<VV> What ATF?

[Joel McGregor]

Granted a Corvair Powerglide isn't the same as the big cars but a lot of racers have put way more power through them than a Corvair engine ever will.
Glad the additive helped your trans.
What is Dexron-5?

Joel McGregor


________________________________________
From: Jim Davis [jld at wk.net]
Sent: Wednesday, April 08, 2015 5:52 PM
Subject: Re: <VV> What ATF?

Although I have been repairing Corvairs for 51 years, I bough my first
PowerGlide car in 1996.  It was a 1966 Monza with the 140 engine and
A/C.  I rebuilt the PG and never had a problem.  In 1999, I bought an
UltraVan, 110 engine and PG.  I changed to a 140 166 cuin engine with a
140 PowerGlide (with ATI HD clutches) in 2004 and noticed the low band
would slip if I applied more than 3/4 throttle from a full stop.  I
tired adjusting the TV rod so that the secondaries would be barely open
when the TV valve was in the kick-down detent, as well as turning up the
idle pressure to 58 psi.  I was running Dexron-5 at the time.  Not much
help.  I just learned to ease off from a stop. There was a considerable
surge from low to drive and light throttle when the trans fluid was over
210 F; although it shifted fine at moderate throttle.  I thought the low
band might have hardened from over temps by previously owner, so I
installed a new Clark's rebuilt low band - no help.  Finally I bought a
NOS front pump from Clark's and installed it with no help.   Finally I
changed the 140 valve body from the car to the UltraVan.  Again no help.
   In the UltraVan, I change the engine oil, drop the PG pan and blow
all the oil out of the torque convertor using Bob Ballew's technique and
change the gear oil in the diff every spring.

  I went back to Dexron-3 in 2005 and it helped greatly, but I was
worried about the trans temperatures.  Out west, climbing the Rockies  I
often spend 30 to 40 minutes at full throttle in low range at 4,000 to
4,500 rpm getting the 5,400 lb coach up the mountains.  250 F is not an
uncommon trans fluid temp (measured in the oil cooler line going to the
B & M Hi-Tec oil cooler by a good Intellitronix digital gauge) in the
mountains in July.

I built as 190.5 cuin engine in 2007 using Ray Sedman's AP-500 cam;
Michael Leveque did the work on the heads.  That moved my max torque
into the 180 ftlbs range.  I talked to Mike Dawson at one of the Wichita
Tunas, and he recommended I try Dexron-6 with 10 oz of Trans-X.  It
worked as adverticed.  No slipping or shuttering of any sort.  I can now
floor the throttle from a standing start with out fear of low band
slip.  Shifts are immediate at 4,900 rpm, almost jerky, at full throttle
entering the Interstate. All this is imperical info; just what worked
for me - your results may vary.

Jim Davis

On 4/8/2015 4:27 PM, Joel McGregor via VirtualVairs wrote:
> As someone that rebuilt transmissions for years and knows a guy that used to write manuals & do research for ATRA - I use Dex VI in everything  (friend agrees).  I've never seen a fluid that would make a transmission slip.  The different properties would make the shift feel different if it wasn't designed for that particular oil but that's it.  B&M used to recommend type F for everything.
> I use VI in everything from TH250s to my wife's Saturn.  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