727 losing fluid from rear vent

Posted By: J_BODY

727 losing fluid from rear vent - 02/19/14 04:02 PM

727, griner brake.... Can drive around in pit area, was on the brake for approx 8 sec in the pit area and nothing. Make a pass and there is fluid down the side of the trans and on the crossmember. Pulled the tail shaft last night and verified the hole in the "pawl hub" has been plugged. There is only one open ended sealing ring in the front groove. I haven't really been around this car full time very long, but as much as it's leaking I think my dad would have definiately noticed. I've almost got to say it wasn't doing it when the W5 engine was in it. Only other changes were I ditched the hydraulic hose trans cooler lines he was running, and changed to a 2qt heat sink type cooler at the front of the car (not the type with a filter). Trans temp is not "hot"....warmest it was all weekend was 190 on a back to back pass. Ideas welcome!

Posted By: MoParFish

Re: 727 losing fluid from rear vent - 02/19/14 04:32 PM

I was having similar issues. After plugging governor feed in park gear I also mounted a catch can up inside the right fender. I ran a hose from the vent up to the bottom of the catch can. Can is vented at top so if fluid does puke out, it will drain right back. Also moved vent fitting a little further back into top of tail housing just for easier access. So far so good. Good luck on yours.

Posted By: MR_P_BODY

Re: 727 losing fluid from rear vent - 02/19/14 05:27 PM

I dont know why yours would be puking fluid unless
its over full... I have my vent mounted in the rear
(727, TA brake front vent plugged) and never had a
drop come out... the can and hose might be the only
thing for your... I just dont know why its dripping

Posted By: Al_Alguire

Re: 727 losing fluid from rear vent - 02/19/14 05:27 PM

Run a little less fluid?? We do it in the glides all the time. About a pint low. Or a puke tank which we are required to run anyway.

Posted By: mokid

Re: 727 losing fluid from rear vent - 02/19/14 09:02 PM

Quote:

Run a little less fluid?? We do it in the glides all the time. About a pint low. Or a puke tank which we are required to run anyway.

Whats the total qts you put in using a deep pan

Posted By: Sammy

Re: 727 losing fluid from rear vent - 02/19/14 09:58 PM

Quote:

Quote:

Run a little less fluid?? We do it in the glides all the time. About a pint low. Or a puke tank which we are required to run anyway.

Whats the total qts you put in using a deep pan

Depends on the size of the converter.
Usually 8 quarts.

Posted By: mokid

Re: 727 losing fluid from rear vent - 02/20/14 12:02 AM

Quote:

Quote:

Quote:

Run a little less fluid?? We do it in the glides all the time. About a pint low. Or a puke tank which we are required to run anyway.

Whats the total qts you put in using a deep pan

Depends on the size of the converter.

That seems like alot
Usually 8 quarts.

Posted By: DavidDean

Re: 727 losing fluid from rear vent - 02/20/14 01:55 AM

When I changed my 904 to a rear vent I installed a sintered brass vent. It always seemed to push fluid out with that vent. I changed to a free flowing vent and it really helped but would still push some fluid out. I finally installed a puke tank and no more leaks.

Posted By: Dartlover67

Re: 727 losing fluid from rear vent - 02/20/14 02:36 AM

Puke Tank 4 yrs ago and have not had a problem since.

Posted By: CRIKEY

Re: 727 losing fluid from rear vent - 02/20/14 03:16 AM

Stick a catch can on it to confirm 100% its coming from the vent.

Posted By: 540dust

Re: 727 losing fluid from rear vent - 02/20/14 04:36 AM

Typically the really deep pan trannys are the ones that do this, you should make sure its not over-filled and remove some fluid if necessary, that can help. If that doesn't do it a catch can is pretty much your only choice. I started drilling the bleed hole in the high drum piston instead of the drum so the fluid doesn't flood the stock vent(blows it rearward instead of forward at the stock vent), then I can just use the stock vent, and do not convert to rear vent, this solves the issue. Otherwise, run a puke tank.

Posted By: J_BODY

Re: 727 losing fluid from rear vent - 02/20/14 03:38 PM

Thanks for the tips guys.... might have to go with the "Band-Aid" puke tank deal. We've had three transmissions with the rear vent and this is the first we've dealt with this. All have deep pans, all ran to where there is just fluid at the end of the dipstick. It's just strange that it suddenly popped up. My dad ran the car for a couple years and as I stated, I'm sure as much fluid that was coming out it would have been an issue with him. Other than the obvious lower hp engine installed, I ditched the heavy hydraulic line that was being used for cooler lines, and I changed to a resivoir style trans cooler....which now has me thinking. Maybe on launch having all that fluid at the front of the car is causing this. I Might try rigging some ends and maybe using the old cooler that he had mounted to the radiator.

Posted By: Leigh

Re: 727 losing fluid from rear vent - 02/21/14 08:53 AM

I run mine to the oem 1 pint low mark. I can see your point, that what used to work, now doesn't. I've followed these types of threads for years, and nothing cause related has surfaced. As you know, that area of the trans is totally open, and away from the pressurized oil. At least it is, if the gov support is plugged (yours is), and the sealing rings are on the right land (again yours is). Good luck.