maspirito

I have recently destroyed Third gear in an LS 3 conversion 944. I was told that there are some aftermarket gears that are more robust. Does anybody have a contact or the name of the company that produces these? Thanks for the help

harveyf

A few years ago I came across a company in Austrailia that advertised stronger gears. Their prices were pretty steep.

You might consider getting a set of stock gears "treated". The form factor of the gears is going to be hard to improve (thickness, tooth shape, etc) but there are standard processes such a heat treating and nitriding that can be applied to metals to add strength.

You might want to post over on the turbo forum. That seems to be where the drag racers hang out.

Not trying to be snide but you might want to evaluate your usage of the car. If you're doing lots of smokey burnouts from a standing start, dropping the clutch from high rpms, that is not what Porsche designed that transaxle for.

maspirito

Yeah I think there are providers of heavier duty gears someplace. Just need to find out where they are. The car is used as a track car the incident happened on a down shift into turn turn 10A at Road Atlanta. The 525 hp and the 330 tires on the back put a little bit of stress on the transmission.

Jay Wellwood

"The 525 hp and the 330 tires on the back put a little bit of stress on the transmission."

Not to menton the roughly 2700#'s being forced into the equation with the gription of those massive meats.

Dayum...

GPA951s

Contact Dimi at Flyinghorsemotorsports.com He is excellent with these trannies... On a different note, you are asking a transmission to hold together almost 3X the power it was designed for... If its a N/A Trans.. Just go out and spend 300 bucks and buy one.. Then buy another one as a spare, They are so simple to swap out, even at the track not a big deal. With that rubber and power all it will take is one missed heel/toe downshift and bang... I was at a track event when a guy went into 1st instead of upshifting to third... Exploded the case halves...and oiled down the front straight.. and he had big tires on... It amazes me how robust these trannies are considering they are 30 years old and what they were initially designed to do...
- What you really need with that kind of power is an Allison 1000

harveyf

I sent a N/A transaxle to Kevin Gross for rebuild last year. He can fill you in on the details but there were several bearings in the transmission that were "wallowing out" their mounting holes in the case. In general, as wear occurs, the gears may still maintain a mesh but the contact becomes suboptimal. You can imagine if the mating gears are allowed to come apart slightly, the load transfer goes more towards the tips of the gear teeth, increasing the moment arm while reducing the contact area. Not a good thing.

As I'm sure you know, lot's of guys are running 944's with LS engines. Hal Bayless comes to mind. He has a very nice LS 944 and has run thousands of laps at RA. I don't know, maybe some are putting in trannies from a 951 into their car. But I would recommend a first class rebuild if you are going to continue at LS power levels.

maspirito

I have 2 951 transmissions.

KevinGross

For the 944 S/S2/Turbo, your only option for different gears are parts made by Albins in Australia, distributed by Retro Sport in the US. They offer different gear ratios. However, as far as I am aware they are not (claimed to be) any stronger than the factory gearsets. May be worth checking whether Albins makes any statements otherwise; I just don't know. I have installed a few of these for customers, quality is good, not inexpensive.

Your best options for helping longevity of your stock 944 transmission would be:

• Make sure it is set up correctly: pinion depth, bearing preload, etc. Get it built by someone who has all the factory tools and uses them to do the job thoroughly and correctly.
• Do the maintenance, to include fluid changes and, as needed, service to the internals.
• Shift properly. Learn to heel-toe if that's not something you're already good at. Under no circumstances dump the clutch to do a first-gear traffic light or NASA start burn out.

If you have an eight-valve, normally aspirated transmission, during service have its pinion gear checked for micro cracks, for example using a dye penetrant test. Even better, there is an improved ring-and-pinion for this transmission available: worthwhile upgrade. The set has the same ratio as the original, so it's legal for PCA Club Racing etc. And the pinion is stronger, it is the same pinion gear as was machined for the 944S transmission. Requires swapping the diff carrier, but it's an inexpensive part at present.

I don't believe the 968 transmission is significantly / any stronger than the 944 Turbo. It is popular to say that it is, but I have seen nothing to validate that claim. Parts for it are generally available, but more expensive than the 944-series boxes.

Good luck!

maspirito

Thank you that was the answer I was looking for.
Very informative