Stripped speedo drive locator bolt thread, New question: what's up with my firewall shift bushing? Options

[john77]

Not a great evening working on my car. I got the car up on stands and drained the tranny in preparation for resealing the speedo drive, side console and diff shafts before installing the tangerine linkage and firewall bushing.

First thing I did was remove the old speedo drive to fit the new double sealed one I got from 914rubber only to find the shaft down the centre of the new one wasn't big enough to fit the gear??? So I put the old one back in, didn't match up the hole in the drive to the hole in the case correctly, over-tightened the bolt thinking it was going into the hole and stripped the thread out. Seems like such a bad design, or is there some kind of mark I missed that let's you know the hole in the drive is matched up with the hole in the case?

Not really sure what to do now. Is their anyway to fix it that doesn't involve pulling the tranny? Off the top of my head all I could think of was swapping out the entire rear plate with the mount arms for another one. Or taking off my muffler (ugh) and threading a new larger hole, which will then require me to machine a new, larger locating bolt. Or, as it's not a structural bolt, just JB welding that sucker back in, but then I'd be joining the legion of DAPOs, which was never one of my aims in life.

The piece I got from 914rubber doesn't even have a hole for the bolt end to seat in, but that bolt has to hold it in there somehow right, or else what the hell stops it from falling out? I have to drink beer.

[Mike Bellis]

Pull just the tail cone and install a time-sert. easy!
http://www.amazon.com/TIME-SERT-Metric-Thr...words=time-sert

[john77]

Pull just the tail cone and install a time-sert. easy!
http://www.amazon.com/TIME-SERT-Metric-Thr...words=time-sert

Ooo, nice, thanks Mike. Can I unbolt the transmission mounts and the tail cone and leave the rest of the tranny still mounted to the engine in the car?

[Mikey914]

Helicoil would do the trick too.

The only thing I can think happened here is that you got a reject by mistake. There is a mounting hole in the finished units. The tolerances we have on this are so tight that we have to de burr the end to make it fit. So, de burring didn't happen on this one. I suspect that it is not a finished unit. I'll get you a correct one out Monday.

Sorry,
Mark

[SLITS]

Ooo, nice, thanks Mike. Can I unbolt the transmission mounts and the tail cone and leave the rest of the tranny still mounted to the engine in the car?

Yes .... drain the tranny first though!

[Harpo]

Mine already ha a helicoil. I had assumed it came from Porsche that was because of the magnesium case.

DAvid

[brant]

I installed a heli coil in one nearly 20 years ago

Pretty sure I did not have to pull the tail cover or anything.

[Mikey914]

No Helicoil is acceptable because of the loads required. The bolt is to only to lock the part in place.

[injunmort]

before pulling tail cone jack up the trans a little and support it with a jackstand so the whole lump is not hanging by the front motor mounts.

[Harpo]

No Helicoil is acceptable because of the loads required. The bolt is to only to lock the part in place.

I'm confused by your statement Mark

Helicoils are used every day in high loaded application. If the helicoil is installed properly it can be just as strong if not stronger than the original joint. I agree that this is a low load application though.

[brant]

I've had a heli coil last for decades.
When it fails I guess I could do more

[Mikey914]

No Helicoil is acceptable because of the loads required. The bolt is to only to lock the part in place.

I'm confused by your statement Mark

Helicoils are used every day in high loaded application. If the helicoil is installed properly it can be just as strong if not stronger than the original joint. I agree that this is a low load application though.

Not saying that Helicoil is a weak product, both are overkill for this application. Timecerts are as good at the original material. That being said, I've used way more helicoils.

[john77]

Helicoil would do the trick too.

The only thing I can think happened here is that you got a reject by mistake. There is a mounting hole in the finished units. The tolerances we have on this are so tight that we have to de burr the end to make it fit. So, de burring didn't happen on this one. I suspect that it is not a finished unit. I'll get you a correct one out Monday.

Sorry,
Mark

No worries, Mark, it happens. I managed to thread this and round out the wayyy over-torqued bottom drain plug, so my car won't be going anywhere until I fix the former and the a new plug arrives from pelican anyway.

The only reason I thought I might need to pull the end off the trans is that there's simply no room to work in there because of my muffler - there's maybe two inches between it and the end of the trans, so too tight for a drill bit or a tap. In the cold late of day/calm it'll be much easier just to pull my muffler.

Given that the bolt's only job is to hold the drive in place, I'll probably just put in a less expensive helicoil with red loctite.

In the meantime I'll be doing the tangerine linkage and bushing today. So stand by for more panicked posts when I screw something else up... (IMG:style_emoticons/default/smile.gif)

[john77]

Okay, that didn't take long. Is this outer flange stock for the shifter firewall bushing? I was going to fit the tangerine bushing but the hole the shift rod goes through is completely off centre and the flange prevents it from sitting flush against the firewall.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i2.photobucket.com-17027-1439063314.1.jpg)

[Mikey914]

Okay, that didn't take long. Is this outer flange stock for the shifter firewall bushing? I was going to fit the tangerine bushing but the hole the shift rod goes through is completely off centre and the flange prevents it from sitting flush against the firewall.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i2.photobucket.com-17027-1439063314.1.jpg)

Yes it is stock. The lips there as you probably noticed cover the assembly with a bellows. I wouldn't want to eliminate it, as it actually caught the tapered screw that holds the linkage together, so that on the side of the road I found it and was able to get it screwed back in when it had backed out.

[john77]

Okay, that didn't take long. Is this outer flange stock for the shifter firewall bushing? I was going to fit the tangerine bushing but the hole the shift rod goes through is completely off centre and the flange prevents it from sitting flush against the firewall.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i2.photobucket.com-17027-1439063314.1.jpg)

Yes it is stock. The lips there as you probably noticed cover the assembly with a bellows. I wouldn't want to eliminate it, as it actually caught the tapered screw that holds the linkage together, so that on the side of the road I found it and was able to get it screwed back in when it had backed out.

Thanks Mark. Guess I'll just stick with the stock bushing.

[Mikey914]

Okay, that didn't take long. Is this outer flange stock for the shifter firewall bushing? I was going to fit the tangerine bushing but the hole the shift rod goes through is completely off centre and the flange prevents it from sitting flush against the firewall.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i2.photobucket.com-17027-1439063314.1.jpg)

Yes it is stock. The lips there as you probably noticed cover the assembly with a bellows. I wouldn't want to eliminate it, as it actually caught the tapered screw that holds the linkage together, so that on the side of the road I found it and was able to get it screwed back in when it had backed out.

Thanks Mark. Guess I'll just stick with the stock bushing.

Pretty sure Pelican has them too.

[john77]

If I keep this up I may need my very own face palm emoticon. I spoke to Chris at tangerine and he pointed out something that should have been obvious if my brain wasn't so small - once I remove the factory bushing the hole will be bigger, so I should be able to reposition the tangerine bushing inside the flange and still have clearance for the shift rod...