1967 4 th gear popping out

[lfausty]

cant get 4th gear to stay in , shifter and trans linkage bushing new.

ive done every length and side to side all gears shift fine and no slop but 4th gets there and wont stay in. thanks

[WFBowen]

Did this happen recently or since you've owned the car? Is it on rough roads or bumps or just any time?

[Flieger]

Did you adjust the coupler position?

If that is good, it sounds like a worn 4th gear engagement slider (part that goes over the synchro friction ring). When the little groove wears too much, there is no "lock".

[lfausty]

wfbowen its anytime just got temp tag to put on road after over yr restoring, in running it through its gears to see what i got for trans. the slope and slack: purchased shifter bushings and the trans adjustment linkage purchased new bushings.

but a bit of trial and error adjusting after adjusting procedure done still no 4. it is grinding to get into 4th gently can get into 4th but doesnt seem to fully engage or lock in. THANKS

Any help on this before have to move onto flieger posting worn 4th.

[WFBowen]

lfausty :
I'm certainly no gearbox expert, but I think flieger's post is the route to follow - you seem to have done all of the possible adjustments so it's probably not a linkage issue, especially with grinding going into 4th.
Good luck,
Bill.

[lfausty]

roger that - winter project was going to be paint but one more yr itll have to stay in ghetto primer, ill just bow my head in shame and motor on. lol

trans is 901-801-101-0R i can keep a look out for cheap parts car , or the couple new parts....

would this trans be one that needs new gaskets inside when rebuild, seem to find newer yrs that take a kit , and would there be 911-912-914s that have compatabile trannys, this would be tail shifter? where there is also side shifter?

[Flieger]

Where are you located? We might be able to recommend a good mechanic.

[lfausty]

a good mechanic,for what? , what you know one that buys u the parts!!!. lol or one that can scrub the parts no. to see what they are, 901- 8?01(301 maybe) looking at numbers on parts diagrams for orig 67 tranny i could have them incorrect or this could be from who knows what yr/model porsche but that it is compatible. i dont have every manual only the 912 info. can be unfortunate if some 914,911 stare me in the face and could use and i dont know in a split second if would work. can i modify and fabricate anything , yes but id need at least to get close info , something to work with.

im in north country NH.

[Matt Monson]

lfausty,
Every Porsche gearbox from 64-71 911, 64-69 912, and 69-76 914 are 901 based. The parts inside are pretty interchangeable. But what you want for your car is a 1964-1968 aluminum case 901 or 902 type gearbox. That's the direct replacement without having to tear it apart and move parts from one case to the other.

Is your car a 4spd or 5spd? I'm kind of guessing 4 speed from your issues? If so, I may have a gearbox that would work for you.

However, if you've got the mechanical ability and the time to put into it, repairing your gearbox can be done without spending too much money on parts. If you want to do a "just keep it on the road" service used parts within spec are really cheap and easy to come up with. If you go with all new parts for the ones you have worn out, it will be $300-400.

Though beware the slippery slope. There's the temptation to do it the "right" way and totally rebuild it. The "while you're in there" items start to add up really quickly. You have to be ready for that and the dangers of your own mind once you get it apart and start the project.

Provide a little more input on what you think you want to do here, and I am happy to help guide you through whatever process is going to work for you.

[Flieger]

I meant a mechanic who has lots of experience and does good work but does not charge as much as most shops would.

[lfausty]

matt thanks car is 5 speed, not going to overhaul trans just fix whats needed for 4th, and any other parts that arent in spec.
slider gear for 4th can be repaired in car? or does it need to be on the bench.

whats all needed for a fix, its going in but not locking in like all other gears. BIG thanks

[Flieger]

The trans needs to come all apart on a bench for the 4th gear slider. It is the part the brass shift fork on the rod moves to engage the dog teeth. What is the problem could be that the synchro friction band has worn down to be too small an outside diameter and does not lock into the groove in the slider. If the synchro is worn, it will also not snychronise the dog teeth speeds fast enough to make a gearchange without crunching. The inside diameter of the silder wears with the snychro band and the groove in the middle that allows the ring to expand and lock into gear will get too shallow and not do its job. This was happening to my second gear when my trans was opened to fix the broken 4th.

[lfausty]

thanks F i got what to do then, great(sarcastic) eng have to come out? Ill ask for second and more opinions, but, i dont want any and your feet smell too. lol.

when this particular 901 trans comes out and apart do you need gasket/s / kit upon reassembly. and will i get through job with tools or is there a must for special tool .....for any part to come off.

[Rusty 356]

fausty, there is a stretch bolt that is rather deep that will need to come off. Also, when you are taking intermediate plate and all the gear out, document the thickness of the gaskets between the intermediate plate and trans housing and replace with same thickness. Good luck. I had a similar problem with my 912, it had really stiff KYB rears which knocked me out of 4th . Changed to Boge and problem cured. Your's sounds like a different cause.
I recently rebuilt a 356 gear box and installed new sliders and syncros at the cost of 2K for those parts.
Good luck,

[lfausty]

The day i have stiff kyb to upgrade to boge... will be sweet for me im riding the rails,yeehoo.

will do stretch bolt........... tankx