I don't understand, The correct name is DEXRON and always has been so I'm not sure why JLR would ever want to spell it DEXTRON. Is there proof that they have ever spelled it incorrectly?

Richard

 

My expert friend (ChatGPT) summarises it better than I ever could:

Because CHF 202 and Dexron III are completely different fluid types — chemically, physically, and in terms of system compatibility:

Property Dexron III CHF 202

Base type Mineral or semi-synthetic ATF Fully synthetic hydraulic oil
Viscosity (40 °C) ~35–40 cSt ~18 cSt
Additives Designed for automatic transmissions — includes friction modifiers and detergents Designed for central hydraulic systems — anti-foam, anti-oxidation, no friction modifiers
Colour Red Green
Seal compatibility Formulated for ATF-rated seals Formulated for CHF-rated seals (different elastomer spec)
Operating pressure/temp range Up to ~120 °C typical Up to 150 °C and much higher pressures


What happens if you mix or substitute them:

Seal swelling or shrinkage: the additive chemistry is different; CHF can cause old ATF-rated seals to shrink and leak.

Pump noise or failure: viscosity mismatch can cause cavitation or inadequate lubrication.

Steering feel issues: lighter CHF causes reduced assist or erratic pressure in pumps designed for ATF.

Potential corrosion: different inhibitor packages can react badly when mixed.


So in short:
→ CHF 202 ≠ Dexron III.
A steering system designed for Dexron III (ATF) must stay on that, flushed if contaminated.
A system designed for CHF 202 must never get ATF.

On the Jaguar X150 (XK/XKR 4.2 and 5.0), the workshop manual specifies Dexron III, not CHF 11S or 202 — those were for later electric-hydraulic or Land Rover systems.

 

Hmmm... firstly, why would you mix fluids?
secondly, there is no transmission in the power steering system.

 

But Trkyam did mix fluids which is why we're discussing it.

Richard

 

OH!! I see. Thanks.

Well, that's where I differ from others. I never mix fluids. And if there is a need to add... I perform and fluid and filter change, instead. (And investigate why on a sealed system, the level has dropped)

 

You mix fluids without realising it when the factory puts in ATF as per spec, but then also publishes a handbook advising to use CHF 202!

 

I'm gratified that my little thread is still alive after so long. Kind of like my car. Yes, despite my prolonged absence from the forum due to business pressures, the tired XKR is still happy and running well. It's had new rear anti roll bar drop links in the past year, and will soon need new front lower wishbones. Apart from that, it's all good. And driving it still reminds me of trying to take a Labrador puppy for a walk. And I did replace my steering fluid with Dexron...

 

But what happened to the DEXTRON spelling?

Richard

 

You can buy "Dextron 3" if you look hard enough

https://statuscarcare.com/products/s...-fluid-5-litre
https://forcemaxoil.com/atf-dextron-3/

Being in the UK, this reminds me of people who say "brought" instead of "bought" and "free" instead of "three", "pacific" instead of "specific" etc etc because they just think it sounds right

 

I appreciate that advertisers often make mistakes, in fact they're well known for it, but you said that JLR cannot spell and were using "DEXRON" when, presumably, you feel that they also should have been using "DEXTRON"? Why would JLR want to use the same incorrect spelling as a few illiterate internet sellers?

Richard

 

To try and close this out once and for all: the second edition workshop manual for the 5.0 states DEXTRON but the original one states DEXRON. Then, because I referred to the OP title and a misspelled product Google result (euro car parts) I too got them muddled up. I imagine JLR are also fallible and didn't do it on purpose.

The much bigger issue is the owner handbooks which incorrectly advise CHF 202, which will likely lead to premature rack failure. I have first hand experience of this the other way - My XC90 mk1 had ATF instead in the PAS when I bought it, but it should have been CHF 11S. I've since flushed out all the ATF but also had to replace the pump, and the rack itself is jerky and close to failure, no doubt due to damaged seals, but it's a huge job so I'm putting it off for as long as possible. That's why I'm hyper vidulent about getting the fluids right in my Jag.

 

Whoops! :-)

Hey! this is my thread! :-)

I hope everyone is having stutter free steering :-)

 

You're quite right. It was so long ago I'd forgotten. I withdraw my claim. :-)