'90 740 tranny fluid level and...

[e777]

I just renewed my tranny fluid and when I checked the level it seemed too high (I had added the recommended 4 liters). So I started the motor and let it run for about 15 minutes thinking that a more accurate reading would be possible after the fluid had circulated through the cooler, etc. With the engine running i pulled out the dipstick and found it bone dry. This was repeated a few times over a period of five minutes-each time dry, as if there were no fluid at all. I shut off the motor and within minutes the "hot" reading on the dipstick was just at the right level.

So, my question: When measuring the fluid hot, must the engine be off? This seems to be the case, but I just wanted to make sure. I am used to checking the fluid with the engine running on old Chevy trucks,...

Also, I pulled out the oil dipstick with the motor running and a small amount of smoke kept wafting out. What does that mean?! Can't be good, I suppose.

Cheers,

Eric
1990 740 gl SW 267K

[billofdurham]

This is the Volvo instruction:

740 auto box fluid check.pdf

(82.25 KiB) Downloaded 75 times

I always do this when the negine is at working temperature.

The box on the 740 takes 7.9 US quarts or 7.5 litres. Depending on how much you removed during the service you may not have added enough. I know Haynes says 4 litres for a drain and refill but I think that is after removing the bare minimum of fluid.

With regards to the smoke from the dipstick tube - how long is it since the crankcase ventilation system was cleaned? A choked flame trap will cause back pressure and the oil will come out in a fine mist, not necessarily smoke, from any opening it can.

Bill.

[e777]

Thanks, Bill. I followed the instructions to check the fluid when hot, with the car idling, and the dipstick was still dry (which, again, strikes me as very odd given the cold reading was well above the maximum mark on the dipstick). So I decided that I should add some fluid. This seemed to do the trick.
Cheers,

Eric

[billofdurham]

Engine oil level should always be read cold and with the engine off to find the true level in the sump. In contrast transmission fluid level should be done with the engine running at normal temperature to make sure that all the hydraulic chambers in the transmission are filled with oil and the fluid is circulating normally. This should ensure that your fluid–level reading is accurate. This is why the cold reading was high.

Bill.