Gear oil GL-1 vs GL-5


[Follow Ups] [Post Followup] [Dodge Power Wagon Forum]


Posted by D Sherman [72.47.9.228] on Monday, October 17, 2011 at 22:18:59 :

Third thing on my big city shopping trip today, after trying to fight a no-seatbelt ticket, was to go to the oil place and get some 90W gear oil for my old trucks. I've been running 85W-140 in everything for almost 10 years now because I got a bunch of 5 gallon cans of it from the DRMO and then 55 gallon drum at a yard sale. The trouble is it's just too thick for a light truck. I especially notice it in my '67 Chevy on a cold morning (zero is cold here, but anything below 20 and it feels pretty stiff).

He looked up old Dodge and Chevy in his book of factory-recommended lube and said that GL-5 is okay for the Chevy transmission, despite it having synchros, but for Dodge prior to 1954 they list GL-1 and after 1954 it's GL-4. He says definitely do not use a higher GL number than recommended or it will shift hard and eventually damage the synchros.

So, I bought a bucket of GL-1 ($77!) just for the old M37 transmissions. I'm assuming GL-4 or 5 is okay for the differentials in everything since they don't contain any brass.

But I'm left with a couple of questions. First of all, what do guys really run? Does anyone go to the trouble of finding GL-1 gear oil or do they just use whatever's on the shelf at Autozone or Wal*Mart? (GL-4 or 5)? How bad is it really to use EP gear oil in and old tranny? The stranger question is what changed with the civilian Dodge transmission in 1954 that made them switch from GL-1 to GL-4 oil? I thought all the 1950s civilian trucks and straight-cut unsynchronized trannies so there shouldn't be any issue with EP additives (sulfur) causing any problem. This oil guy really seems to know his stuff, so I tend to listen to him. I was surprised to see 85W140 listed in the book as an acceptable gear oil for 1950s Dodges at temperatures above 80 degrees. I thought it would be too thick at all temperatures.



Follow Ups:



Post a Followup

Name:
E-Mail:
Subject:
Message:
Optional Link
URL:
Title:
Optional Image Link
URL:


This board is powered by the Mr. Fong Device from Cyberarmy.com