Overfilling transmissions?
- Thread starter Dr_No
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How much are you adding?
Some trannies are more touchy about levels. I know some work fine up to about a quart over. I would avoid more than half quart over full.
I assume there is something already wrong with the tranny? If it works fine I wouldnt add anything except maybe ARX if you think it needs it.
Some trannies are more touchy about levels. I know some work fine up to about a quart over. I would avoid more than half quart over full.
I assume there is something already wrong with the tranny? If it works fine I wouldnt add anything except maybe ARX if you think it needs it.
What additive and why? What transmission, current condition, maintenance history, issues?
You northern location will tolerate mild overfilling since average ATF operating temperature is lower.
<pint shouldn't be an issue. Just make sure you are NOT already overfilled prior to adding your additive.
You northern location will tolerate mild overfilling since average ATF operating temperature is lower.
<pint shouldn't be an issue. Just make sure you are NOT already overfilled prior to adding your additive.
Don't add snake oil to your transmission unless it's lower than the fill line and thats all you have.
I think the fill line usually says "Max" for a reason. They have calculated the highest they want warm and fully expanded fluid to go. My AW 343 is very sensitive to overfilling.
Draining just a little fluid is pretty easy though. Pull the plug and have it fill into a clear quart container until you have the needed room, then replace the plug.
I think the fill line usually says "Max" for a reason. They have calculated the highest they want warm and fully expanded fluid to go. My AW 343 is very sensitive to overfilling.
Draining just a little fluid is pretty easy though. Pull the plug and have it fill into a clear quart container until you have the needed room, then replace the plug.
Never overfill a automatic transmission. It's worse than running it low on fluid.
Some MT's can benefit from the tilt 'n fill method.
Never overfill manual transmissions.
Never is a strong word. I agree with you that one should NOT randomly overfill MT's. However, there are some MT's that benefit greatly by being filled higher than the check plug. Two that come to mind are the M46 used in many RWD Volvo's (4+OD) AND M56 used in Volvo FWD. Simply tilting the car will filling, until the usual overflow, screwing the check plug adds about 1/2-3/4 qt more or so. This is no way harms the performance, longevity, causes no leaks, etc - but results in cooler running, better shifting and longer fluid and gear life.
I can't think of one reason why anyone should overfill a manual trans. Overfilling blows out the seals and the gear lube gets churned up by the gearset and it turns into a non-lubricating froth.
Well the main reason is design. Some designs, especially the M45 (which I didn't mention) was designed with the fill plug too low to allow the proper amount of lube to contact all the gears. When filled on level ground to the "proper" amount - the tranny will fail prematurely giving this tranny a well earned fragile reputation. When the "tilt and fill" method is employed gear life is quadrupled. To a lesser extent it works well on the M46 and M56 with no frothing, blown seals, etc. I'm not talking about packing it tight with lube, 1/2-3/4 quart or so AND as I have stated twice now I don't advise people to randomly overfill their MT's unless they know what they are doing.
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