The Stovebolt Site Forums The Shop Area Driveline New Venture 3500 (NV3500) trans fluid????

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.

NVG3500 (bellhousing is frt half of case) uses G.M. 12345349 fluid, NVG 4500 (case iron man housing, separate bellhousing) uses G.M. 12346190 (Castrol syn-torq).

Got that already from the service manual BC. And it's a NV3500, Those
numbers translate to a synthetic 75w90 GL-4 from what I can sort out,
Problem is you can't find any synthetic 75w90 GL-4 syncromesh fluid at any of the
farm stores or any of the multitude of auto stores in the area. Even hard to find it on line.
Taint payin' $30 or $40 a quart for the stuff at a GMC or Chevy dealership.
All, and I mean all, of the parts store guys say they sell the "Pennzoil Syncromesh
Transmission Fluid" to any and all for manual transmissions and that's the only product
they carry for manual transmissions. The Oil change shops say the same thing.
That Pennzoil is a GL-3 oil and it's not a synthetic....if that's what's still in the trans
after 20 year on the road.
dg

12345349 bottle says its "partially synthetic", bottle of Valvoline 811095 says synthetic, will replace both 12345349 & 12346190, NOT! I think the Valvoline would work in a NVG 3500 but not a 4500 as it has non-brass syncros.

Here is what Amsoil sells for that. I searched it with the 5.7L. Didn't know what engine you have. I like their products alot. Not always cheap though.

Amsoil Manuel Trans Fluid.

I'll keep that in mind. They do seem to be the only ones that make claim that their gear oil
has a straight GL-4 service rating.
I've never bought any Amsoil products. Always thought it was a scam because you never
saw it in any of the retail stores.
There was always lots of build up for twice as much for what seemed d to be the same stuff
all the other really "big" oil company's were selling. If they had discovered some sort of magic
formulas, I'm sure big oil would have stolen it by now.
tks,
dg