strange goings on with the gearbox oil level!!

[bigdaddycain]

I was a bit worried then, I thought that a few of you guys were using the misses as a chock for the front wheels.

Nah, she's too small and squidgy

Hoggman? See dolly1's above post....Spot on!

[Dolly1]

Hi BDC,Thanks

[Aethelric]

I'm now showing my very extensive ignorance of auto gearboxes. But, after doing all these checks with engine running etc. is it not possible to "recalibrate" the dipstick to take a measurement cold and in P with the engine off? I'm sure this won't work as its too obvious, but why? What's happening in there?

Dave

[missfixit70]

I thought exactly the same Aethelric, never got around to asking the question, Glad i'm not the only one thinking a bit differently

[Dolly1]

Hi Kirsty
The question is. "Can i have a new dipstick please.This one will not reach the oil "

[dandywarhol]

I'm now showing my very extensive ignorance of auto gearboxes. But, after doing all these checks with engine running etc. is it not possible to "recalibrate" the dipstick to take a measurement cold and in P with the engine off? I'm sure this won't work as its too obvious, but why? What's happening in there?

Dave

Fair point..............don't have an answer to it.
The level is checked with the engine running because the torque convertor takes some of the oil from the gearbox sump - the reason for using "D" is to eliminate splash on the dipstick that can happen when idling at higher revs in "P", which can givw a false reading.

[scanner]

I'm now showing my very extensive ignorance of auto gearboxes. But, after doing all these checks with engine running etc. is it not possible to "recalibrate" the dipstick to take a measurement cold and in P with the engine off? I'm sure this won't work as its too obvious, but why? What's happening in there?

Dave

Fair point..............don't have an answer to it.
The level is checked with the engine running because the torque convertor takes some of the oil from the gearbox sump - the reason for using "D" is to eliminate splash on the dipstick that can happen when idling at higher revs in "P", which can givw a false reading.

I think it is also to make sure that all the valves and chambers that have to be full of oil for it to work are full and the gearbox is in running condition.

Different gearboxes with different amounts of wear could have some valves and chambers full another could have them all full and yet another could have them have them all empty.
Checking the gearbox oil level in the condition it is in when working eliminates all the variables.

An auto box (as I understand it) is not like a manual gearbox or an engine where it can be fairly well guaranteed that all the oil will drain to the bottom when cold but it can be pretty much guaranteed that when it's running in D all the oily bits are full and what is left is what needs to be measured.

Engines and manual boxes are half full, but auto boxes are half empty.

That's my theory.

[bigdaddycain]

I'd be inclined to go along with that...

[dandywarhol]

The valve block (which controls the gear selection amongst other functions) is submerged in fluid whether the engine is running or not, so all it's chambers are already full and primed.
The torque convertor drives the gearbox oil pump and the pump supplies the convertor with oil too, so that's why the level is checked running. The amount of wear is negligable in auto box clutches to the level won't alter significantly whether new or at the end of it's life.

Most vehicle manuals advise to check the level in "P" but as I said earlier, there's less splash in "D" so it's more accurate. Manufacturers probably don't recommend checking in "D" incase someones vehicle sets off by itself

[scanner]

If that is the case then there is no reason not to get a shorter dipstick and check the level cold.

[bigdaddycain]

Manufacturers probably don't recommend checking in "D" incase someones vehicle sets off by itself

Yep, thats exactly what the auto gearbox fella said...manufacturers would rather have owners read the level wrong, than chance a runaway vehicle,with a claim on the manufacturer for badly worded instructions in the manual.

Play it safe... tell em to check the level in park (the manufacturers mindset)

(golden wonder had to pay out millions in compensation to some fella in the states,cos he instantly started to eat his pot noodle,without waiting for it to cool slightly...it didn't say allow the product to cool before consumption on the tub, he got stuck in straight away,resulting in scalding to the throat...it's cos of plebs like that the instructions have to be very specific for the numpties!)

[Aethelric]

If that is the case then there is no reason not to get a shorter dipstick and check the level cold.

Thats how I read it too But it seems bizarre to have to heat up the engine, have it running (preferably in D) when it could be done cold (or even hot) with a stopped engine. Oh well - another thing to test.

[hogggman]

hi all,
thanks to `dolly`for the very specific tips on how to accurately check the gearbox oil level.i did it that way,and found the level to be spot on.at least that`s eliminated a possible cause of my rattle.
thanks again
jamie

[Dolly1]

Hi Jamie,
My pleasure.One less thing to worry about.Enjoy your Bongo.Got a name yet ????