Click on image for the lowdown. 
====
| | | Forums66 Topics128,090 Posts1,056,022 Members48,430 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Jul 2008 Posts: 181 'Bolter | | 'Bolter Joined: Jul 2008 Posts: 181 | I know it has been questioned and answered before but if I may; what today's gear oil can be safely used in a 52 1/2 ton with a 3 speed transmission. Having trouble finding a mineral based oil. GL5 states it has anti-corrossive properties for bronze parts. Is it safe to use? Thanks for any thoughts. | | | | | Joined: Feb 2004 Posts: 29,787 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,787 | Tractor Supply Co.- - - -use Ford-specification 90 weight transmission lube. It's identical to the lube GM specified when the transmissions were new. Some of the more modern lubes are too slippery, and they don't let the synchronizers get a good grip on the gears to match speed properly.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Jul 2008 Posts: 181 'Bolter | | 'Bolter Joined: Jul 2008 Posts: 181 | TSC shelves were near empty of gear oil, no Ford spec. RK had GL5 only. Will try TSC on line. Thanks. | | | | | Joined: Aug 2018 Posts: 351 'Bolter | | 'Bolter Joined: Aug 2018 Posts: 351 | Use the GL5 hypoid lubricant in the rear axle assembly. The GL5 lubricants are not required for the transmissions, and typically are too slippery for proper synchronizer action, as Jerry stated. My preference - in part based on what I keep in my shop to service several older BMWs - is Red Line Oil MT-90 for these older transmissions. The MT-90 is GL4-rated - sufficient for transmissions - has the correct viscosity, correct slipperiness for synchronizers - which most of the GL5 lubricants do not - and works well in a variety of transmissions since it's yellow-metal friendly. The Red Line Oil MTL (too light in viscosity for the 'Bolts) has quieted more than one noisy or "grunchy" BMW/Getrag transmission. The MT-90 product uses the same technology as MTL in a bit higher viscosity. For an interesting read, here is a White-paper from Red Line. There are other brand products that are similar - look for one that is very specifically noted for transmission service if you decide on something besides the Red Line Oil product, or Ford-spec mineral oil. Hope this helps. Doug
Last edited by drdoug; 08/12/2021 1:04 AM.
| | | | | Joined: Feb 2019 Posts: 4,478 AD Addict & Tinkerer | | AD Addict & Tinkerer Joined: Feb 2019 Posts: 4,478 | I ran into the same issue. I went to another TSC location to find it. Here’s the link on line. It’s hard to find. https://www.tractorsupply.com/tsc/p...90-transmission-fluid-2-gal?cm_vc=-10005
Last edited by Phak1; 08/12/2021 12:47 PM.
Phil Moderator, The Engine Shop, Interiors and Project Journals1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc BrakesProject JournalsStovebolt Gallery Forum | | | | | Joined: Jul 2008 Posts: 181 'Bolter | | 'Bolter Joined: Jul 2008 Posts: 181 | Thanks everyone. Found the ford 90wt at another store TSC store. | | | | | Joined: Feb 2019 Posts: 4,478 AD Addict & Tinkerer | | AD Addict & Tinkerer Joined: Feb 2019 Posts: 4,478 | Thanks everyone. Found the ford 90wt at another store TSC store. 
Phil Moderator, The Engine Shop, Interiors and Project Journals1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc BrakesProject JournalsStovebolt Gallery Forum | | | | | Joined: Jan 2016 Posts: 1,101 'Bolter | | 'Bolter Joined: Jan 2016 Posts: 1,101 | I just tried the link and for my local TSC company it says Not Available for Pickup in Store, Standard Delivery or Same Day Delivery. It does show in a couple other stores that are not too far from me. I have been putting off getting some. I guess I better keep my eyes open and grab some when I can.
I know where the fill hole is and my understanding is to drain the system I must drop the pan. Is there any type of filter I need to worry about.
Last edited by dgrinnan; 08/13/2021 11:58 AM.
| | | | | Joined: Feb 2019 Posts: 4,478 AD Addict & Tinkerer | | AD Addict & Tinkerer Joined: Feb 2019 Posts: 4,478 | If you have a SM-318 three speed or SM-420 four speed, the drain is a pipe plug under the tranny. There is no filter.
Phil Moderator, The Engine Shop, Interiors and Project Journals1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc BrakesProject JournalsStovebolt Gallery Forum | | | | | Joined: Jul 2008 Posts: 181 'Bolter | | 'Bolter Joined: Jul 2008 Posts: 181 | Phak1 has it right. Draining is the easy part, refilling is the difficult part. I am soon changing the floor mat and insulation in mine and while I have it out will remove the transmission cover plate, then drain the fluid and refill much easier from the top side. | | | | | Joined: Oct 2008 Posts: 308 'Bolter | | 'Bolter Joined: Oct 2008 Posts: 308 | Synchronizers? What are they?
Ha ha. | | |
|
|
