<VV> What ATF?

[Joel McGregor]

Trans fluid every 3K...

Remember the horrible 700r4 (4L60) from the early 80s?  They did a myriad of changes over the years to keep them from self destructing and I rebuilt a ton of them.  I've got a friend that bought a new '85 SWB Chevy and ran various supercharged and or nitrous systems in it for well over 100K and never did anything to the transmission except change the fluid every 3000 miles.  Those transmissions rarely held up for long behind a stock 305.  I've been changing mine with every oil change ever since he told me what he was doing and I haven't had a transmission problem since.  I've destroyed plenty of 4L60s myself.  The only one I have now is a 4L60E in a '93 pickup that now has over 200K on it.  I wouldn't say the transmission is great but it does still work and it didn't start getting changes that often until it had over 100K on it.

I've got an '82 V8 Malibu with a TH250C in it that was slipping in reverse when I got it.  After about 3 or 4 changes it quit slipping and has been working fine for years now.

I had an '04 CTS that you aren't supposed to change the fluid in that was acting odd at about 60K.  After about 5 or 6 changes it started working fine and last I heard it had almost 170K on it and was still working fine.

I would guess that Corvair automatics run a lot hotter and would really benefit from frequent changes.  I've never had a temp gauge on one.

One big issue with automatics is that you can't change very much of the fluid at one time.  I know a TH350 uses around 11-12 quarts and you only get 3.5-4 on a change if I remember correctly.

It would be interesting to send my fluid to a lab to measure the condition after 3000 miles.

I know my Corvair manual transaxles shift better after a 3K lube change.  I used to do them every 1500 miles when I drove them harder.

I'm sure my stuff will blow up after writing this.



Joel McGregor

________________________________
From: BobHelt at aol.com [BobHelt at aol.com]
Sent: Wednesday, April 08, 2015 5:23 PM
To: Joel McGregor; virtualvairs at corvair.org
Subject: Fwd: <VV> What ATF?

WHOA here Joel.
Change  PowerGlide lube every 3000 miles? Why?
Tell us the story.....
Bob Helt

________________________________
From: virtualvairs at corvair.org
Reply-to: joel at joelsplace.com
To: virtualvairs at corvair.org
Sent: 4/8/2015 2:27:42 P.M. US Mountain Standard Time
Subj: Re: <VV> What ATF?

All of my running Corvairs have manual transmissions so I haven't run it in a Corvair yet but I will if I ever drive an auto.
I also change it every 3000 miles.  That's much less trouble than rebuilding the transmission.

Joel McGregor