Hi guys I’m doing a vent relocation on my 727, blocking the vent in the top of the pump housing and installing a vent in the rear of the trans, I’ve seen them installed in the rear of the trans housing just ahead of the extension housing flange and ive seen them in the front of the extension housing just behind where it bolts to the trans housing, anyone have any fores and against for either location???, suggestions?

Ours is in the top of the tail shaft housing just behind where it bolts to the case. Had to hook it to a catch can because it will push out a little fluid during a run. At least it did on ours.

https://www.forbbodiesonly.com/moparforum/threads/727-torqueflite-rear-vent-install-question.146442/

nice lil discussion with pictures and everything...

I use the same "quick connect" discussed in this thread.

The trans in my old Mirada was the plastic push in vent and never leaked a drop. My current trans will push fluid out during a pass, thus the catch can was installed. I've also noted the current vent is not in the same location as what the Mirada had. Believe it was the same as the picture noted in the link.

Put it where the picture shows. If you put it in the tail housing the park gear will fill it with fluid.
Doug

Back of the case so that it is open to the cavity under the rear support. I like it at 11 o'clock above the bolt hole on top left as long as there is not a clearance issue. Just below the bolt hole would be my second choice.

My governor has been removed so I put mine at about 1 o'clock on the tail shaft housing, over where the governor would be. I also fashioned a small internal cover out thin aluminum sheet. It hasn't been ran yet so I don't yet know if it's going to puke or not.

Thanks guys, great info,

When I built my 904 John Cope told me not to add a rear vent. It was also mentioned in the link Cope no longer vents at the rear.

When I added my trans brake I was told if I drilled the piston (I did) instead of the drum I wouldn't need to relocate the vent. Guess what? It blew fluid out the factory vent so the transmission had to come back out and partially apart to move it.

Done many, never had one leak where I put them.

That is what Joe at tranz act told me to not to move it to the back

Ok so I’m not running a transbrake, so what’s with all the main builders now not moving the vent?????
I kinda liked the idea of moving it and running to a catch can primarily to ensure any leaks were not converter or pump related etc???

No brake: Relocated vent isn't necessary. Brake with drilled front clutch retainer or piston, relocate to the case as shown.

I assumed a brake was being used.

Ok so without a brake it’ll categorically never push oil from the factory breather location??
If there is at all any chance, I’d rather put a rear mount breather on the trans primarily to eliminate false reads of front seal leaks etc, is there any negatives at all in relocating the vent???

Normally the stock vents don't leak, but I never say never. I've never had one leak at the rear and I've taken brakes out and put regular manual units in without plugging it. I wouldn't put a vent in the rear with a governor still in it. BUT If the guys who do it all day, everyday say not to move it, they have a reason and I'm not going to argue with them.

My advice is to be cautious of drilling the case close to the sealing surface. Then be even more careful tightening the tapered pipe fitting with the hole so close to the case edge/ sealing surface.

Thanks guys, there won’t be a governor fitted at it’s a manual pattern VB, I’ll give it some serious concise ration, I’d kinda rather not install it but if there was a very valid reason no matter how trivial I willl

what seems to be the reasoning for not putting the vent in the rear of the case?, for years it was the accepted practice to do just that and now it's appears to be taboo, I have always put the vent in the rear of the case and plugged the front one.

But you did that with a brake, I never put it
the rear if NOT using a brake

I thought they ment in any combination, maybe I mis undestood.

I don't know why it went out of fashion. They're saying Cope and Tranzact don't want it done. I don't know the reason. All I know is I've done it for years on units with a brake from Griner and Protrans with no issues. Perhaps they stopped with putting the small hole in the high drum which I understand is the main reason for moving it. I'd like to hear from one of them for a clarification.

I know in the (Carl Monrow) 727 book it says to
move it and I did

My last trans was built by A&A. It was the only trans I had with the vent moved to the rear, and the only trans I had that leaked from a vent. I ended up running a nylon tube up to the dipstick to prevent the leak from oiling down the car on a heavy pass. Hardened shafts-so no governor. Just didn't work for my combo. The tube solved the problem so I guess it turned out fine in the end.
I could see how a drilled drum would cause an issue with the pump located vent. Maybe they vent the drum differently now so relocation isn't needed?

I am not running a brake. When I posted my original response a brake was not mentioned by OP.

I've had mine apart 2 times for inspection in the last 3 years. Now has 350 passes in a 9.0 car without a brake. Vent is in the back. It is in the suggested location. Tube to a catch can at the rear bumper. Catch can has never leaked or been emptied. Both times the inside of the bell housing has been completely dry. It hasn't had the pump seal replaced since originally built.
Doug

pipe threads will wedge the surrounding material with the fitting, and there is a recommended wall thickness surrounding the fitting for different materials, but i don't know where my chart for that is. if you have one side of the surrounding material much closer to the edge of the hole [think of a very offset hole], the wedge effect will concentrate on the "thin" side more than the "thick" side, promoting a crack to form. also, most seem to have a tendency to crank on pipe threads so they don't leak.

The vent doesn't have to be threaded, I have one that I think came with my brake that is push in.

I don't drill and tap. If I did, I would use 1/16NPT. I use these.

I run one of Cope's transbrake valve bodys and don't honestly remember John telling me to NOT put the vent in the rear, when I put the new billet steel high gear drum in I drilled the piston which pushes the fluid toward the rear,, with that said I have not had a issue from the rear vent.

You can also use other materials to ensure that the alloy material is essential in this case. I once put a panel for myself and made a mistake with the materials. So it did not last a year, as it broke and began to rattle. So now I constantly look at what is where. To then know what is better to take products for yourself and your loved ones. Recently, there was a question about the air conditioner and its choice of truth. Who not to ask everyone complains about something? I even started to think about not taking it at all.