New power steering gearbox fluid? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Daron65 · 04-21-2020, 06:53 PM

Im in the process of installing a rebuilt power steering gearbox on my 71 truck. The box is a 73 rebuilt box.
Im going to flush the system before I remove the old box. What fluid do you guys run? Do you use power steering fluid or ATF? Is one better than the other?

Thank you

**tdangle** · 04-21-2020, 07:23 PM

When I put my new engine in I had to refill the power steering system. I just used dexron ATF. No issues or foaming as some have reported when using PS fluid.

BCOWANWHEELS · 04-21-2020, 07:26 PM

P/s fluid is for steering...............atf is for trans..............so simple,,,, why a 73 box

Daron65 · 04-22-2020, 07:17 AM

Quote:

Originally Posted by BCOWANWHEELS

P/s fluid is for steering...............atf is for trans..............so simple,,,, why a 73 box

Im using a 73 box because I was able to get it from a local store.

I Ask about the fluid, because my friends 72 c10 states to use ATF on his OE power steering pump dipstick. Just a little confused.

**special-K** · 04-22-2020, 07:49 AM

The two are so much about the same thing the difference is a small difference in viscosity, just like motor oil. P/S is thicker/heavier but not enough to cause seal issues. Often when a seal starts leaking using ATF will halt the leak that P/S was allowing

rpmerf · 04-22-2020, 09:16 AM

I used PS steering fluid. I made sure to get one that did NOT have any stop leak stuff in it.

Check any manufacturer instructions, and follow them. Don't want to have it fail, try to warranty it, and they blame the fluid. Might be able to find it on the manufacturer's web site.

Here is how I did the flushing:
Put the pressure hose into a jar
Fill up the resivoir
Put the PS belt (or whatever belt I have around) around the chuck on a drill
Spin it until the resivoir was almost dry
Repeat until the fluid flows clean
Try not to let it run dry

I didn't want to do it with the engine running for fear of running it dry, and trying to fill it with the fan spinning.

Note that the 73 box should be 3.5 turns lock to lock vs 4.5 turns in the original box. 3.5 turns feels more natural to me. 4.5 turns felt like I was steering a pirate ship.

BCOWANWHEELS · 04-22-2020, 11:00 AM

yea but the 3.5 box is more darty when driving it.

04-21-2020, 06:53 PM	#1
Daron65 Registered User Join Date: Oct 2019 Location: Monaca, PA Western PA Posts: 93	New power steering gearbox fluid? Im in the process of installing a rebuilt power steering gearbox on my 71 truck. The box is a 73 rebuilt box. Im going to flush the system before I remove the old box. What fluid do you guys run? Do you use power steering fluid or ATF? Is one better than the other? Thank you __________________ 1971 Chevrolet C20, Blueprint 355. Holly Street Avenger 430HP. Turbo 350 1952 Chevrolet Deluxe. Stock. True survivor with 1 paint job 1953 Buick Special. GM 355. Just a good smooth engine.

04-21-2020, 07:23 PM	#2
tdangle Senior Member Join Date: Mar 2005 Location: Jurupa Valley, Ca Posts: 1,210	Re: New power steering gearbox fluid? When I put my new engine in I had to refill the power steering system. I just used dexron ATF. No issues or foaming as some have reported when using PS fluid. __________________ Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC

04-21-2020, 07:26 PM	#3
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: New power steering gearbox fluid? P/s fluid is for steering...............atf is for trans..............so simple,,,, why a 73 box __________________ I BELIEVE IN JOHN 3:16

04-22-2020, 07:49 AM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,862	Re: New power steering gearbox fluid? The two are so much about the same thing the difference is a small difference in viscosity, just like motor oil. P/S is thicker/heavier but not enough to cause seal issues. Often when a seal starts leaking using ATF will halt the leak that P/S was allowing __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

04-22-2020, 09:16 AM	#6
rpmerf Registered User Join Date: Feb 2011 Location: Parkville, MD Posts: 1,024	Re: New power steering gearbox fluid? I used PS steering fluid. I made sure to get one that did NOT have any stop leak stuff in it. Check any manufacturer instructions, and follow them. Don't want to have it fail, try to warranty it, and they blame the fluid. Might be able to find it on the manufacturer's web site. Here is how I did the flushing: Put the pressure hose into a jar Fill up the resivoir Put the PS belt (or whatever belt I have around) around the chuck on a drill Spin it until the resivoir was almost dry Repeat until the fluid flows clean Try not to let it run dry I didn't want to do it with the engine running for fear of running it dry, and trying to fill it with the fan spinning. Note that the 73 box should be 3.5 turns lock to lock vs 4.5 turns in the original box. 3.5 turns feels more natural to me. 4.5 turns felt like I was steering a pirate ship. __________________ 1970 C20 Custom Camper - 350, TH350 1997 GMC Suburban 1994 Acura Integra GSR 1987 Dodge Daytona Shelby Z

04-22-2020, 11:00 AM	#7
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: New power steering gearbox fluid? yea but the 3.5 box is more darty when driving it. __________________ I BELIEVE IN JOHN 3:16



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