[FlyingBanana]

Hi, I had my (1969 GTJ) gearbox rebuilt with new synchros, bearings, etc by a well known UK Alfa gearbox specialist, but even after getting it back and using MT90, it has whined quite a lot. Recently, it seems to have developed a rattle when in neutral with the clutch out. The box has done less than 1000 miles since the rebuild, even though this was done around 5 years ago. I think I'm going to have to pull the trans and rebuild the box.

How do I identify if I have an early or late gearbox in terms of the bearing shopping list required as I understand there may be some differences?

Does anyone have a list of ALL the bearings required, along with part numbers? I'd prefer to use top spec bearings if possible to ensure this is a one off job.

If all new bearings are fitted, would there be anything else to then cause a whine similar to what is heard in a straight cut 'box?

I've checked the usual suspects like the boot/gaiter around the gear lever housing. The rattle increases with revs off idle and can be heard when driving (until road noise increases too much).

I would ship the box off to the specialist again, but I've lost faith in what they did given the hassle I'm now facing. The box was sent to them by another well known UK Alfa specialist on my behalf.

 

[divotandtralee]

Are you positive the "rattle" part is from inside the gearbox? It could be a worn Guibo or out of round which is kicking around the output shaft in the drive shaft coupling bush. Can you drive the car to the "specialist" who rebuilt it to demonstrate your problem ? Seems like the proper course to go even if a couple hundred miles.. The Redline synthetic oils are good about synchro action and perhaps whine and worth a try. I'm hearing the "rattle" as not part of bearing or assembly issues. Can't say I have ever experience whine out of a gear box.. Diff yes.

 

[Alfar7]

Well, Rattles are generally associated with the shifter mechanism in the tower, ot worn splines on the input shaft or the clutch disk. But you should check for loose attachments to the muffler.
Whine isn`t bearing related, but gear teeth not meshing properly. MT 90 is NOT the correct oil for the gearbox. Too thin. The correct lube for all Porsche design syncros is Redline 75-90 NS .

There`s threads on the bb about correct shimming of the shifter parts in the top of the rear tower. Do a search.
First get the MT 90 out and put in 3 pints of the Redline NS. Too thin lube might be the whine you hear.

 

[ossodiseppia]

The recommended lubricant for the vintage Alfa is 90 WT, not a multi weight.

 

[divotandtralee]

.. not to be confused with Dentax [Straight 90 not EP (extreme pressurer)] on the "earlier earlier" boxes from 750's and 101's.. just for TMI purposes

 

[FlyingBanana]

Well, Rattles are generally associated with the shifter mechanism in the tower, ot worn splines on the input shaft or the clutch disk. But you should check for loose attachments to the muffler.
Whine isn`t bearing related, but gear teeth not meshing properly. MT 90 is NOT the correct oil for the gearbox. Too thin. The correct lube for all Porsche design syncros is Redline 75-90 NS .

There`s threads on the bb about correct shimming of the shifter parts in the top of the rear tower. Do a search.
First get the MT 90 out and put in 3 pints of the Redline NS. Too thin lube might be the whine you hear.

Hi Richard,

Apologies, I had brain fog, I am using the NS version of the redline 75-90 oil (not MT90). I'll take a look at the recommendations posted in the thread so far, and report back. I may try and get a recording of the noise.

thanks all.

 

[divotandtralee]

"I had brain fog " Does this mean you went "bananas" ?

 

[Alex]

I have a very comprehensive list of bearing numbers for early 191/105 and late 105/115 gearboxes, including a big stash of 'the real deal' NOS bearings and other major internal components. Send me a PM if you're interested. Based about an hour north of London. I can also give you the names of a couple of really good transmission specialists.