PPG straight cut dog gearset
 

Currently having gearbox rebuilt with new PPG dog gearset. The gearbox rebuilder who has over 30 years experience rebuilding gearboxes for rally cars has raised a concern with 4th gear.

While overall he thought that the quality was top notch, he was not impressed with the way the dog ring was welded onto 4th gear and stated that it would most likely break very easily. He has seen better designs and he considered my previous PAR set 4th gear to be better. Although overall he stated that the PPG was better than the PAR, which in my experience with PAR would not be difficult.

Has anyone heard/had PPG 4th gear fail or is he needlessly worried. or any failure with PPG gearset.

It's not 4rth gear that the dog ring is welded onto the Gear, it's the 3rd gear on the 1st motion shaft, and yes I have one sitting in my garage with crack radiating out on every dog originating at the end of each of the welds. It was found before it let go, but wasn't far away from doing so.


---john---

It looks like my Greek is not so good after all and I got lost in translation, but it seems the guy knows what he is talking about.

John

How long did it last?

Any comments on this from PPG?

How much hp/torque are you running?

How much to replace?

I am a bit disappointed that this could happen, as I thought that by now these type of issues would have been sorted. After all PAR in conjunction with Rigoli started designing a dog gearset in 1998 and released in 2001. Plenty of time for all manufacturers to have realised weaknesses in the gearbox and their design. I seem to recall that my PAR box was not welded on. The problem with that gearbox was it alowed you too select two gears at same time with interesting results. Would have thought that design/strength would have moved on a bit.

I chased up PPG and Tony Rigoli for an answer to this and have some good news.

PPG reply:

The question you ask is a common one. The engineer telling you that our 3rd gear dog that is welded on will break is not correct. Initially, some early style 3rd gears had a ‘cracking’ issue. This was addressed and the necessary manufacturing design changes were implemented, and as such there has been no failures since with the ‘welded’ dog ring failing.



Our PPG gearsets are far superior to the competition products, and yes if this part happens to ‘crack’ as you say, we will cover that part under warranty.


TRP reply

To be truthful we haven’t had any break on the weld, it is a special weld for that purpose. The main problem with his early sets was that 1st gear would weld itself on the shaft (due to poor lubrication), this would usually happen when your in 3rd or 4th so either one of the gears would break.


We will have to wait and see, but if TRP have not had any fail I am happy.

Paul