Pinion Failure-Why?, Gears in disarray Options

[groot]

It certainly could be my fault. I didn't check/set/change the pinion depth when I re-assembled this gearbox 2 seasons ago.

At Mid-Ohio this weekend I couldn't catch 5th... which led to pitiful laptimes.... in the first session. So, I adjusted the linkage thinking that the fork just wasn't pushing the engagement ring far enough.... next session, same thing. I didn't take the start and watched from a corner station.

So, after that I checked the shift linkage, no major issues. I pulled the shift rod holder to look at the shift forks, again no major problems. So, I decided to pull the gearstack and that's when I noticed the pinion pictured here..... still not sure what the problem was with 5th, but it is probably worn synchros.

I rebuilt this gearbox before the start of last season and only refreshed it with parts I had....flipped synchros, better dog teeth, a few gear changes and no bearing changes. I'm only running 150 ponies through this box.

It looks like the pinion isn't meeting the ring at the right angle, but I'm just guessing. Does anybody have input????

.............sorry for the crappy pics, my camera wouldn't focus on the part I wanted ot show.

[Brad Roberts]

It wouldnt go into 5th because a piece of the pinion gear was blocking it!!

Welcome my friend to the most common failure in 914 tranny's that we see racing them (IMG:style_emoticons/default/beerchug.gif)

No joke. This is something we see regularly against the race engines. 1-2 a year that is.

You had a bad R+P to start with. I doubt seriously it had anything to do with your pinion depth. Several years back I had multiple conversations with Roger Sheridan about how difficult it was to find good 901/914 R+P's here in CA. He blew up his 901/914 box with the exact same results you have shown us here. He went to the 915 for the very next season and hasnt looked back.

What I would do: collect 3-4 R+P sets and have them X-rayed and cryo'd before having a known good tranny place set the pinion depth for you (I'd send it to WEVO personally) send it with just the input shaft/pinion shaft/diff in place. You can do this by only assembling the spacers/gears on the two shafts into the intermediate plate. He has to be able to torque down the two large nuts.


Bottom line: make it VERY easy for the shaft/shims to be removed from the tranny intermediate plate so they dont have to fumble with all the other crap associated with setting the depth.


B