Auto fludid Level

[ng4xjs]

I admit I'm a little flummoxed. I'm trying to get the correct amount of fluid into my auto-gearbox. I though it might be a good thing as I'm trying to find a smoother change from first to second. This was my approach. I took the car or a good 30 minute run and then checked the level when running. It was way down and so I topped it up with about 250mm fluid. Repeated the same the next day and ended up with a further 250mm. After a further run, better change and fluid within the "hot" band on the dip stick.

I checked the level the next day and fluid level at cold, engine not running above the hot level. Checked after a run and back to about correct.I'm guessing that when the engine is running and hot that the level will reduce from a higher reading cold level. Just seems at cold that a fair way up the dip stick. Does this all sound about right. Thoughts greatly appreciated.

Many thanks
Nick

[steve_m]

That sounds about right Nick; just make sure that you run it through all the gears (including reverse) when the engine is running before you measure it.

[RichardSEL]

Your changing level between hot and cold engine temps is correct.
Some older boxes (BW8 comes to mind) won't even select a gear with old fluid unless it's hot

When fluid and filter change is done -- about every 60-80,000 miles recommended BTW -- the final fluid level is usually done at a specific temperature. This needs to be an accurate measurement on smaller present day auto-boxes

[ng4xjs]

Thank you both

Nick

[ng4xjs]

I'm still enduring harsh changes between 1st and 2nd and before I consider other mechanical possibilities I would like to change the fluid. I did this about three years ago and I guess that because only about a third drains out there really was no big difference. The fluid in mine is not cherry red but a light brown and I wonder whether this is not assisting a smooth change. Have others experienced this? Also any thoughts on having a flush and refill rather than by the conventional filter and one third fill?
Happy days
Nick

[davidr]

Once you've drained and refilled a few times you will have changed a very high proportion of your transmission fluid. I would be more inclined to do that a few times than pay someone to flush the system.
I recall a thread on here somewhere that discussed this approach.

[Tintin]

FWIW I drain and refill my trans fluid every time I change the engine oil - that way it dilutes the old fluid regularly.

The WSM procedure for checking level is:- fluid must be at normal operating temp (15 mile drive minimum); park and idle on level ground; move selector through all positions to ensure system is fully primed; return to "P" and leave idling; remove dipstick and wipe; replace stick and immediately withdraw again; take reading on stick. If you idle for too long you will need to re-prime by moving the selector again.

The COLD side of the stick gives an approximation only (before starting a fully cold engine).

Good luck.

Robbie

[poprivet]

Nick, has the gearbox electrical connector been checked for corrosion and cleaned with a quality contact cleaner spray, I know they are prone to cause faults.

I wouldn't have thought fluid level would result in poor quality changes, on the early mechanical ZF boxes it is the governor that causes the delayed or harsh 1st to 2nd change, your later box uses electrical signals from sensors in the box to do the same.

[ng4xjs]

Thanks Pop - I'd not thought of that. I'll have a look see.
Nick

[ng4xjs]

A supplementary. Has anyone sucked fluid out through the dip stick tube in an attempt to get it cleaner. Indeed can it be done?

Nick

[steve_m]

I just used one of these to empty the sump on my boat engine through the dipstick tube.
It worked really well; nothing came out of the sump when I took the plug out.

https://www.ebay.co.uk/itm/BRASS-HAND-S ... m570.l1313

[ng4xjs]

Hi Steve - My suction pump is not as well engineered as the one you have come accross. I sucked out 0.75L through the dipstick tube and replaced it with nice clean Dexron 3. There is quite an improvement in smoothness. I'll do it a few more times and see if I can improve the quality of the colour (and performance) of my fluid. A full change a couple o years ago still left a light brown colour.

Has any one else used the dip stick tube to remove fluid?

Nick

[Tintin]

Hi Nick

You should be able to get about 3 litres out (of a total capacity of about 5 litres) by draining from the sump. Why don't you do that rather than take small quantities out with a syringe?

Robbie

[ng4xjs]

Robbie - You are right of course, I'm being lazy and know it

Nick