.
Also interesting for those, who wonder (I have seen them wonder on youtube) why e.g. a 75W-90 gear oil seems to be so "liquid" and not much thicker then engine oil...: They have a different grading system for gear oil and grad 90 gear oil has about the same viscosity as 40 to 50 grade engine oil.

After that short excursion:
When I bought the Jag, the PO told me after I bought it that he made a TC oil change not long ago. He had no reason to lie. The oil I pored out of there was like tar with metal dust in there... He used the method of changing the oil, where you raise the Jag up to a ridiculous angle on one side. This tells me two things: This method of changing the TC-oil is inadequate (as the old crap does not come out) and that there is a really though environment in the in the TC. So I think, I just made my decision: While I want to apply clear coat on one hand, I really should not. The compromise would be to apply a very thin layer of clear coat on the underside, which is visible, when looking under the car and do without coating on the upper side of the TC.

Btw.: The odometer shows 160.000km and the TC was not the OE one, it was a replacement part from the wreckers. I know that, because I saw the typical wreckers-marks on the TC (yellow scribbling on the TC).

 

Ah! So I was confused by the term "painting," which is certainly correct, but when we paint something in the U.S. with clear paint, we tend to use the term "clear coat." I understand your desire now. Your TC certainly does look brighter than new! You've done a lot of hard work.

Cerakote makes several options in clear coatings with either matte or gloss finishes. Check their temperature ratings:

Cerakote Clear Coatings

Some of the companies that offer high-temperature engine paint in spray cans/rattle cans offer clear. In the U.S., common brands include Dupli-Color and VHT. Here's one example:



Cheers,

Don

 

Thanks, Don, that helped. I know that it is called clear coat - same here. But I was not aware that there are special clear coats for engines and higher temps.
So I went and quizzed the net. I found what I need on the net, purchasable in a shop just 2km away, even better than what's in your second link. The "Dupli-Color Engine" there goes up to 500F, but I found "Dupli-Color High Heat Ceramic Paint Clear 340g" Spray can, and the clear coat is designed to withstand temperatures of 2000 degrees F.

The important thing that's part of "Dupli Color Engine" is that there are ceramic resins in there, and that's good for heat dissipation. After long search it looks like the same ceramic resins are also in Dupli Color High Heat, and it even says on the can "Ceramic".

PS: I just ordered in that shop around a corner (Repco) 4 cans of High Heat Clear (they have to get it in). There currently on a 20% off special for AU$20.80 each. That product is for exhaust systems, too. I may just try that once (2000F are 1093°C).

 

My understanding is that ceramics (non-metallic solids) are poor conductors of heat and therefore good insulators. At least that's the claim of the ceramics in the coatings they use on exhaust manifolds. If so, the ceramic-loaded paint may slightly reduce heat dissipation from your transfer case. But the difference should be minimal if you keep your layers thin.

I don't see any lines to an external cooler and no heat fins cast into the case of your TC to suggest the engineers were overly concerned about heat management, so it's unlikely you will cause any problems by coating your TC.

We'll look forward to seeing the results of your efforts.

Cheers,

Don

 

Hi Don,

> ceramics (non-metallic solids) are poor conductors of heat and therefore good insulators.

I see, where you are coming from: Just thinking of the ceramic tiles on the Space-Shuttle, but on the other hand, I just asked my wife, if she thinks ceramic is a good or bad thermic conductor - she said, a good one, and she is the cook - i.e. thinking of ceramic pots for the hot plate...., hence I investigated further:

https://global.kyocera.com/fcworld/c...cularly%20well.

Hence it all depends. Ceramic ≠ Ceramic!

Thus, when Dupli Color states regarding the "Engine paint" that it has good heat dissipation due to the ceramic resins...:
https://www.duplicolor.com/product/e...-with-ceramic/
I just assume that the ceramic, which is in Dupli Color High Heat has the same properties...
And I just found this finally confirmed in the description of this "for sale listing":
https://vgautopaints.com.au/products...olor-high-heat
where it says: Formulated with ceramic resins to provide maximum heat dissipation

As for the heat fins on the TC (which are refereed to as "heat sink" in electronics): Oh yes, there are there - they just were not visible in the view of the TC shown above...:



That's the view of the TC as it looks from underneath.

Also: Design intend was that more air is being funneled towards the TC. A very poor design-intent though, as this was meant to be achieved by a plastic air-scoop mounted underneath the TC, and I think that the majority of those scoops flew off the X-Types over time. Mine is missing. I will recreate some kind of scoop, when I am finished. If nothing more sophisticated crosses my mind, a modified black 1L bottle (or smaller, like a brake fluid bottle) might do...

I also suspect that the gear oil transformed into this tar-like gum due to insufficient cooling... But I am out on a limb there, as I cannot be sure, what kind of oil POs stuffed in there... I suspect that 75W-90 gear oil might degrade early, as 75W-140 is recommended.

Currently I put accidentally semi-synthetic 75W-90 gear oil in my rear diff, which should also be synthetic 80W-140. I will leave it in there for a while and than change it again.

 

There is actually a post in this forum I read years ago of a member fabricating an aluminum scoop with directions and dimensions. It's mounted with just that little screw so the reasoning was it would "pop" or aluminum would bend if hit excessively not causing damage. Obviously, the reason rarely is there the plastic one is because it's so freaking weak and the replacement price is just plain stupid.

 

Sounds like an idea, but I would be concerned, still: If the little screw is the "Sollbruchstelle" ( just had to look that up, but in English it's the same word: Intended breaking point) I would think that it might rip out the thread in the Aluminum of the TC or even rip out a bit of the TC, unless you use plastic bolts, which you really can't there, as it is getting too hot.

 

Here it is =

https://www.jaguarforums.com/forum/x...t-scoop-15934/

 

Thanks Dell, I'll give it a thought.

 

Peter,

That first link you posted is very good info. Apparently some ceramics have good thermal conductivity and some do not:

https://global.kyocera.com/fcworld/c...cularly%20well

The photo of the underside of your TC does show the heat fins, so you do want to be careful not to hinder heat dissipation with whatever coating you select.

Cheers,

Don

 

My two cents: I honestly don't think painting it with clear coat or honestly anything else would make much of a difference. If these parts are so finicky that an added little bit of solvent pigment and glue would ruin them then I'm not sure what to think. I think one of the main reasons they aren't painted is because of where they're located and manufacturers are just sort of probably like well why would one do that? And they are probably right on a mass production scale but as far as customization goes, do what you will. I mean sure as someone mentioned above don't put a rubber coating on it or anything.

Coming across you're mentioning doing this with the intake manifold was fairly serendipitous because I was just looking at my auction save x-type thinking what I could do to make it look better than it's Matte and dirty aluminum self and your idea of clear coating it, well I right like that. I will be taking it apart cleaning it, changing the gaskets anyway.

 

> Coming across you're mentioning doing this with the intake manifold was fairly serendipitous
Here is a word, I had to google: "serendipitous". Good one!

I searched and found 2 nice pictures for you of my made-shiny X-Type air-intake:


I did that a while ago and it still looks the same...

 

Peter, PAINT AWAY!!!!! Like others have said, just don't go crazy putting on heavy coats. yes, I see a little bit of insulating (non-heat conducting) happening with the paint, but the effect is going to be minimal (2 degrees celcius). So, not going to have any detrimental effect. If you were racing the car, then that is a different story.

 

Yes, thanks Thermo, I will spray-paint a thin layer with Dupli-color HIGH HEAT clear coat, which contains ceramic, which improves heat dissipation.

PS:
Before I started working on the X-Type again due to oil leaks, I "polished" (with wire brushes) another transmission and painted it with normal clear coat spray:

Before I "polished" it, it looked quite horrid. It's from my 26 year old van, which also had oil leaks, but no more. I wasn't too worried about heat dissipation there, because it hangs in the airflow in the middle under the car and does to get pounded with the heat dissipation from the engine too much.

 

Hi Peter, The T/C is too shiny to put back. mount it on a stand and admire it.
DB Noosa