Hydro assist fluid

xjmarc · Nov 2, 2016

So I've heard to use ATF, power steering fluid and hydraulic fluid, so what works best. It's in a Jeep XJ.

pholmann · Nov 2, 2016

I use 303 hyd fluid in my full hydro.

70Scout · Nov 3, 2016

If it is hydro assist I would run what ever you have been running for your power steering.

blugreenformula · Nov 4, 2016

Out west we all ran hydro assist or full hydro. In the summer (115 degree during the day), Royal Purple ATF was all we found that wouldn't boil and puke out of the reservoir. Wasn't cheap, and the hydro setups were anything from complete PSC systems, with big coolers, down too stock Toyota pumps with surplus center rams and cheap coolers.

https://www.amazon.com/Royal-Purple-12320-Performance-Transmission/dp/B000BQ4WZ2

kmcminn · Nov 4, 2016

I run atf and have for years.

clemsonjeep · Nov 4, 2016

The ATF vs. Power Steering Fluid thing depends on the pump and box you're using. Some have seals that don't deal with ATF very well...or vice versa.

I've been running the run of the mill Valvoline Power Steering Fluid you can buy at any local parts store. If you pull up TG's site or PSC's you will typically find a note recommending full synthetic OR standard fluid. Being that I would prefer not to blow a line and pour $75 (wild ass guess) worth of fluid all over the rocks I choose to run standard fluid.

I just ran my rig all day at Harlan...on the toughest trails there in 75+ temps. Keep in mind I also have a turbo under my hood which aggravates the temps. There was no whining, squealing, loss of power, etc.

Just because full synthetic is "better" doesn't mean its for everyone. The tractor hydro fluid can become a problem in cold weather too depending on the weight (viscosity) of the fluid.

xjmarc · Nov 4, 2016

Well it's a stock, for the most part, pump (Jeep XJ) and a Durango box with a surplus center ram with a small finned cooler. Guess I'll find out tomorrow at Chocolocco.

clemsonjeep · Nov 4, 2016

I believe the factory service manual says not to use ATF for the factory parts.

xjmarc · Nov 4, 2016

Forgot to mention I put power steering fluid in it.

bigs10blazer · Nov 4, 2016

i run full hydraulic on one rig(43 stickies and a farm ram) and ram assist on a toyota and 36s,, and a bouncer on 43s and a double ended ram, i run atf with B&M trick shift fluid (50/50 mix)
ran this combo for years, always works good, no whining or squealing , at smorr a couple years ago , 104 degrees , never once gave me a problem,
i am not a royal purple fan, i would stay away from it.