Randy Bobani

You have that backwards. It's pretty well known that power steering fluid contains much more calcium and much more zinc/phosphorous than ATF. There really isn't much of an additive package in any ATF. The only significant difference in ATF types is viscosity. The reason why ATF is more common in power steering units today is simply because it's cheaper.

awg

(From XJ 95 FSM Page 30 Chapter 1)

FLUID SPECIFICATION
Use MOPAR Power Steering Fluid, or an equivalent
product

Is that so it will have harder bones when its old

318SixPack

Slightly off topic, what size is the low pressure line? Might be close to replacing the one from the factory, but need to make sure the store has rubber line of the right size before removing it.
and I use Prestone (synthetic?) PS fluid

Randy Bobani

3/8" ID

Morat

I have straight ATF in mine. It was a new PS Pump. Actually the second new one. The original pump died, probably due to a total lack of maintenance in 130k miles. The fluid may have been Mopar power steering fluid once but it was black caramelised treacle by the time it reached me.
The first replacement pump ran straight ATF which looked a lot better than the stuff the original one ate for 140k but the pump died in about 6 months. At the time I wasn't sure if that was because it was Chinesium (complete with Chinese characters on the filler cap and no English) the plain ATF, or a combination.
So when the third one went on, I thought hard about buying the expensive stuff but seeing as the Chinese replacement sounded like a steam train from the moment it went in (which I wrongly assumed was the Aircon Compressor until I realised that the power steering was getting really heavy) in the end I went with straight ATF and this one has been fine for over a year now.
Will it last 140k? maybe not - but I'm pretty swift at changing the pump now.

robsjeep

if the pump died, it have have shed metal bits, which can damage the gearbox, which in turn may now shed metal bits which will eventually kill it and the new pump.

I run a magnafine brand power steering filter on the return line. you may wish to consider that. also be sure to flush the old fluid out real well for best chance at longest service life.

Morat

It was well flushed, but the filter is a good idea - thank you! I'll search one out.

Edit: Well look at that - Amazon.co.uk have one with 3/8" ID for thirty quid

4.3L XJ

That is the same as in the TJ FSM

Identical language in the WJ FSM

RocketMouse

[QUOTE=awg;3635806](From XJ 95 FSM Page 30 Chapter 1)

FLUID SPECIFICATION
Use MOPAR Power Steering Fluid, or an equivalent
product

That's a solid point there awg.... and very true, I have seen it in places like that, but I've also heard that it depends on the model year too. Maybe I'm wrong, but I've heard and seen that written in a few places before. And I agree, sometimes things in the FSM are there for a very good reason and you use something else it's at your own risk kinda deal.
Other times, I think occasionally the "factory" wants to promote a certain type or brand just to get a few bucks going back their way in the parts/service category... when a different aftermarket solution is actually either better or cheaper.