Auto transmission question

[cranetruck]

To be on the safe side, I thought I'd ask...
Drained the automatic transmission yesterday (xm757 Allison), replaced the filter element and refilled with the same amount of fluid, 5 gallons.

My question relates to the "Safe to start" level, before draining, the level was right on the mark, but after refilling it ended up above the mark by about an inch.

I understand that the filter housing and all the passages within the transmission may not be filled, so is it safe to start or should I drain some and fill more after running it?
It's been 18 hours since refilling.

Thanks

 

[Rattlehead]

I'd say if that is the amount you took out of it and the level was fine, go ahead and start it. A risk of overfilling an engine or trans is oil aeration. But if you are just idling, you are not risking burning up of any clutches due to entrained air/reduced clutch apply pressure. Also, if it is overfilled and you work the trans hard, then you risk puking trans fluid out the dipstick tube and possibly onto a hot exhaust. But idling you are fine.

For an auto trans, I usually fill up to the top of the level, then idle it and monitor, add as necessary. The trans will be underfilled at first start, but you aren't applying clutches and putting them under load. When you get the level around the bottom of the safe level while idling, then take it for a spin around the block and make sure the trans is fully up to temp before rechecking/topping off, as the level will rise on the indicator as the temp warms up.

 

[pa.rich]

I feel funny giving you advice Bjorn, could you drain a little out, run it for a few minutes and then refill as needed? Or is it difficult to get at? If its not a huge filter there maybe too much in there? The filter will take a little, but if it is a huge tranny and it says over filled, you might want to remove some fluid so it is on the line, run it and recheck the stick. Just my humble opinion. BTW, the truck looks great. Oh and is there an oil cooler that would take some fluid after running? Regards, Rich.

 

[cranetruck]

Re: RE: Auto transmission question

I feel funny giving you advice Bjorn,......

Yes, you should, I know everything......yeah right.
Anyhow, I asked my friendly neighborhood transmission expert and was told that it is normal. "Just start it and run it through th gears and the level will drop".

Did so, and it's back to normal.

You are about right on target Rattlehead.

Thanks guys.

 

[pa.rich]

RE: Re: RE: Auto transmission question

You mean you dont know everything? You just burst my balloon! Glad the tranny is alright.