Rolls-Royce and Bentley Forums banner
1 - 15 of 15 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
I've just got my '80 Shadow going after a couple of years rest-up. Fired up no problem and runs ok.
Problem is when braking, ATF shoots out of the filler tube.
Previously, I changed the radiator, and drained fluid from oil cooler. I filled it back-up but was unable to check proper level when hot.
I thought I might have overfilled it. However, when running now, oil doesn't reach bottom of dipstick.
I'm wary of adding more oil only to have it come out top of filler tube again.
Has anyone got ideas on what could cause this? I think I had a similar problem years ago.
 

·
Registered
Joined
·
3,353 Posts
What is the reading on the A/T dipstick when warmed up (driven), IN PARK AT IDLE ?
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #3 ·
I've only drove about 2miles in traffic, but transmission was warming up. The oil doesn't reach bottom of dip stick. I don't want to risk driving further with too little fluid. I don't know how much came out the top of filler, but driving along there was plenty of smoke where it hit manifold!
Handbook says, when cold top-up to 1 1/2" below max.
 

·
Registered
Joined
·
3,353 Posts
Repeat.........The only way to properly check your trans fluid is to drive a short distance. put car in Park and pull up parking brake. Next pull up A/T dipstick. It has to be in the upper end of the crosshatch.
 

·
Registered
Joined
·
4,115 Posts
I don't know what you're consulting in the Owner's Handbook, but it's not the procedure for checking the transmission fluid level.

Not just for RR, but any automatic transmission car I'm aware of that has a dipstick, you only check the transmission fluid once the transmission is completely up to normal operating temperature with the car on a level surface and idling in either Park or Neutral (with parking brake applied, of course).

Here are the pertinent pages from the Owner's Handbook:

30306


30307


30308


Dead cold, sitting in the driveway, the fluid level on the dipstick should be even higher than normal, as all of the fluid will have drained back out of much of the transmission into the sump. I'd have to go outside to check that and don't have time to do so at the moment.
 

·
Registered
Joined
·
816 Posts
The fluid in my car is correct - checked when fluid is hot, engine running in P with parking brake on. When the engine is cold the fluid is way above max level by 2 1/2 inches. What is the fluid level on your dipstick when cold? I'm asking this as I understand your concern about running the car with too little fluid in it.

If the fluid is too low it will suck air into the filter, foam up and blow out of the dip stick. - Paul Yorke.
 

·
Registered
Joined
·
4,115 Posts
Handbook says, when cold top-up to 1 1/2" below max.
It absolutely does not say that. What it says is that when cold you'd expect the fluid to be at approximately that level after the car has been running in place for 3-4 minutes. See page 97. That's to give you an idea of what you should be seeing, and if you're seeing nothing then something's off.

You only top-off a transmission that's been checked warm.

And I see Geoff has confirmed my memory as to what one generally finds in a dead cold transmission when the car's been sitting. Starting the car does start pumping transmission fluid back into the transmission immediately, hence the reason it falls to below max while cold, as the fluid will expand as it warms.
 

·
Registered
Joined
·
816 Posts
Brian - I concur. On a stone cold engine Ohgee should be getting a reading on the dipstick above max for the reason you state. If not, it would be unwise to run the car as per handbook for a precise reading.

To reiterate Paul Yorke's comment in a earlier thread " If the fluid is too low it will suck air into the filter, foam up and blow out of the dip stick. " This may be why Ohgee states "ATF shoots out of the filler tube "

Paul also mentions making sure there is no blockage, or kinks in the oil cooler lines.
 

·
Registered
Joined
·
4,115 Posts
And if the fluid level is that low, then some heavy-duty checking for leaks is necessary.

If it doesn't even show up on the transmission dipstick, and the car had been sitting in one place, there should be a pool beneath it in order for it to have gotten that low. Here's the page that shows the fluid capacity for the transmission:

30309


Most of us, of course, will never have dealt with a dry transmission, but look at the amount of fluid that it takes to fill one and how much that means remains "at rest" in various areas when the car is turned off. But even just the amounts in the sump, if you had a leak, should leave some evidence.

I guess it's possible that the fluid would only push out while the car is in motion, but I'd find that this being the only time when anything would exit and leave no trace of doing so is not probable.
 

·
Registered
Joined
·
3,353 Posts
Once your motor is off alot of fluid that was in the torque converter will flow back into the gearbox sump and will raise the level well over the top mark. Once the gearbox is warmed and driven, fluid is circulating and level established to make the various actuators working since many relay on pressure especially on a TH400.
When I rebuilt the gearbox and sent out the torque converter to be cleaned, polished and balanced on my 1980SWII it took awhile before fluid levels were established.
 

·
Registered
Joined
·
2 Posts
On Bentley Heritage site, under Technical look for Service Bulletins 1976-86. Under section T, bulletin T6 regarding loss fluid out dipstick and revised dipstick.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #12 ·
I welcome all your replies.
Perhaps I hadn't made clear the situation with my car. Due to UK tax and licencing rules I haven't been able to drive on public roads. So, transmission oil could never get to correct temp. to check properly. That was why I wanted to know a rough guide to what level on dipstick with engine running, before attempting any long journey.
The handbook I have, although not correct for car, is for cars from serial no.13754.
I agree that the oil pushing up through filler tube was because it was too low, causing a sort of frothing pressure effect.
I returned to car and after sitting for a week it wouldn't even engage in gear. The level of fluid when engine not running was well above max, but when running didn't register on dipstick.
Having added 2 litres of ATF and level when running at 1 1/2" below max, it now drives and I feel confident to drive long enough to heat up transmission and then take a correct reading..
 

·
Registered
Joined
·
3,353 Posts
Your're on the right path. Definately check on a level surface when warmed up.
 

·
Registered
1971 Bentley T
Joined
·
56 Posts
When I see the word ATF I think of something other than Dexron. I assume that Dexron has been used here - it's what the box was designed for. Or am I wrong - again?

Alan D.
 

·
Registered
Joined
·
4,115 Posts
When I see the word ATF I think of something other than Dexron. I assume that Dexron has been used here - it's what the box was designed for. Or am I wrong - again?
For that era, and for a GM derived transmission (which is what our cars have), I only think of Dexron. And Dexron-II or Dexron-III were the most likely original fluids, depending on the model year of the car. Dexron was also used for the power steering fluid as well.

If one is changing fluid today you'll likely use Dexron-V (I think, double check, as I know that "the latest generation" of Dexron is NOT backward compatible, but that up through whatever number, if it's not V, is.) Of course, Dexron-III was so widely used that you can still buy many companies' versions of Dexron-III, even though GM does not any longer support that specification officially. But the spec is very, very well known, and anyone who wishes to make ATF to the Dexron-III spec can still do so, they just can't call it Dexron-III. They have to say something like, "Equivalent to," or, "Compatible with," ahead of Dexron-III.
 
1 - 15 of 15 Posts
Top