Help me w/ my 915 problem

[Lucky]

Sorry, this is a bit long -- thanks in advance for help!

I've got a shifting problem, which developed about 12 months ago. I'm sick of living with it and want to solve it before things get worse. Before fully describing the problem, let me tell you what I've done over the past 12 months in an effort to correct this:

• Replaced shift coupler bushings (old ones were fine)
• Swepco
• Replaced cup bushing at bottom of shifter (old one was worn)
• Replaced "donut" bushing in tunnel (old one was shot)
• Replaced motor and tranny mounts (engine mounts were worn but not terrible, tranny mounts were fine and had been replaced by the PO)

A big thanks to Pelican Marcesq for help with the mounts! He's a stand-up guy with AIR TOOLS!! Ooops, sorry Marc, maybe I shouldn't have said that... now you'll have all sorts of new "friends".

The above parts & lube didn't fix the problem, although the Swepco made shifting better overall.

The Problem...

The problem is the 3-4 shift. At certain RPMs it takes excessive effort to get the tranny out of 3rd and if I don't move the lever at the right (pretty quick) pace it takes 4th 5+ seconds to synchronize. The problem RPM range is from 3500 - 4000. Shifting below 3000 is OK (not great). Waiting until 5000+ shifts much better (and means I'm having a lot more fun!).

Shifts in and out of 1, 2, and 5 are silky smooth. Just the 3-4 shift is the problem. 2nd gear is a bit slow to synchronize (maybe that is related?).

I've also noticed that finding 4th can be vague at times -- that is, the gate for 4th doesn't always feel right.

What should I look at next?

The only thing I can think of looking at next is the guide fork mounted on the bottom cover. Is it likely that this fork would only cause problems with 3-4, or should all gears feel bad?

What else do I need to look at?

One more piece of information. Some syncros were replaced at 48k (car now has 77k) when the engine was out for new valve guides. I'll have to look through the records to find out which ones.

[targa911man]

John--

Sounds very similar to problem I had a few months ago, except mine was 2 and 5. I had a problem with the gates but also the synchros were bad, so I'm not sure what contributed to the problem more. Best to check the fork guide and gates first.

[Lucky]

Thanks, Dan.

How do you go about checking the gates? Can you inspect them without removing and disassembling the tranny?

[Adam]

I don't know about gates, but my 2.7's shifting problems (prior to the tranny rebuild) were slightly bent selector forks and very aged synchros.

[Lucky]

Adam,

Would you mind describing the symptoms you experienced... especially those that you think were related to the bent shift fork. Thanks... your experience may help me pinpoint the problem.

Anyone else have some thoughts? Any 915 wizards out there?

[Lucky]

Bump.