T9 Transmission filler

[Doug Liedblad]

To make it easier to add/remove/ check the transmission oil level.

I got this idea from Blatchat.

The idea is to install a removable plug on the T9 top cover so you can check the oil level, change, or empty it before removing the transmission without the bother of the very limited access side plug.

When first installed I made a dipstick and calibrated by filling to the overflow plug.

I used a short 1/2-20 bolt and nut, with the nut brazed on inside of the cover, an O Ring for a seal. Works fine.

Sean added to this by using an O2 Sensor bung and plug. Better idea as it is a bit larger. You can find the plugs with a crush washer too. These are typically the same thread as a spark plug.

I put mine in the left front corner of the cover, no gears or shift forks nearby.

The cheapest bungs I've found are here:

http://www.urdusa.com/product_info.php?cPath=9_19&products_id=540000098

You can find bungs from many sources but I'd use one with the step and just braze it in. Welding may be OK but it might warp the sheet metal. With the step it cannot fall into the gearcase if the braze fails. Bad noises if this happens so be sure it is secure.

I use a venturi vacuum generator and catch tank (air compressor required) to evacuate the transmission, takes about one minute.

An alternative is this: (shop around for better prices)

http://www.motiveproducts.com/05specials2.html

Doug

[moosetestbestanden]

A couple of questions Doug:

Why braze the bung on the inside? Clearance?

Top cover cannot be tapped?

[moosetestbestanden]

A couple of questions Doug:

Why braze the bung on the inside? Clearance?

Top cannot be tapped?

Edit: sorry for the duplicate posting - my computer shit the bed just as I hit submit the 1st time.

[Doug Liedblad]

Chris

I brazed the nut on the inside as that seemed the way to do it.

No reason not to do it on the outside, at least in my car, as I have plenty of clearance. That's probably a better way with the stepped bung, that way it cannot fall inside if the braze / weld fails - which is pretty unlikly anyhow.

The sheet metal is too thin to tap and hold the plug.

Doug

[Sean]

On Doug's advice, I had this done. Easy for me, because I had the gearbox outside the car when he told me about it. Mine is a stepped O2 bung, TIG welded into the top plate. Photo attached.

edit: "I did this" changed to "I had this done".

[slomove]

Any way to do this with the tranny including top plate installed? I would really hate to yank it out....or to be more precise I am sure not to yank it out just for this purpose.

I was wondering of installing a maybe 1/2" thick square ali or 304SS plate with the big threaded access hole in the middle and 4 small (#10?) bolts to hold it down on the cover plate. Or is the cover plate even too thin for small bolts?

One more question....how to prevent the drilling/tapping swarf from falling inside?

[Doug Liedblad]

Gert

Ya got's ta take it off.

Generally not worth doing until you remove the engine / tranny for some reason.

In Michael Bedards '88 Caterham you could remove it while in the car. I think his engine mounted furhter forward.

I only do this with the top cover off.

Doug

[Sean]

Gert - I removed the top plate from the gearbox, had the hole drilled and the bung TIG welded in place, and then replaced the plate (after laying down some silicone instant gasket stuff to replace the one I shredded when removing the plate). I have yet to fill my gearbox with gear oil, so haven't used it yet. The cover plate is very thin steel.

[slomove]

O.K., I see....well, then maybe next time I screw up something with the engine (maybe I should not say that).

Gert

P.S.: Reminds me I know somebody who put a plug in the bottom of the T9 (right through the center of the annular metal-catch magnet) for easier draining. Not as convenient for filling, though.

[Doug Liedblad]

The drain plug idea is done in the UK by some of the T9 rebuilders. Often mentioned on Blatchat.

The suction method from the top is easier as you don't need to get under the car.

Edited to add the latest convert -moosetestperson's bung.

Courtesy of Chris I have two or three extras for anyone else that is interested.

Doug

[Elv15]

Doug,

I want to make this mod to my gearbox cover - since I have the engine out anyway.... Do you still have a spare bung?

Thanks,

Tom

[Doug Liedblad]

I'll have to look.

You can find them online from several sources. Get the one with step like in the photo and the plug with crush washer.

If you have time send it to me and I'll do it and send it back. If you don't have time for that I may have another option.

[slomove]

I used an oil plug from the auto store with standard thread (maybe 1/2" but forgot) and welded a plain hex nut as bung. If I had to do it again I would probably braze it.