Is this a matching gear set?

[mikedsilva]

I'm looking at a replacement set for 2nd gear for my 915.

Trying to ascertain if this is indeed a matching gearset. Both gears appear to have the same manufacturer stamp "73 H X *" but only 1 has the handscribed number "9972".

The smaller gear does not have this number scribed on that I can see.
I'm inexperienced with trannies so any advice is appreciated.

[jpnovak]

9 73 should be year of manufacture. HX should be the gear ratio. The acid etched numbers are the individual S/N. They usually match the hand etched.

[mikedsilva]

Originally Posted by jpnovak

9 73 should be year of manufacture. HX should be the gear ratio. The acid etched numbers are the individual S/N. They usually match the hand etched.

Yes, so without the hand etched numbers on the smaller gear, there is no way to tell if they are indeed matching?

[Matt Monson]

That fixed gear looks kind of hammered. I would keep shopping. 1973 is the first year of a 14 year manufacturing run. I’d be looking for a gear made in the 80s.

And no, we can’t tell if they are matched but most likely they are.

[mikedsilva]

Originally Posted by Matt Monson

That fixed gear looks kind of hammered. I would keep shopping. 1973 is the first year of a 14 year manufacturing run. I’d be looking for a gear made in the 80s.

And no, we can’t tell if they are matched but most likely they are.

thanks Matt.

[Mahler9th]

It is a matching gear set.

It sounds like you have had some problems-- I think you should consider buying new gears. I can recommend the Guard Transmission gears. I have been using them for nearly 20 years.

[KTL]

HX is a very common 2nd gear ratio used in nearly all the 915 5-speed transmissions. You shouldn't have a hard time finding a decent used pair if that's the route you'd like to go.

I got a very nice HX from Mike Bruns. He may still have a few pairs on hand and i'm sure they're in good shape.

915 Gears

[kevingross]

Originally Posted by Matt Monson

That fixed gear looks kind of hammered. I would keep shopping. 1973 is the first year of a 14 year manufacturing run. I’d be looking for a gear made in the 80s.

Gonna agree with Matt here. The chips at the end of the teeth in the first photo are certainly not a good sign. Little hard to be sure from the photo, but the tooth surface condition in the third photo (same part) looks dodgy -- could be the photo tho.

[Mahler9th]

As KTL has indicated, there are likely plenty of used HX gear sets around. If that one is not suitable for your application I am happy to suggest several resources that may have a better set.

For example, Partsheaven here in Norcal might have an Hx set or perhaps a few-- I hear they are liquidating everything. Good friends about 20 minutes from where I live.

Be ware that likely many dismantlers like them have not been able to buy as many 911 cars as a decade or so ago... so you may have to call around.

As we discussed via e-mail, I doubt your 915 situation is a worn out 2nd gear, but I am no expert. Perhaps folks here can recommend someone near your location that can help you get your issues sorted quickly.

Again, there is NO question that is a set-- I am pretty sure I got it used from WEVO-- they sold it to me as kind of a favor years ago. Whether it is better or worse than what you already have is hard (perhaps impossible) to assess by e-mail.

[stownsen914]

Sometimes the etching can be hard to see, especially on an old gearset that’s been around the block a few times. I had to use good light and a magnifying g glass to make out the etched numbers on a 901 gearset once. Maybe a moot point in this case