Toyota 5-speed bell housing drain hole

[Lin]

I apologize but I have tried to search for this with no luck. I think, not too long ago, someone posted about drilling a hole in the bottom of the Smitty bell housing similar to what was done on our original gearboxes to allow oil to drain. I am looking for some information on the best place to drill that hole. Perhaps I have the wrong Forum/email list, not sure. Can anyone here help me with what I am looking for?
Thanks,
Lin

 

[steveg]

Lin,
I actually drilled an approximately 1/8" hole at bottom center in the flange of the bell housing, right against the rear engine plate.

I wasn't too concerned about the Toyota trans leaking but wanted to know if my engine rear seal installation was leaking.

 

[roscoe]

I just receieved a 5 speed kit. I would imagine that with no gasket between the bell housing and the mount plate, that you will know if either your rear crank seal or trans. input seal are leaking without a hole . A hole in the low spot can't hurt and you might see any leaks sooner than you would without a hole. I suspect the original bell housing had a hole because they knew it would leak and might leak fast enough to fill up the housing so as to hit the lip of the flywheel, clutch housing and disk. ZZZZZZZZ, slip, slip :fat:

 

[red57]

I don't remember why but for some reason I didn't want to drill a hole when I installed mine 20 years ago. I filed a couple of 1/2 circle grooves with a rat tail file in the bottom of the flange/engine plate joint. I too, wanted to know if the rear engine seal was doing it's job.

Dave

 

[Lin]

Thanks guys! Dave, since you obviously have your gearbox out of the car, if convenient, could you measure the thickness of the bellhousing flange where you have your filed holes? If I drill a hole (the gearbox is in the car) I would like to know in advance how far I need to go.
Thank you!!!
Lin

 

[red57]

Lin,
The flange on mine is just over 1/2" thick (.510) front to rear and vertically (between the two grooves I filed) it's 1.210".

BTW, in my picture you can see a horizontal line running part way across the flange about half way up - that marks the edge of my OEM steel rear engine plate (bellhousing flange hangs quite a bit below the engine plate) and it measures about .630 from that line to the top of my drain grooves

I don't know how consistent these are but I bought kit from Smitty in about 1996-7 and I don't know if any refinements/revisions have happened since then.

Need more, let me know.

Dave

 

[Lin]

Thank you, Dave.
I guess I will drill a 1/8” hole about a 1/4” in from the edge of the flange and will expect to go about 1 1/4” deep. Do you think it best to go through the flange as Steve did as opposed to moving rearward a bit? Where is the low point where oil would settle?
Lin

 

[steveg]

Thank you, Dave.
I guess I will drill a 1/8” hole about a 1/4” in from the edge of the flange and will expect to go about 1 1/4” deep. Do you think it best to go through the flange as Steve did as opposed to moving rearward a bit? Where is the low point where oil would settle?
Lin

Lin,
I just placed the drill against the steel engine plate and drilled up through the edge of the aluminum flange. The resulting hole will look like Dave's grooves. On second thought, it's probably 3/16".

 

[HealeyRick]

Lin,

Make sure you put a cotter pin in that hole to keep it original looking.

 

[steveg]

Lin,

Make sure you put a cotter pin in that hole to keep it original looking.

Since it's a Toyota trans, that would have to be a metric cotter pin.

 

[red57]

Lin, The low point is at the flange to engine plate joint (see pic) - it's minor but there is a definite downward slope towards the front in the bottom of the bellhousing. I think that's why I went for the grooves originally (although it's been over 20 years and my memory isn't what is once was ). I think I would do just what Steve did and then you would be assured of hitting the low point - in fact it would have been a lot easier than filing grooves .

Dave

 

[Lin]

Thanks to you both! Got it.
Lin

 

[Lin]

Just to close the loop, I did drill the 3/16” hole. At first I was concerned because when I “broke through” the oil started dripping but after a couple of minutes nothing was coming out. What came out had accumulated for the last ten years, albeit light use. So, I figure nothing unusual here. I have a drip pan installed so I will be able to monitor oil seepage. Thanks.

 

[dougie]

Nice Epoxy Flaked floor Lin, I expected nothing less. :friendly_wink:

 

[Lin]

But, of course!
:smile-new:,
Lin