Transmission flush help

M

mustang8

Senior Member
Guys my 48 f1 has a 3 sp manual in it. What is the process of changing out the fluid on this thing? Does it have a drain plug or do I have a pan to pull off or? Also my guess is this takes grease not MTF fluid? Thanks guys. Im a total rookie on these years vehicles.
 
The first recommendation I will make is to buy a mechanics creeper and take a look at what you are imagining. Your transmission uses gear oil and not grease. If the transmission contains any yellow metals it is best to find a gear oil specified GL-1 as extreame pressure additives can harm brass and such.
 
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I think it be same as my 39 -****** gl1 best next gl4 84-140 or st 140 or sae 90 for cold weather takes 2.75 pints capacity 44 oz - i found at napa - u should have plug to drain and one up higher to fill on pass side
 
So GL-1 is my best option? Looks like GL-4 is the really common type of gear lube, but I want to make sure I put the right stuff in.
 
Is it best to just drain then add the 44oz back in or should a person flush out the system through the fill hole then re fill with the correct amount. If its like any other fluid on this truck other than the motor im guessing it has NEVER been changed. The rear end fluid was junk.
 
GL-1 is what I use in my 8N, I get it at Tractor Supply or NAPA, you can also get it at your local Ford/New Holland dealer.
 

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GL-1 and GL-3 doesnt have any EP additives that can harm the redmetals.

A modern good engine oil will do the job as good as a GL-1(i will get beaten for this...)

Flushing the gearbox...you have plenty of room for slush in it just change the oil and run it.
 
flatheadmurre said:
GL-1 and GL-3 doesnt have any EP additives that can harm the redmetals.

A modern good engine oil will do the job as good as a GL-1(i will get beaten for this...)

Flushing the gearbox...you have plenty of room for slush in it just change the oil and run it.
Click to expand...

Believe GL-3 does have EP additives, just at a lower level than GL-4.

API GL-1​
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Straight mineral oil​
API GL-2​
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Mild EP for worm gears​
API GL-3​
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Mild EP for spur and spiral bevel gears in axles and transmissions​
API GL-4​
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Medium EP, MIL-L-2105 quality, moderate severity hypoid gears, manual​

transmissions​
API GL-5​
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High EP, MIL-L-2105D quality, all hypoid axles, some manual transmissions​
API GL-6​
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Extra high EP, now obsolete​

 
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GL-2 and GL-3 additives doesnt harm redmetal bearings when you go to the higher hypoid type oils you have issues with that.

Think i got it right...
 
Thought it was discussed at length on another thread, that the Sta-Lube brand GL-4 140w or 90-140 for colder climates, was the gear oil to use?
 
GL-4 might affect you synchro pieces made out of redmetal how fast and how bad is the question.
I know from running planetary drives that is non roller bearing units GL-4 isnt a good choice the redmetal bearings go bad.
Most tractor gearboxes that share oil with hydraulics run 10/30 and they arent low load units ;)
An as thick as possible oil isnt the best choice always.
 
Had a rep from Justice Brothers come in to our municipal shop and show us a bunch of his products. After changing out the fluids last year on the truck and very minimal usage ive noticed that its about impossible to not grind the gears while shifting so im going to try some one of their additives to see if I can get the ****** cleaned up a bit more. Anyone ever try anything to help or do you think the ****** is just shot? My plan is to do the t5 ****** swap this year but id like to drive it a bit until I get all the parts needed for the swap.
 
No I did not. How difficult is that? If it involves pulling the ****** I wont mess with it either, since id like to do the ****** swap.
 
I'm not sure what year car you have but my 39 is fairly easy to do.

Please add car details. Hopefully someone on here can post the instructions.
 
... another oil thread. This time transmission oil.

Curious, but what does Mac Van Pelt's transmission book say about what oil to use in a flathead transmission? GL1? GL2? GL3? GL4? GL5?

What gear oil does he sell on his website and evidently suggest using?
 
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