SINY993er

Hello All - Looking for some advice on gear replacement. 3rd Gear started making some terrible noise at my last event. After bringing it to my shop, they told me I need to replace 3rd gear.

Since they need to open the gear box, they suggested upgrading the synchros, forks and, obviously, putting in a shorter gearing.

The short gearing sounds great, but the cost seems to be in the $10K range, which is way out of my budget.

Here are my questions:

1. Is the synchro and fork upgrade really necessary?
2. Any idea what a rough estimate of just replace 3rd gear and wear/tear items?
3. Any other advice?

Thanks

jscott82

For a track car?

The forks are definitely a weak spot, I have one on my desk that the PO cracked... They are brittle cast pieces.. I upgraded 1-2 and 3-4 with billet, as those are the only ones I use on track.

Syncros, I think everyone with a track car "upgrades" to steel... I did, just because thats what all the cool kids were doing... Not sure if there was real value or not...

The guys at guard definitely know their stuff.. If there is anyway to send the box to them or at least have your mechanic consult with them... For a track car there are some other longevity goodies that PMNA called out that could use some attention.

Might as well update the diff while you are in there...

I think the bill was close to 7k when I did mine... That was just updates, did not replace gears.

Sword_of_the_Spirit

Upgrade to a RS/cup gears. The expense is definitely front loaded, but you can get some money back with spare gears near term. Seeing that this is a track vehicle with known Rennlist history, the expense on the box should nearly I've seen around 75% premium which equates to 6-9k) come back on a vehicle sale.

A revised box is highly desired and will command a higher vehicle value as opposed to another. This isn't a small upgrade and is considered better than throwing money into the engine..... I'm sure you know that.

os993

What is your budget? I would highly recommend this build, if there is anyway you can swing it. I did it. 2nd thru 6th. Steel synchros, guard gears, new fork. Worth every penny. I did it almost 13yrs ago. Also threw an RS LWF and clutch. You know, while being in there, hehehe..... Total cost back then was around $10k, if memory serves me right.

Martin S.

I did what os993 did. The biggest payoff, that proverbial 2nd to 3rd lag is gone...and I for one, don't miss it a bit. I have never read on Rennlist or elsewhere, stating that re-gearing the 993 was not worth every cent. And don't worry that short gears will decrease the value of the car.....all it will take is one demo ride for the prospective buyer to realize the exquisite nature of this mod....the down side, you won't be going 175 mph anymore, typically 150ish is tops, waaaaaa waaaaaa If the prospective buyer is not willing to pay a premium for this upgrade, find another prospective buyer.

The "while you are in there WYAIT" rationalization is hard to defend against. Keeping in mind, you'll pay $600 + for a new stock 3rd gear, $50 for the new synchro + the cost to R&R the tranny. The mechanic will probably find some other worn parts, bearings?, possibly other gears as well. So at a minimum you are probably looking at close to $2,000, and you will no more peace of than you had prior to the 3rd gear failure. Maybe those other worn gears are 50% worn, do you replace them now, or on the next R&R? A total rebuild with 3rd through 6th gears is from $8,000 to $10,000, 4X to 5X more money for a 100% overall improvement

I didn't want to take any chances on such a scenario evolving, so just like os993, I replaced 3rd through 6th with custom gears sets, installed 1-2, 3-4 forged shifting forks and steel synchros across the board. Another WYAIT mod, I had done, had several holes drilled for a potential transmission cooler, should I want to do this in the future, and tapped a hole to install my AiM transmission oil heat sensor.

Prior to the rebuild, I concluded that didn't want to spend the $2,000 + extra for a new mainsheet (Assuming I could find it) which would give me short 1st and 2nd gear. I didn't have a problem with stock 1st and 2nd gears.

I had the work done by Lance Aspesi at his one man shop in Van Nuys, CA, about 2 years ago. 100% satisfaction. Would I do the same work again? Damn straight I would. Hopefully there is a Rennlister with short gear in your area...with a brief demo ride, you'll be convinced of the value of this modification, short gears.

Jlaa

I followed both Martin S and os993. Click on the link in my signature for the details - in essence i replaced gears 1-5 with gears from Matt Monson - Guard Transmission - including a new mainshaft to get first to 3.500 ... And used a 6th gear from Porsche MS... Quiet cruising gear. Steel syncros, etc. Bill Rader in Las Vegas did the gearbox work. I used a new stock dual mass flywheel to maximize civility. The gear stack I chose, including 2nd gear, is pretty short and the results are fantastic. Most of my fun driving is low(er) speed technical work with 90pc of the driving in gears 1-3.

Bill Verburg

For track use upgrade everything and add a cooler and Guard LSD if you can swing it, but at least do the internals
the forks are wimpy cast pieces
the bearings have plastic shells that melt and fail
the syncros are brass, you want steel
the motorsports dog teeth have a steeper angle that makes track shifting much more quick and secure

You can't change just one ratio w/o affecting it's neighboring gears

The right and expensive way to do it replaces the main shaft to get a taller 1st, from there you can build a custom gear stack that suits the torque curve of the engine better.

SINY993er

Very helpful...going to review these options with the shop today.

Appreciate the advice/info.

earossi

Or, you can do what I did 2 years ago and put out a WTB ad for a MotorSports gearbox that has all the upgrades Bill referenced. I ended up changing its sixth gear for cruising. The seller refreshed the box and documented his work. I got the tranny for about $9k and then sold my /20 for $2.5k for a net investment of $6.5k. The absolute best money I've ever spent on my car.

Mark in Baltimore

Anthony,

Sorry to hear about the box. Don't forget that you already have a Guards LSD in the transmission. If third gear got lunched and you're on a budget, I would just replace that one and be done with it. With forks 1 through 4 having been upgraded to steel or forged versions, along with 3rd and 4th gear steel syncros, selector shaft and 3rd and 4th shift sleeves, your gearbox has a lot of good upgrades designed for track use.

SINY993er

Hey Mark - thanks for the advice yesterday and on the board.

After some thought, I'm most likely going to refresh the box and go with a shorter gear set. While expensive, I'll feel better knowing everything is "new" and updated. I would hate to just replace 3rd and then have another gear go and have to spend the money all over again.

Plus the car will feel a bit quicker...will keep you posted.

BTW - I love the car!

Mark in Baltimore

Nice. Just be sure whoever you let drive the car understands "mechanical kindness". The car was near-bulletproof for me.

Glad you still love it!

jscott82

Not sure what your long term plans are...

One thing hing to keep in mind... you will never be able to race the car if you change ratios...

My thoughts... There are hotrods and there are race cars...

OverBoosted28

I hate threads like this. They cause anxiety, over things "I need", which I can't afford, and assume that I will be "forced" to submit to at some point.

race911

I certainly have. But maybe the determining factor is the amount paid for said ratio change. In my case, it was zero. Car would have been priced the same with a stock box. (Oddly, a stock box was thrown in as part of the spares package.)

But back to the ratios. As I've said many times, out here what works for Thunderhill and Sears is a 2 sec/lap penalty at Laguna. If only you could change the ratios out like in a Hewland.

Sure you can. You just may be thrown in a class with some factory race cars/exotic home builds. And no matter your inner Hamilton, Vettel, etc., welcome to starting the race by hearing engines go on throttle, rather than seeing the green flag.