Alfa Romeo Forums banner

21 - 30 of 30 Posts

·
Registered
Joined
·
74 Posts
People get in trouble on shims when the shims STICK to a surface on disassembly and then fall off on the bench the next day.. then ...""where did that come from?"
Looks like you've been to my workshop when I have been dissasembling the gearbox. :)
 

·
Registered
Joined
·
74 Posts
Hi,

so, I checked the shimming and it turns out it was not centred properly - also not far off, so 3/4 could be shifted straight still.

After playing with my available shims, I think I got it right and now it shifts nicely through all gears and out of 5th as well - with and without retainer plate. It’s actually pretty simple to adjust once it is understood how it works :)
Thank you for starting the thread. Looks like we are in a quite similar situation. I have finally put together my gearbox on Saturday and it shifts nice on the bench. Only the fifth was really hard to engage and disengage. Has improved after several tries but still harder than all the other gears. Also reverse shifts nicely. On the other hand I have dissambled the fifth and changing the gear as well as synchro rings.

Anyway I completely got the point of centering the shifting rod wrong! Will have a look again how it sits inside.

Moreover good idea of using some grease on the rods and shims. Can't heart.
 

·
Registered
Joined
·
4,545 Posts
On an early trans with a bushed 5th, if it is difficult to engage "dynamically" (i.e. in the car) I would suspect excess rocking/radial play as well. Those bushes are commonly worn. The later bearing-supported versions do not seem to suffer the same fate.
The synchros work best when engaged squarely. Rocking or misalignment reduces this engagement potential.
 

·
Premium Member
Joined
·
6,385 Posts
I'll add that 1, 2 and 3 are bushed as well, and wear in those bushes can lead to off-axis loading when the slider is trying to engage, making engagement more difficult, as well as the overall slop and loss of crispness in the box. I always change those bushes if they are too sloppy -- and I am well aware of the difficulty in getting the new bushes machined and trued. Dont make first gear bush too tight!!! ANY misalignment in machining in those bushes is a recipe for problems.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #26 ·
Today was the big day I drove the car for the fist time - did not go so well :D

First I was not able to shift into 5th at all and it got stuck in reverse until I, for whatever reason, could disengage it without force... so I drove back home using 1st to 4th. After having reversed into the garage, I could also shift 5th again and it got easier after doing it a couple of times... so then I drove it again and now 5th engages easily but immediately pops out of gear if I step the slightest bit on the throttle.

I‘m a bit puzzled by this to be honest. On the bench, everything was fine and carefully adjusted. After mounting it on the car, it was a bit more difficult to shift but ok... and now driving it is something else again.

If I understood it correctly, jumping out of 5th should be related to the shimming of the gear lever? ... or at least this would be the first thing to look at, correct?
 

·
Registered
Joined
·
9,131 Posts
Does your car have a center console..?? Sometimes the outer leather gaiter combined with weak motor mounts will create forces back to center neutral on the shifter in REV and 5th
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #28 ·
My GT1300 Junior does only have the rubber / leather boots. I removed those and went for a drive - same problem.

When holding 5th in engaged position, I believe I can feel through the lever, that the sleeve is grinding on the fork - the lever itself can be pushed to fully engaged position.
I‘ve replaced the shift fork with a reproduction one ... probably not the best idea... so I will go and pull the transmission out again and check.
 

·
Richard Jemison
Joined
·
8,019 Posts
Check the balls and springs in the rod Detent holders at the top front of the case.
 

·
Registered
Joined
·
26 Posts
Discussion Starter · #30 ·
Opening the rear cover again, I found two things:

1. The outer race of the rear mainshaft bearing moved forwards and got in contact with the 5th gear. Well, it does not have the axial limiting step on the outer race, but it is the *** bearing with the same number N205 - just sold today... and a lot cheaper than the original style ones sold by the parts dealers, I just ordered to solve this problem. To be safe, I‘ll also add some Loctite to keep the outer race in position.

2. The repro shift fork for 5th and reverse seems not to be straight. In fairness, I only checked the 12.9mm at the top and assumed it to be straight... well... the old one worked before, so it will go in there again.

Can anyone confirm measuring the 12.9mm as shown below is correct? It’s not pretty well described in the manuals... and is it actually 12.9mm when the sleeve is pushed to it‘s most rear- or forward position within the tolerance of the fork?

The bearing balls, springs and grooves on the rod I‘ve checked and found to be ok.

3099BFFA-E093-496A-AF40-4B7E5E121D7A.jpeg


229EB77A-43F4-4565-9559-F7E93381F5B6.jpeg


1686274


1686275


1686276
 
21 - 30 of 30 Posts
Top