Well I finally got around to getting my '97 GMC 1500 back in running
condition after sitting for more than 4years.
Had it up on the lift for to change the oil and check the fluids.
Trans is low, so I'm looking in the manual and it calls out
Castrol Syntorq GL-4 transmission fluid. ????????
What the heck is that?????? The kids at the parts counters
don't have a clue and the dozen or more sites and forums I've
been to all have a different opinion. One says use ATF, another
says 10w30 and crapola like that.
So what are some opinions here on the 'Bolt, I can always
count on enough replies, that I can pick out the most logical
one from the batch?
From the name, I would assume that they're calling out a
"synthetic" syncromesh trans fluid? Obviously with a GL-4 rating.
But what do I look for at the Farm & Fleet or Advance Auto or NAPA
and in what viscosity???
I tried running a Mobil Delvac 50w synthetic with a GL-4 rating in my SM420
a few years back.
http://www.pbase.com/dennygraham/image/166411769 It was just way to slick
for the old syncro's to get those big old heavy gears to movin'. They just didn't
grab like they should and if I didn't shift very sloooowly and give the gears a chance
to catch up it would grind, which it never did with the plain old Mystic 80w140 gear oils
from F&F that I've always used, and it shifts just fine after swapping back to the old school
gear oil.
Here's a very good paper on the differences between the GL- series
of gear oils used in syncromesh transmissions:
http://www.widman.biz/uploads/Transaxle_oil.pdf Denny G
Up in the air......till I get the trans fluid changed.
