Well I had another Getrag failure. This one was unique from the others. I was rolling along in 2nd gear going ~20 MPH. I rolled into the throttle and the car starting building boost. Near peak torque, 2nd gear just let go. Sounds like is sheared the teeth off of gear. I coasted off Woodward and had a trail of oil following me in. I won't know until I get the trans out and take it apart, but I think this was a gear failure. It will still move in other gears, but you have to put up with rocks in a blender.

Looks like it is time to get the new trans put together (one of the Ebay units with crap gearing). I am going to try to get it together with the gears I want this week.

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62 Buick Special
86 GT, 5-Speed
87 GT, 3.4l DOHC Turbo 415 WHP, 11.9 @ 118
88 Toyota Supra Turbo

Keep us posted. I am especially interested in how the e-bay tranny works out- I assume you are talking about the Quad 4 units a place/guy is selling?

Yes it is the ebay unit. I am going to swap 1st, 2nd and 5th from a Fiero unit.

[This message has been edited by Matt Hawkins (edited 06-23-2008).]

Is this the tranny that you put in before the 07 Power Tour? I am curious if it was rebuilt and if so how long did it last. Many Getrag failures have been traced back to worn diff bearings/weak spider gears, but if this tranny is 1 year post rebuild, then that should not have been the failure mode...

This is the transmission I put in last year. The diff bearing were good and the diff is still intact. I will have to wait and see, but I haven't seen a broken gear before.

quote Originally posted by Matt Hawkins: I will have to wait and see, but I haven't seen a broken gear before.

Probably because no getrag has seen 500hp before!

quote Originally posted by ryan.hess: Probably because no getrag has seen 500hp before!

Well I don't think I have quite that much, but thanks! I have tuned the car a bit since last year. I might be in the 430 WHP range now.

quote Originally posted by Matt Hawkins: Well I don't think I have quite that much, but thanks! I have tuned the car a bit since last year. I might be in the 430 WHP range now.

its fairly sure you are making 500crank hp.

This bearing blew out.

Guarantee you thats what happened.

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87 SE V6 Turbo

Screw the L67...

Hey Matt,
If you go with that (is it 282 getrag) ebay tranny, with the internal slave<<?
Could you take pics along the way, i am wanting to do the same(without the gear change)
Let me know what is involved.
Thanks

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88 GT, 3800SC, Getrag 5sp. 12" Vette Rotors,Custom stuff done

quote Originally posted by AutoTech: This bearing blew out. Guarantee you thats what happened.

I have had that happen before too, but it was coasting not under power. When I did that, I was able to drive the car home. This was not driveable. I loaded it on a trailer under it's own power, but it wasn't too happy.

Does anyone know what causes this shaft failure pushing into the bell housing?

I am currently doing a HTOB swap using a 94 sunbird bellhousing... but what goes around comes around revin

Thanks Matt. huh excuse me a sec, I have some trash to take out...

Dumb Horizon,
If you were the only one on here that showed a step by step, I would STILL not look at it or do anything the same as you! So don't even think you are hurting me in any way.... My car (and skills) are 20 times the car you could ever build or even SAY that you built!
So shove it big mouth! go race Archie or something, moron

I'm very interested in the autopsy of this box.

quote Originally posted by Matt Hawkins: Does anyone know what causes this shaft failure pushing into the bell housing?

My guess would be side-loading of the gears. Remember, the gear teeth are angled.

When the engine produces twice as much torque as the transmission can handle, all kinds of interesting things can happen.

Just out of curiosity, what type of flywheel and clutch are you using? And is the engine's rotating assembly balanced?

[This message has been edited by Blacktree (edited 06-25-2008).]

Would flywheel/engine situations really have any effect on the actual gears in the trans? Even in a small way?

LOL at revin!

quote Originally posted by darkhorizon: Would flywheel/engine situations really have any effect on the actual gears in the trans? Even in a small way? LOL at revin!

A heavier flywheel can increase the instantaneous loading quite a bit, so yes.

JazzMan

quote Originally posted by JazzMan: A heavier flywheel can increase the instantaneous loading quite a bit, so yes. JazzMan

Obviously it will increase load when your engaging a clutch, but this was in gear I dont quite agree.

I have an aluminum flywheel with a clutchnet six puck disc and factory pressure plate. The engine is internally balanced and I did nothing more to try to balance it.

I am interested to see what broke too. I am guessing that the shaft is poking into the bell housing, but I think the teeth on second gear broke first. The thrust load is going towards the steel end cap during drive torque. When the gear broke, it probably popped a hole in the bell housing.

My prevoius trans that had the shaft violate the bell housing was also in second gear at the time. But it was under a coast load. I still haven't taken that one apart, but will soon.

quote Originally posted by darkhorizon: Obviously it will increase load when your engaging a clutch, but this was in gear I dont quite agree.

Not all failures are instantaneous. Some slowly develop over time.

[This message has been edited by Blacktree (edited 06-25-2008).]

quote Originally posted by AutoTech: This bearing blew out. Guarantee you thats what happened.

I am starting to think this is the weak link. My theory is that you start getting stress cracks around this bearing. The coasting failures put a load on the shaft towards the bearing/cracks. This is what caused my previous failure. The new one must have just put too much force through the bearing area and let loose. Shearing the teeth off 2nd gear when it let go.

Does anyone know how much clearance there is with a typical clutch stack setup? Is there room to reinforce this bearing carrier? Maybe a girdle type brace?

Does anyone have a picture of this bearing failed? Bellhousing side and internal?

[This message has been edited by Matt Hawkins (edited 06-25-2008).]

quote Originally posted by Blacktree: My guess would be side-loading of the gears. Remember, the gear teeth are angled. When the engine produces twice as much torque as the transmission can handle, all kinds of interesting things can happen. Just out of curiosity, what type of flywheel and clutch are you using? And is the engine's rotating assembly balanced?

I don't think we have enough info to say either way.
For a helically cut reverse idler, for instance, both helix angle and pitch radius are the same at both "input" and "output", so the net side load on the reverse idler is zero.
The helix angles are cut such that the side loading on the output shaft from the shifted gears is in opposition to the side loading from the final drive. The side loading from the final drive pushes the output shaft AWAY from the bellhousing, not toward it.
@$$uming the same helix angle on the shifted gears and the final drive and because the output shaft has the same torque at all points along its length, then only variable that will change side loading is the pitch radius of the gear. First and Second output have a larger pitch radius than the pinion, so they will have smaller contributions to side loading than the final drive mesh and the NET force on the output shaft will still be AWAY from the bellhousing.

Driveline mass and MOUNTING has a lot more to do with transmission durability than most people think.

[This message has been edited by Will (edited 06-25-2008).]

I know a local kid had 2 bell housings with SIGNIFICANT wear from the clutch rubbing on that area.

Hey Matt, did you get your car back together?

Any pics of the actual damage to this tranny?