Well, we did. Knocked the edges off the 2nd gear dogs, wouldn't go into or stay in gear.

Anyone who has needed to buy replacement parts for the PPG box knows how crazy expensive it is. Well, we decided to see if we could repair the damage.

So, we had a custom cutter made to clean up the damaged face. It has the correct angle backcut and radius on both the lower and upper corners. All dogs now mate with the dog-ring perfectly again! It looks like we could even possibly repair the dogs once more if it was needed. We are pretty happy with the result.

Before (Damaged):


After (Repaired):




Just figured you guys would appreciate this. If anyone needs this repair made, we can perform this for you for a very reasonable amount vs. the cost of a whole new gear and shipping from Australia. We all know how expensive this sport is, and every little bit helps!

 

Only thing that worries me is the amount of material left and if each individual dog has the same amount of material removed so it will mate with the slider correctly and evenly....

I would look into your shift mechanism and or your electronics if your using a shift cut.

 

I think you will have a problem with this as you have now gone through the case hardening so the dog faces will wear out even quicker than before.

 

i agree but i guess we'll see

 

I've seen this problem frequently (Quite sad). Also seen it repaired by building up material via TIG and then reshaping it in a mill like you seem to have done. But in all truth they realy take a beating.

I fear also that the weld wont hold up but it would be crazy not to try.

 

Liberty takes a beating as well.

 

Wear happens from missed shifts, with any trans, even a $20k+ Xtrac. It sucks, but when the dogs crash at high speed, it happens. They can only take so much abuse. When a shift is not missed, this will not happen.

 

Right. We all know why the damage happened - that is not the point of this thread, and has nothing to with the quality of the PPG gearset. Obviously power was applied before it was fully in gear.

This wasn't done by hand if that's what you are thinking. It was all measured via a CMM and cut by high end CNC machines at a local aerospace/defense company.

All dogs mate perfectly with each lug on the slider, all angles match the original part, and there is plenty of material left.


The material is thru-hardened, I'm not worried about the hardness. The surface finish is not the same as before, true. And the damage was due to driver error.

This is just an easy, cost effective way to be able to reuse a damaged gear. Nothing more, nothing less. And it was done correctly, not in someones shop with a dremel.

 

The material is thru-hardened, I'm not worried about the hardness. The surface finish is not the same as before, true. And the damage was due to driver error.

Below is a quote from PPG's website stating that the gears are 'case hardened' and not through hardened as is the case with most automotive gears.

The last phase of the gear set production is heat treatment (case hardening). This is not a new approach to strengthening metal componentry and most clientele of the automotive industry would be familiar with the process of parts being dipped into a heat treating salt bath containing various elements but most importantly carbon.

The “Controlled Atmosphere” heat treatment process Pfitzner Performance Gearbox apply is a more precise and refined method from the original salt bath heat treating. Using a computer controlled atmosphere (furnace) where carbon and other elements are monitored and maintained at optimum levels via highly advanced software and sensors, ensures accurate and efficient heat treating, consistently producing a well hardened and strengthened product for Pfitzner customers.

High temperature levels are produced to attract and infuse carbon onto the surface of the product, penetrating to calculated design depths to harden it. “Rockwell” tests (an international standard of hardness testing) are performed at regular intervals with sacrificial components as a form of ongoing quality control.

Competitor Heat Treating Process
The basic heat treating technique is at times “hit and miss” given element levels fluctuate and more specifically carbon content is “guestimated” producing inconsistencies with this practice. Salt Bath techniques were developed pre the 1950’s and have not evolved since then.

 

You haven't gone fast enough to break that transmission.
-Sam

 

That has nothing to do with how much use a face plate gets. The owner can tear up their gears like this with a miss shift running 12'sas far as I'm
concerned.

Has anyone else had this kind of wear from their super fast cars? I've had accidental shifts in the pits driving around that have sounded rough but gear changes down the track are always direct... Never excessively rough or loud.

 

I've done it with an xtrac, liberty, and PPG. This won't happen in the pits, this is a full power missed shift, a bad one. This does t happen with a light miss, this was one of those ones where you know it was ugly when you did it. Lol

 

i did it with my liberty when I was trying to set up the g force shifter. pain

 

Hi Danny,

Did it cause similar damage to your Liberty?

 

I had the exact same thing happen to my liberty because the g force shifter does not have enough throw. I have since taken it to the machine shop at work and fixed that though. Plenty of throw now! LOL

 

I can totally see it LOL as soon as ya do it your cussing your butt off LOL......

Good luck guys hope it is a fix if noy a temporary fix.....

 

Interesting info. I'm wondering then, does PPG use mild or med-high carbon steel for the gears? Because you can't case harden med-high carbon steel according to my understanding, only mild steel. I wouldn't think the gears are made of mild steel. Since it looks like you make a gearset, maybe you can shed some light on this?

Either way, nobody's gears will hold up to a mis-shift like that, regardless of material or heat-treat used. We planned on keeping this gear as a backup if we needed it at an event, rather than turning it into an expensive paperweight. I'm sure that it will work just fine, and for 1/4 the cost of a whole new gear to recut it like this and make it usable again, I don't see any drawback to it at all.

 

I have two of those damaged little bastards. I would def try what you did. Can't hurt to try.

 

I would much rather try this until i completely cut the dog off then buy a new one... I'm almost positive it will work just like new.. good job..

 

Tony, how does someone miss a shift on an xtrac?

 

Same as with any dogbox, set the ign cut too short and have power come back on before the gear is fully engaged. If you use the clutch it'll pretty much never happen with an Xtrac, but with an ign. cut and strain gage it can.

 

Ok, gotcha

 

Tom @ NRG just did the same thing. I'm curious to see how it holds up compared to the initial state of the gear before use.

 

yeah i saw Tom's on Facebook.. looked pretty good

 

LMAO this is so tru.

everyone is guilty of that.

anyways. OP my hat is off to u for trying to do something instead of giving up & buying new. im shure it will be fine as long as its on point. let us know.