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Race transmission breather - S/B 727
Posted: Sat Jan 15, 11 8:45 pm
by Jon Connolly
Am intending on running a small vent line from my transmission to allow it to " puke " up the tube instead of on the track.
Was planning on putting a catch can at a higher height than the trans vent outlet and putting a loop on the pipe just before going into the catch can.
My theory is this will act like a wet trap letting air out while letting fluid drain back down the tube into the transmission after a run so that the level always starts off correct
Anyone ???

Posted: Sat Jan 15, 11 8:59 pm
by Cannonball
some of the older gearboxes from late sixties early seventies had a breather high up on the trans like yours and it also had a little T off on the very top off the dipstick tube the pipe of the breather went up in the air high on the bulkhead and U turned back down on to the connection off the dip tube, and worked fine,
worth trying jon.
i just know that the 727 can breath heavy if really hot/pressured we useually put in to a jaz type catch can high on the bulkhead and check pretty regular
Posted: Sat Jan 15, 11 9:00 pm
by Jon Connolly
What provision do you make for letting the fluid return ?
or do you just manually top it up ??
Posted: Sat Jan 15, 11 9:21 pm
by Cannonball
Jon Connolly wrote:What provision do you make for letting the fluid return ?
or do you just manually top it up ??
drain jaz catch can and reuse if clean or top up through tube with fresh. set level on low mark running in neautral it will come higher on the stick after a pass,
Posted: Sun Jan 16, 11 8:33 pm
by Blue
What you can do is plug the vent in the front pump. Tap a new vent into the back of the transmission and run a line forward up the transmission tunnel into the bottom of a vented catch can high up on the firewall. That should allow any fluid that has puked out to gravity feed back into the transmission.
Posted: Sun Jan 16, 11 8:41 pm
by andyrob
Jon,on my red roadrunner which used to be bad for puking until duncan moved the breather, I removed dipstick & had breather pipe pushed in the hole (but loosly so good breath)
Had no trouble for yrs like this
Posted: Sun Jan 16, 11 9:13 pm
by TrevD
this is interesting, having never run a race trans i wasnt aware of this problem. where do they loose fluid from? top of filler tube????
Posted: Sun Jan 16, 11 9:24 pm
by Cannonball
Blue wrote:What you can do is plug the vent in the front pump. Tap a new vent into the back of the transmission and run a line forward up the transmission tunnel into the bottom of a vented catch can high up on the firewall. That should allow any fluid that has puked out to gravity feed back into the transmission.
that is what jon has had done blue,
Posted: Sun Jan 16, 11 9:26 pm
by Cannonball
TrevD wrote:this is interesting, having never run a race trans i wasnt aware of this problem. where do they loose fluid from? top of filler tube????
they puke out of a vent that is high in the pump body, the fluid then comes out the bellhsg and you can think your pump seal is blown or worse spray oil under your rear tires,

Posted: Sun Jan 16, 11 9:43 pm
by TrevD
ok so looks like i need to talk to one of you guys to plug this and run a vent on the dart
Posted: Sun Jan 16, 11 11:50 pm
by Cannonball
TrevD wrote:ok so looks like i need to talk to one of you guys to plug this and run a vent on the dart
would be wise and blue is da man down your end,
Posted: Thu Jan 20, 11 4:10 pm
by Anonymous
The trans in my Volare had a Mega Puke in Kingston (not Jamaica) straight up the filler tube, then it caught light after spraying all over da Fanimold!
Guess what, I was no where near da Pod, actually was on the way there LOL!
Bac.