Can't Shift

[Hugh R]

Driving home from by Brother-in-Laws the car started shifting really, really bad. Couldn't get 2nd gear at all, balky. I had to speed shift 1st to 3rd. Replaced all the shift bushings per Wayne's book about 3 years/25,000 miles ago. Can the shift rods move and un-adjust like that? Checked underneath, and no dropped trannie mount bolts. Adjusted the clutch last December, about 5K miles ago. I'll readjust the shifter tomorrow night, any other thoughts?

[dentist90]

In the case of my car it was broken teeth on the synchro hub on 2nd gear. This allows the synchro ring to 'pop' out a bit, which increases it's circumference and the shifter sleeve can't slide over it. If you haven't lately, it may be time to drain the tranny fluid and see if any chunks come out. This is what I mean...


These came off of this...

[Formerly Steve Wilkinson]

Try readjusting/re-zeroing your shifter linkage, under the plate at the aft end of the center tunnel. I had mine go out of adjustment at about 10,000 miles on it, couldn't get fifth.

[Hugh R]

Thanks, Dentist, I sure hope that isn't it. Thanks Steve! I'll play with it tonight.

[}{arlequin]

try the clutch cable adjustment again. about 6 wrech rotations, not full 360 deg shoud tell you whether it made a difference or not. 5k miles could be enough to get it a bit out of spec... is your clutch cable 'double nutted' under the car? if not it does slip a bit eventually....

[Formerly Steve Wilkinson]

What Harlequin means by "wrench rotations," in case it isn't clear, is "nut flats"--i.e. put a box wrench on the nut, turn it enough that you can get the wrench on the next set of "flats" and do that six times, which should total one full rotation of the nut, though he's saying to do it slightly less than one full rotation.

[}{arlequin]

correct. thanks for clarifying.

[Hugh R]

I'll try both, thanks

[JP911]

Could be a failed pilot bearing.

[Hugh R]

God I hope not! I've already got another car completely torn apart as it is.

[JP911]

Perhaps a failure in the clutch throwout mechanism (arm, bearing, etc.)? How does the clutch pedal feel?

[Icemaster]

I'm betting shift linkage coming loose, this has happened to me as well, feard the worst, hoped for the best and got lucky with re-adjusting. ABout the same interval after doing the full bushing replacement.

[rcecale]

Originally posted by dentist90
In the case of my car it was broken teeth on the synchro hub on 2nd gear. This allows the synchro ring to 'pop' out a bit, which increases it's circumference and the shifter sleeve can't slide over it. If you haven't lately, it may be time to drain the tranny fluid and see if any chunks come out. This is what I mean...

Well, Leatherneck, I truly hope this is not the case.

Here's the thread from a couple of years ago when this exact thing happened to me.

I learned a lot about my car during this evolution, as is readily apparent.

Semper fi!

Randy

[dentist90]

The thing that occurs to me is that Hugh is describing one balking gear (2nd) but that the others presumably work OK. The clutch must be working OK if he can engage 1st, then shift over into 3rd smoothly. Is it correct to asume that all other gears are engaging properly?
I realize that if a shift coupler goes out of adjustment one can have trouble with 5th, yet still be able to grab reverse. If Hugh can engage 1st but not 2nd, which are in the same plane and share the same the same selector rod, it suggests to me that something is wrong internally. Perhaps the guide fork inside the inspection plate is coming loose and preventing proper movement of the shift fork(s)? I would expect that to have an affect on 4th as well, though. Do let us know what you find!

[dentist90]

You can see from this picture how much more interference there is on the synchro ring near the missing teeth. Quite often I couldn't get the darn thing into 2nd at all, other times it would go in with a bit of resistance with subsequent attempts. Notice the shiny worn area on the synchro ring to the right of the missing teeth...

This is where the sliding gear was getting blocked from smoothly sliding over the synchro ring.

PS: Randy (RCECALE)! Your thread was one of the few that gave me the information and confidence (courage?) to do this rebuild on my own. Thanks for all the quality photos you posted along the way. man! I've also spoken to JW on the phone briefly... what a helpful guy! Gotta watch those detents!!

[Hugh R]

Shifter Adjustment!!!!!!!!! Thanks everyone. With the British trash in pieces, pulling and rebuilding the trannie was the last thing I needed.

Dentist, it started acting up on the way home from the exBrother-in-laws and I knew it wasn't the couple of beers. I pulled it from 1st into 2nd and the shifter went way deep into where 2nd should be and it wasn't there, so I went back to first and wound it up and short shifted into third. He only lives a mile or so away so I never got 4th or 5th, and backing into the driveway it went into reverse, but all gears felt like I was over shifting. Anyway, I'm delighted. You guys are the best when it comes to support. I posted an oil pump question on the Aston Martin BBS two weeks ago, and have yet to get a response.

[dentist90]

Whew... I wish I had your luck. Happy endings are nice.
That last bit of info makes a world of difference. My balky shifter was tight, try to move it from N into 2 and the shifter wouldn't move any further. All other gears are tickety-boo.
Sooo... what's wrong with the ol' oil pump anyway?

[Aerkuld]

Originally posted by dentist90

Sooo... what's wrong with the ol' oil pump anyway?

Hugh R,
I was going to say the same after reading your post.
I really enjoy the community here, I'm sure we can figure out Aston's problems between us.

[Hugh R]

You know, I think I will, but not on this thread. I'll post a separate thread on the subject just to keep it on target, in PPOT. I get little response on nitty gritty Aston issues from the AMOC website. In fact, I posted an earlier thread on pulling the motor (I think entitled "pulled the DB4 Motor" but I'm not sure, and I'll add to tomorrow if I can. British vs. German "Engineering" are very different animals, especially if your talking about a 1950's/60's vehicle. Thanks again guys.

[Formerly Steve Wilkinson]

Been 40 years since I pulled a DB4 engine, but I remember it well...