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Saturday Night Racer >> RACE TECH >> Powerglide fluid questions
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Message started by dirt33 on 08/20/09 at 8:38am

Title: Powerglide fluid questions
Post by dirt33 on 08/20/09 at 8:38am

I bought a Hobby Stock in which the seller ran CAT tranmission/drivetrain oil in the Powerglide transmission. He swears up and down that this is the only thing that should be run in there.

1) Is there anything wrong with running AMSOIL trans fluid in there? AMSOIL has Super Shift Racing fluid that says it should be used in Allison C-4 or Ford Type F applications, and they also have Synthetic Low Viscosity fluid that is for DEXRON/MERCON applications. I assume a Powerglide should always take fluid that is designed for DEXRON/MERCON, correct?

2) Kind of a dumb question here, but how much fluid does a Powerglide hold? The trans in my car does have a homemade dipstick in the filler tube, but there are no marks on it anywhere. So, I can check the level all day long, but I don't really know what I am measuring against. The bottom of the dipstick goes about halfway into the pan, the pan itself is about 2" deep. Should the fluid be only full enough to fill to the top of the pan, or does it need to fill up past that?

Thanks.

Title: Re: Powerglide fluid questions
Post by benstrans on 08/20/09 at 9:25am

dirt33 wrote on 08/20/09 at 8:38am:

Not being familiar with CAT fluid, I looked it up.

It APPEARS to be formulated to eliminate clutch chatter and gear pitting. While these may be problems encountered by a tractor due to the tremendous forces being put up against it (tons of dirt being pushed at low rpm) I don't see why they'd be problems in a Powerglide dirt racer.

The only time you going to experience a major load on the clutches is DURING THE UPSHIFT. Once it's in high gear, the load is minimized.

The 'gears' are ONLY turning in LOW so pitting should be NO problem at all. It never was in a Powerglide.

As for fluid level, a good rule of thumb is to keep it right at the level of the pan rail. For a PG with NO converter, the fill should be about 4 quarts.

Title: Re: Powerglide fluid questions
Post by dirt33 on 08/20/09 at 9:43am

Thanks for the info ben, I have sent you a PM.

Title: Re: Powerglide fluid questions
Post by hogracer3d on 08/20/09 at 12:30pm

Mike's actually told me that a direct drive glide fluid cools off when in high gear and only builds heat when under yellow.

Probably not the case with a converter though.

He actually sells a blended fluid under his own label, but it is more the consistancy of the old type F than Dexron

I under the new Dex 6 is a synthetic

Title: Re: Powerglide fluid questions
Post by benstrans on 08/20/09 at 4:08pm

hogracer3d wrote on 08/20/09 at 12:30pm:

In MOST automatic transmissions, the converter is the big heat generator. Therefore, in a converterless 'glide there should have VERY little heat.

However, there IS some friction caused by drag from the reverse clutches. Most race 'glides are built with a VERY loose rev clutch lined plate clearance. This is going to drag in BOTH Low and High gears, but NOT generate much heat.

I've seem some that have NO plates at all, but they back up VERY poorly.

IMCA rules state that you MUST have reverse, but they don't say how good it has to be.

Title: Re: Powerglide fluid questions
Post by dave_lewis on 08/21/09 at 6:56am

Back in '90 when we first started using glides we tried a bunch of fluid types.
The best was "hytrans" fluid. I am sure it is similar to the cat fluid.
The info above is all good regarding heat buildup and such, not using a convertor really cuts down on heat.
The tractor fluid will not change color or break down unless something goes really wrong with the trans.
Dave