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Transmissions ain't so tough!


Tim Comeau

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In an effort to further educate myself about our cars, John Chambers and I tore down my dead tranny yesterday. The biggest problem for the lay person would be having all the right tools.

We cannabalized my dead tranny's 3rd gear synchro and hopefully that's all he needs to get his new white 944 on line. It was popping out of 3rd gear. We thought the tranny suffered from a broken ring gear because it would click at the same point in different gears. Turns out that teeth from 3rd and 2nd gear had broken off (not sure of the sequence of events) and worked their way back to the ring gear, then got jammed in there.

We think we know why my red car's tranny has a loose output shaft bearing. Lack of pre-load shims behind that "cup" bearing. We'll get it.

Let you know.

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No doubt the NA transmissions are heavily flawed in regards to tough durability. Especially the ring and pinion! As usual every track day will be a prayer and miracle if mine doesn't let go...

 

Good luck on your investigation Tim!

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Welcome to the class Andy!

You'll have a blast in this class. Please take the time to read our rules. They're simple, but they are changing some for 2005. Mostly to clear some things up and be more helpful.

 

Regarding the trannys, I don't think they're weak. And we're not putting any more hp through them, just more continuously now.

The ring and pinion in our 944's looks to be more than adequate. I believe the biggest problem is:

1. driving them into the ground.

2. not assembling them PROPERLY.

There are measurements along the way. There are different thicknesses of locking rings, circlips, and shims. If you don't do it right, you'll get a tranny than whines and has a shorter life span of its bearings. Especially the pinion bearings.

It isn't rocket science, you just have to have the right tools or suitable substitutes, and the desire to do it right. Read the factory manuals. They're cool as hell!

BTW, so far in my red car's tranny, we've found the Pinion shaft wasn't properly seated. It had about 2mm play side to side! This drastically affects how the ring and pinion mesh. That was the reason for the teardown.

We also found one of the locks for the synchro/gear/slider sleeve had come out! Probably due to premature movement of that gear's selector rod before the gear assy was put back into the gear carrier assy, or the 5th gear wasn't assembled at the right time.

Anyway, the little lock met an ugly end.........its guts and bone fragments were stuck to the magnets, which is what Porsche put them there for.

So, my silver 924S has a complete tranny with tall 5th.

My red 944's tranny is reassembled with an LSD and short fifth.

John Chamber's white 944 has a working tranny once again.

I hope to do some more trannys in the next few weeks.

 

At your service,

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Yeah,

I agree with Tim.

These tranny's are pretty good for racing. I have seen only 1 944-spec tranny failure. Maybe even the only tranny problem. Given that 90% of these cars started as junk cars on their way to the scrap heap I think they have held up very well. I would not recommend anyone worry about the gearbox. Better to worry about keep the oil in the engine for the numbe #2.

 

In 2 years of racing that seems to be the only racing weakness. Sure other parts fail, but those are mostly little stuff due to the age and lack of care from previous owners. But what you do expect from 16-21 year old car that mostly had been written off for dead.

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