Transmission Fluid Leak

#1
I moved the car out of the shed today only to find a large pool of automatic transmission fluid on the floor. I had the inhibitor switch replaced recently and am wondering if the two things are connected.

I tried starting the car to dip the ATF but will not turn over - inhibitor switch again?
 

harveyp6

Well-Known Member
#3
RonnieRover said:
I moved the car out of the shed today only to find a large pool of automatic transmission fluid on the floor. I had the inhibitor switch replaced recently and am wondering if the two things are connected.
How long had the car been left standing without running?

RonnieRover said:
I tried starting the car to dip the ATF but will not turn over - inhibitor switch again?
It could be the inhibitor switch was incorrectly adjusted when it was fitted if it's a BW35. BW65 switches don't tend to suffer with that problem. Try starting in both "P" & "N", and if that doesn't work, try wiggling the gearlever a touch in both those positions while holding the key in the "start" position.
 
#4
Hi Harvey
The car has been standing for 3 weeks. I had the work done a week before that and the car was starting, running and driving perfectly after the work was done and before I parked it up.

Will try wiggling the lever while starting to see if that gets it going so I can at least dip the ATF
Conor
 

harveyp6

Well-Known Member
#5
RonnieRover said:
The car has been standing for 3 weeks.
In that case it may be that the converter has drained back into the gearbox itself, artificially raising the fluid level, and causing some fluid to leak out. I wouldn't do anything until you've had it running again, although to prove the point (or not) you could dip it as it is now, before it's run again, to see if the level is way above where it should be.
 
#6
Harvey,
I dipped it and you are correct, the level was way too high. Could I be a pain and ask you to explain what is going on here? What would cause this as a one off (if it is one off?)
Conor
 

harveyp6

Well-Known Member
#7
RonnieRover said:
Harvey,
I dipped it and you are correct, the level was way too high. Could I be a pain and ask you to explain what is going on here? What would cause this as a one off (if it is one off?)
Conor

The weight of the fluid in the top half of the converter forces it back past the check valve and into the gearbox itself, raising the level. The moment the engine starts again it refills the converter and the level goes back to normal. The leaks arise because the fluid level gets far higher than it should be. The check valves are supposed to prevent the drain back, but most of the time they don't work. The only way to prevent it is to start the car up every few days.
 
#9
Harvey,
The oil is dripping down the threads of the inhibitor switch. I've either the wrong switch, it was not fitted correctly, or it's faulty. Once I can get my hands on the correct transmission fluid, I'm going to top it up and get it over to the guy who did the work for me. (Provided I don't top it up and it doesn't come straight back out again !)
I'm wondering if I have a 35 or 65 gearbox - it's a 1972 model ?
Conor
 
#10
I could be totally wrong but I think a '72 would have had a 35 which doesn't mean to say it couldn't have had a 65 fitted in the interim. A 65 will have a cable-type connection to the gearlever, a 35 has rods. And the filler tubes are on opposite sides of the car. 65 nearside IIRC.

Once again, Harvey will be along to shoot me down in flames.
 

harveyp6

Well-Known Member
#11
The Rovering Member said:
I could be totally wrong but I think a '72 would have had a 35 which doesn't mean to say it couldn't have had a 65 fitted in the interim. A 65 will have a cable-type connection to the gearlever, a 35 has rods. And the filler tubes are on opposite sides of the car. 65 nearside IIRC.

Once again, Harvey will be along to shoot me down in flames.
Mmmm......Much as I'd love to shoot you down in flames....... (But I feel sure you must have lifted all the above from one of my previous postings..... :lol: )
 

harveyp6

Well-Known Member
#12
RonnieRover said:
Harvey,
The oil is dripping down the threads of the inhibitor switch. I've either the wrong switch, it was not fitted correctly, or it's faulty.
If the switch is threaded directly into the casing, it's a BW35, there are different BW35 switches, but they're all interchangeable. There should be a sealing washer behind it, and a small amount of PTFE tape on the threads helps as well.

The level should never be that high, so in normal use, with a correct level, you might find it doesn't leak.
 
#13
The Rovering Member said:
I could be totally wrong but I think a '72 would have had a 35 which doesn't mean to say it couldn't have had a 65 fitted in the interim. A 65 will have a cable-type connection to the gearlever, a 35 has rods. And the filler tubes are on opposite sides of the car. 65 nearside IIRC.

Once again, Harvey will be along to shoot me down in flames.
It's a 35 then - thank you

harveyp6 said:
If the switch is threaded directly into the casing, it's a BW35, there are different BW35 switches, but they're all interchangeable. There should be a sealing washer behind it, and a small amount of PTFE tape on the threads helps as well.

The level should never be that high, so in normal use, with a correct level, you might find it doesn't leak.
Yes it's threaded directly into the casing. Will reinstall with the tape and check the sealing washer

Thanks for your help
 
#15
Looks like there was an issue with the inhibitor switch. It had somehow managed to split along the threads (maybe as it was being fitted) so quite an easy fix this time around with a replacement unit.

Thanks for your help on this one .....
 
#16
BW35 Trans Fluid Leak/noisy reverse gear

In that case it may be that the converter has drained back into the gearbox itself, artificially raising the fluid level, and causing some fluid to leak out.

Hello P6 friends,

- my BW35 is still losing much oil (Bw35 was rebuild in circa 2010 by Rover Club Austria) and again in 2013 (reverse gear did not work anymore),
but it seems, they did not do a good job, because it is still losing much oil. my workshop said, the oil is not draining back from converter. (?)

- since a few weeks, the reverse gear of my BW35 sounds very rough and loud.
- I must fill up auto trans fluid now every 80-100 km, because the trans starts to slip.

OIL: what is the secret, to solve the problems? is it just a seal? (I am always using castrol TQF fluid)
NOISE: I am worry about this noise.

do you have any advice? I am scary to have again an auo trans box damage. :shock:
kind regards, richard
 

Attachments

harveyp6

Well-Known Member
#17
Re: BW35 Trans Fluid Leak/noisy reverse gear

sagegreen said:
my workshop said, the oil is not draining back from converter. (?)
How do they know that for certain? And if that is the case it can only mean that it's leaking externally with the fluid at the normal level, which shouldn't be the case so soon after a rebuild.

sagegreen said:
- since a few weeks, the reverse gear of my BW35 sounds very rough and loud.
If the noise is only apparent in REVERSE then it could be the gearset. (But that's obviously a guess without the benefit of actually hearing it).




sagegreen said:
- I must fill up auto trans fluid now every 80-100 km, because the trans starts to slip.
If you're going from the correct level down to the point where the transmission slips because of low fluid in 80-100km that needs looking at as a matter of urgency.

sagegreen said:
OIL: what is the secret, to solve the problems? is it just a seal? (I am always using castrol TQF fluid)
External leaks are gaskets and seals, but if the converter is draining back then the only success I've had fixing that is fitting a check valve in the cooler return line, and I've only found one of the check valves.


sagegreen said:
NOISE: I am worry about this noise.
So am I.

sagegreen said:
do you have any advice? I am scary to have again an auo trans box damage. :shock:
Loud noises and running with low fluid level will cause damage sooner or later, and most likely sooner at the rate you're losing fluid.
 
#18
Re: BW35 Trans Fluid Leak/noisy reverse gear

harveyp6 said:
sagegreen said:
my workshop said, the oil is not draining back from converter. (?)
And if that is the case it can only mean that it's leaking externally with the fluid at the normal level, which shouldn't be the case so soon after a rebuild.

sagegreen said:
- since a few weeks, the reverse gear of my BW35 sounds very rough and loud.
If the noise is only apparent in REVERSE then it could be the gearset. (But that's obviously a guess without the benefit of actually hearing it).

sagegreen said:
- I must fill up auto trans fluid now every 80-100 km, because the trans starts to slip.
If you're going from the correct level down to the point where the transmission slips because of low fluid in 80-100km that needs looking at as a matter of urgency.

Hi dear Harvey,

I am glad, that you response,
yes, the auto trans was starting to leak (a little bit) short after rebuild. during the last time, its becoming more and more.

Reverse: example: if I start the car (standing over night), put the reverse gear in, it sounds rough and by trying to drive in reverse gear backwards, the transmission slips the first 1- 2 seconds.


Infomation: ist a NADA car but have the dipstick/filler tube inside the engine area like the S1 P6B‘s

during test drive with correct fluid level (as described in original workshop manual from 1969) the transmission start to slip a little bit -
after circa 1,5 hours of driving (during D drive). I parked the car, checked the fluid level and the dip stick was dry and clean, some little smoke was coming out oft he dip stick/filler tube.

after filling up the fluid level again, I could drive home again without any problems. so, there is now a massiv oil leak, because it‘s also losing some oil when the engine is off.

URGENCY: yes, thats my problem. there is no workshop, mechanic, garage which is able to repair my BW35 here in austria. do you have any idea/contacts/references to a solid workshop in the austrian/german regions for a perfect, correct rebuild of my BW35?

I have a spare BW35 (from a S2) in my basement. I bought it as a "before running/working" transmission 2 years ago.
How is it possible, to test/check this Auto box before putting into the car? Is there the need, to rebuild an "auto box" which was not running for 3-4 years?

thank you for your advices.
kind regards, richard
 

colnerov

Well-Known Member
#19
Hi, see my reply in your PAS thread about the rad cooler hoses leaking.

I would not press your spare box into service without rebuilding it first, you may get away with
a seal kit if your really lucky. When they are not used the seals dry out and won't ...well seal.
Plus I would suggest you do this sooner rather than later before your g/box in the car lets go.

Colin
 
#20
colnerov said:
I would not press your spare box into service without rebuilding it first, you may get away with
a seal kit if your really lucky. When they are not used the seals dry out and won't ...well seal.
Plus I would suggest you do this sooner rather than later before your g/box in the car lets go.

Colin
hi colin, thanks for info. yes, this was also my doubt, that my spare-trans-box must be first rebuild. it is good to hear your confirmation. well, at the moment I can / i do not drive the car, I will try to fix the massive PAS oil leak and after this its winter time here. so, the car will be in my garage until next spring without driving. in spring/summer 2016 I will send the box to U.K. for a rebuild.

kind regards, richard
 
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