Weld or replace?

[steven12xu]

Hi. I couldn’t get my ‘86 Carrera to turn over with the key on Friday. I rolled it off in reverse and it laid this jagged little egg on the driveway.




It’s a piece of transmission bell housing from the bottom on the sensor side. The bolt through the cases is still there. Another loose bolt has pretty much destroyed the starter ring teeth and is hanging out the bottom of the case where it’s blown another hole.
My mechanic thinks this piece can be welded back on.
Since it has one of the main bolts going through it, would I not be better off replacing the front section of the case? Long term reliability is more important than a cheaper repair. Thanks

[Flat6pac]

Looks like the bell housing bolt wasn’t there to begin with
Something had to be loose inside to disrupt and force out to break the piece.
Got to pull the motor to find out what other damage may be there
ie, loose clutch cover bolts.
Bruce

[Harpo]

While I do believe that a skilled welder can weld it back on the bigger question is what caused it.

[yelcab1]

I would try we-welding by a good TIG welder. The alternative of replacing the bell housing is akin to a total gearbox rebuild. This looks expensive.

[911obgyn]

A good welder can repair it, ask if they will pre heat the metal, it’s an important step to reduce crystalizing the metal around the weld.

[steven12xu]

I just got back underneath and took some flash pictures. The piece is from the bottom side of the case and the connecting bolt is still in.

Here is the broken case and the projectile through the other side beneath the new starter. Anybody recognize it in its mangled state?
It looks less bad now knowing the cases are securely together.

[dannobee]

Like Bruce said, you're going to have to pull the engine and transmission to assess the damage.

It appears that the clutch cover bolts were left loose and backed out.

If you have all of the broken parts, it could be TIG welded back together, but I don't envy the welder by any means. He's going to have quite the job getting all of that stuff clean enough to weld.

[stownsen914]

Yeah, something came loose in there, wedged itself, and broke the case .

Obviously, don't start the engine (or even turn it over with the starter) since we're not sure what might still be in there hitting things. Next step is to drop the engine and separate the trans, and see what's damaged.

Welding magnesium can be done, but I'd be a little concerned about it holding up since that area of the trans is structurally important. Magnesium weldments are not known to be the strongest.

[steven12xu]

Thanks everybody. I’m worried about the sliver holding that bolt, too. I was going to have the transmission done later after the suspension and a/c. It looks like that order has changed. The starter had been grinding for a while. Now I know why.
It’s magnesium on an ‘86?

[Dpmulvan]

Originally Posted by stownsen914

Yeah, something came loose in there, wedged itself, and broke the case .

Obviously, don't start the engine (or even turn it over with the starter) since we're not sure what might still be in there hitting things. Next step is to drop the engine and separate the trans, and see what's damaged.

Welding magnesium can be done, but I'd be a little concerned about it holding up since that area of the trans is structurally important. Magnesium weldments are not known to be the strongest.

Car is an 86 should be aluminum not magnesium.

[proporsche]

to me ,it looks like the starter gear fell off and was traveling between the pressure plate and the bell housing while you pushed the car, this happened...take it out and inspect..

Ivan

[Mike Andrew]

Tough choice - weld or replace. I saw many aluminum castings weld repaired during my aero mfg. career but it takes a good shop with the correct gear including inspection equipment to verify weld integrity. It will also likely require some post weld machining to clean things up.
Once you have things on a bench you may find additional damage that precludes this option. I would make the rounds of the salvage folks - DC Auto, LA Dismantlers, Einmalig and see how much Is involved for a used replacement. This would be my choice for peace of mind.

[steven12xu]

Thanks. I’ll check the dismantles. There’s a bell housing case locally for $750 and one on eBay for $365. The car is off to my mechanic’s this week. Thanks for all the messages.

[pmax]

Originally Posted by steven12xu

Thanks everybody. I’m worried about the sliver holding that bolt, too. I was going to have the transmission done later after the suspension and a/c. It looks like that order has changed. The starter had been grinding for a while. Now I know why.
It’s magnesium on an ‘86?

Looks like the starter has been grinding on more than just the ring.



What kind of starter is that ?
I notice similar damages on the bolts here starter ring failure twice in 3 weeks. HELP!!.

[steven12xu]

I installed a new Bosch starter identical to the one I took out. It’s been 32,000 miles since the engine was rebuilt. The clutch was relatively new when I bought the car about twelve years ago. It’s got about 40k on it. I don’t think the engine/trans has been apart since the engine rebuild. The starter started grinding late autumn and sat all winter until I could fool with it.
Whatever the projectile is must have a head on it because it’s loose through hole but won’t pull through. I’ll post again when the engine’s out and I know what’s going on.

[pmax]

Yes, please post the findings and root cause. I also see marks on your pressure plate so I guess one of the bolt heads gotten free sheared off from the grinding and has been crashing around in there.

[cabmandone]

Where are you located? I'm going to be selling a core 915 that needs 1/2 refreshed. 3/4/5 are butter. I have two videos on here of how it shifts now. I'm hoping to have this done in July. Don't know how long you want to go without your car though. The only question mark will be how the bearing races will be. It's the older 915 with the larger bearings that can have issues with the races coming loose in the housing.

Looks like in the pics you're gonna need a new ring gear too.

[steven12xu]

I’m in Ellijay, Ga. The car is going in this week. I’ll know more in a few days. I’ve found a case and a rebuilt transmission locally but they’re overpriced and I’ve been tooled by the guy before. My mechanic is very, very good. We’ll see.

[911pcars]

If prepped and welded professionally and bolted to an engine case “jig” for alignment and fit,
, should be fine. Good welds are typically stronger than the base metal. Separate the drivetrain and let us take a look at the other damage.

Sherwood

[steven12xu]

My regular mechanic is in the process of moving to a new location. Any suggestions on a shop between north Atlanta and Chattanooga who can work on my transmission? I’ve tried three and have gotten no response.