Author Topic: Gl4 vs GL1 gear lube  (Read 1370 times)

Offline robert G. smits

  • Cad58y CLC 2426
  • Posts: 179
  • Name: Robert Smits
Gl4 vs GL1 gear lube
« on: August 30, 2017, 12:52:20 PM »
After researching this subject I am still confused about the acceptability of GL4 gear lube in a 41 manual transmission.  Help appreciated.  Bob Smits #2426
R. Smits, #2426
23 Cad 7P Touring
32 Cad 5P Coupe
38 Cad 90 Series
41 Cad 63 Series
58 Cad Eldo Barritz
The average man can take care of one Woman and two Cadillacs, Al Edmond AACA Past President

Offline Jim Miller

  • Posts: 285
  • Name: Jmiller
Re: Gl4 vs GL1 gear lube
« Reply #1 on: August 30, 2017, 05:55:13 PM »
Bob,
I purchased my 41 in March and wondered the same. After a lot of research I went with Redline MT90 GL-4. It runs fine and actually shifts better. I had some catching going from first to second gear and that is gone. It is a synthetic. Until I purchased this car I never realized the various oils and complexity. It's like taking in data from a firehose. Hopefully a more experienced club member doesn't come back and tell me my transmission is going to drop out onto the pavement.
Jim Miller
PS - everything I read indicated that GL 1 thru 4 would contain components that would protect any yellow metals that may be in the transmission- but never put a 5 in our cars.
« Last Edit: August 30, 2017, 06:31:50 PM by Jim Miller »
Jim Miller

1941 6219
1949 6237X
2021 XT6
Past:
1991 SDV
1999 DeElegence
2006 DTS
2013 XTS
2016 SRX

Offline robert G. smits

  • Cad58y CLC 2426
  • Posts: 179
  • Name: Robert Smits
Re: Gl4 vs GL1 gear lube
« Reply #2 on: August 30, 2017, 08:20:39 PM »
Thanks Jim.  In researching old threads one member had used GL5 for 50K without a failure.  Others say to only use GL1.  I have used GL4 for the lase 5500 miles since purchasing the car in 08.  The PO wasn't mechanically inclined so I don't know what he used but I suspect it was GL5 as the car had Jiffy Lube stickers.  I would like to know if a synthetic GL5 is superior to a petroleum GL4.
R. Smits, #2426
23 Cad 7P Touring
32 Cad 5P Coupe
38 Cad 90 Series
41 Cad 63 Series
58 Cad Eldo Barritz
The average man can take care of one Woman and two Cadillacs, Al Edmond AACA Past President

Offline TJ Hopland

  • Posts: 10188
Re: Gl4 vs GL1 gear lube
« Reply #3 on: August 30, 2017, 08:23:59 PM »
I went through this last year working on a friends car and what I came up with was GL4 is a good replacement for GL1.   Its got some higher tech stuff in it that helps with wear but not enough to cause issues with 'yellow metals' so its really an upgrade.   GL5 does have higher levels of stuff in it that maybe could cause issues with those metals but even there there seems to be some debate. 

You can still get GL1 but you have to go to a more rural area that has old farm and heavy equipment around and you may have to buy at least a 5 gallon bucket of it.    Napa has it  in 5 gallon pail NHF 65205.     They also have Staylube GL4 in I think gallons but I don't have the part number handy.   Around my area its in stock out on the floor.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Offline robert G. smits

  • Cad58y CLC 2426
  • Posts: 179
  • Name: Robert Smits
Re: Gl4 vs GL1 gear lube
« Reply #4 on: August 31, 2017, 10:44:52 AM »
Thanks to all who replied.  I will stay with GL4  until after the Glidden Tour and probably go synthetic when I do my yearly maintaince this winter.  Bob Smits #2426
R. Smits, #2426
23 Cad 7P Touring
32 Cad 5P Coupe
38 Cad 90 Series
41 Cad 63 Series
58 Cad Eldo Barritz
The average man can take care of one Woman and two Cadillacs, Al Edmond AACA Past President

 

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