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gear oil....

i just replaced all the seals in my 4 speed and was wondering if there was any gear oil that stood out as better than the rest....i.e. red line??? they have one that is MTL or something like that claiming smoother shifting and longer syncro life. i did notice it is synthetic and had a statement about not using it in a rwd differential. any comments???
 

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some rwd posi diff cannot use synthetic gear oil particularly the clutch type becuse it can ruin the clutch material but for your trans a synthetic should be fine
 

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RedLine Synthetic

Tranny use MT-90

Rear End use 75W90


Make sure you use new seals, because if it leaks a little now it will leak more with synthetic. And, at $8.00 a quart, it becomes an expensive leak.

Paul
 

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With new seals and new synthetic oils, there should be no leakage is the sealing surfaces are good and create a sealing surface with the new seals. The problem with old leaking seals is the new synthetic lubricants are so symetrical in their molecular structure and they have real good detergents in them, they will clean away to old sludge and flow right through the old leak and make it bigger as they go out on the ground. A general rule of thumb is do not use synthetics on items that have old seals, even if they do not leak. Eventually they will leak with synthetic lubes after a short time, probably within 6 months. Whereas if you did not use a synthetic it will not leak until normal wear and tear at the rotating surfaces causes leaks. JMTCW.

Ron
 
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