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914World.com _ 914World Garage _ Time for transmission assembly...

Posted by: bondo May 14 2005, 09:27 PM

Remember a looong time ago I put together a classic thread about where all the bits go in a 901? Well I'm finally getting around to putting together my "one trans made of many", with an H gear for 5th.

Does anyone know any tricks regarding how to make a 901 stand up to a V8? I've heard that upping the differential bearing preload helps, but I don't know how to do that or by how much. Also, if anyone near me has a dog teeth removal tool, I'd love to borrow it

Posted by: ClayPerrine May 15 2005, 07:34 AM

Use an billet intermediate plate.

Lock out first gear.

If you want to get really radical, put a gear oil pump and cooler on the trans, and put a sprayer pointed at the input shaft bearing in the intermediate plate.

Run swepco.

Posted by: Red-Beard May 15 2005, 08:01 AM

This is one time I agree that Swepco is worth the investment.

Posted by: bondo May 15 2005, 10:28 AM

First gear is getting left out, and locked out. (I already sold all my good 1st gear sliders and dog teeth )

I'm tempted to do the sprayer/cooler thing. How hot do these get? does it REALLY help?

I can't afford the billet goodies, but I may make a steel reinforcement plate to bolt on top of the side cover to reinforce it. I searched the archives and found my answer about preload. Looks like I need to up it to .008 - .010.

Swepco 201 or 212? (Renegade reccomends 212, I have no idea why)

Posted by: ClayPerrine May 15 2005, 11:13 AM

QUOTE (bondo @ May 15 2005, 10:28 AM)

I'm tempted to do the sprayer/cooler thing. How hot do these get? does it REALLY help?

The cooler will help, but one of the big problems with the 901 gearbox is that the input shaft bearings sit above the oil level, and only get splash oiled. So adding a sprayer will increase the life of the bearing and lower the heat that is transmitted to the intermediate plate.

Posted by: Mr.C May 15 2005, 11:22 AM

Make sure to take plenty of pictures cause I'm following this one.

Posted by: bondo May 15 2005, 01:32 PM

Well here's the idea I've been kicking around:

If the ring gear will spew fluid though the vent if the vent is not rotated the right way... I should be able to use the ring gear as a pump if I design it right. I could make a pickup tube that lives very close to the ring gear (at the bottom, at a tangent, under the fluid) that will take fluid that is thrown off the ring gear and plumb it up to the input shaft. If I don't worry about cooling I could make it fit entirely inside the transmission. (no added opportunities for leaks) If I plumb it outside the trans and add a little cooler, chances are the pumping effect wouldn't be enough, but who knows.

Posted by: bondo May 15 2005, 01:37 PM

Also, what's too hot? I could put a sensor in the fluid and monitor temps.. the if it gets too hot, (whatever too hot is) I can add a cooler and pump at a later date.

Posted by: ClayPerrine May 15 2005, 06:51 PM

QUOTE (bondo @ May 15 2005, 01:32 PM)
Well here's the idea I've been kicking around:

If the ring gear will spew fluid though the vent if the vent is not rotated the right way... I should be able to use the ring gear as a pump if I design it right. I could make a pickup tube that lives very close to the ring gear (at the bottom, at a tangent, under the fluid) that will take fluid that is thrown off the ring gear and plumb it up to the input shaft. If I don't worry about cooling I could make it fit entirely inside the transmission. (no added opportunities for leaks) If I plumb it outside the trans and add a little cooler, chances are the pumping effect wouldn't be enough, but who knows.

There is a boss on the opposite side of transmission case where the vent would go if the transmission was in a 911. That is directly over the ring gear. If you put the transmission from a 911 in a 914 by flipping the differental, and you don't change the vent location, all your gear oil will be pumped from the motor very quickly.

On that subject, you could drill and tap that boss, then install an AN fitting. Plumb that to an oil cooler, and feed the return in above the input shaft bearing. It would then lube the input shaft bearing with cool gear oil everytime the car was moving, and it would add very few new, and no new moving, parts.

Posted by: jr91472 May 15 2005, 07:21 PM

QUOTE (ClayPerrine @ May 15 2005, 09:13 AM)
[/QUOTE]
The cooler will help, but one of the big problems with the 901 gearbox is that the input shaft bearings sit above the oil level, and only get splash oiled. So adding a sprayer will increase the life of the bearing and lower the heat that is transmitted to the intermediate plate.

So what happens if you over fill the tranny? I mean, if while the trans is out of the car, turn it on it side thus increasing the amount of oil you can put into the tranny before it starts running out the fill hole.

would it be possible to increase the level up to the point where it would reach the top bearings?

just wondering......

Posted by: ClayPerrine May 15 2005, 07:23 PM

Never tried it. I figure it would pump the fluid out of the trans through the vent and make a real mess.