308 Gearbox Rust

Greetings,
I am in the process of disassembling a 1981 2Vi engine for inspection and re-build. The car history is pretty sketchy and without records, so I am trying to establish it's "true condition".
Inspection of the gearbox reveals some rust on a few of the gears. The visible bearings appear clean and rust free.
Searching the posts has resulted in very vague information regarding the impact of rusted gears....other than it is "not good" ...and even suggesting that the gearbox is essentially 'toast' with the presence of rust on the gear teeth.
I have attached photographs of what is typically visible with the gearbox intact.
Can anyone help me understand how bad this is, and if you have any recommendations of how to fix it.......a new one is not an option !!!
Thanks
Mike
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I'd run 'em just for the learning experience. Obviously disassemble and clean all the rust off by hand with a stone so you can see how deep the pits are and then monitor it ... frequently pull the magnets. Some of the teeth you might be able to see thru the drain plug.

If you absolutely only want to do it once replace them. I've got some good parts connections so PM me if you decide to go that route ... heck I'll give you trade in credit on that stuff.


cheers

 

I have seen it many times. Combination of not frequent enough gear oil changes and not cleaning out the vapor seperator. Usually but not always in a humid climate

Clean the gears and change any pitted bearings. It will be fine.

 

Where on earth is the vapor seperator, and how do you clean it out?

 

Part #1?
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Luckydynes / Rifledriver,
Thanks for the input. You are absolutely correct. The gear oil was like chocolate milk and the line to the oil separator was clogged.
I will clean the rust and give it a try.
BTW, any thoughts on the synchro condition from the picture? I don't have a good feel for what is "worn" out.
Regards,
Mike

 

Mike, i had my gearbox rebuilt recently.

Here's the link if it will help. http://74.86.28.138/~ferrari/forum/showthread.php?t=166826

Good luck.

 

Yup. Should be removed and cleaned regularly. When everything warms up it should allow vapors to be sucked into the motor and whole oil to drain back into sump. When clogged the water vapor doesn't have anywhere to go.

 

A couple of them don't look so good but often the tapered face on the gears is worn enough new syncros do not solve the problem. It is one of the long term costs of using cheap gear oils and not changing it often enough. I change it every year and we rebuild quite a few gear boxes, on new customers cars.....never old customers cars.

 

Remove it and soak in solvent. When they get rusty inside I put in a handful of small hardware and shake and flush until it flushes clean. Shake out the nuts and screws and reinstall.

 

Wow! Great tip. Thanks Brian.

I have to dig mine out while i'm on standbuy ($$$ ) and clean it.

So Solvent...... Paint thinner, Gas, Brake cleaner?

 

How does the engine oil seperator effect the gearbox? Is the gearbox vented over somewhere I havnt noticed?

Agree with everyone, clean off what you can (carefully) and run it. Paint thinner is generally mineral spirits (read the label to be sure) and mineral spirits is solvent.

 

Wow, thanks man. Do you do this every time you change out the gear oil?

 

Yeah it is ... there's a hose coming out of the bellhousing case near the drop gears ... since I changed to Swepco my oil seals on the diff started leaking ... was hoping it was due to excessive back pressure in that seperator so I unhooked the hose to see if that helps ... no .... guess that's a sign the oils getting in more places than the mud I was running .


cheers

 

thank god for simple european solutions The gearbox vent on my Euro GTB is just a hose coming from the bellhousing, fixed with a simple clamp at the oil cooler, the other end connected to.... nothing but fresh air
BTW; a good way to flood the gearbox with water when 'raging' with a steam cleaner.

Best Regards from Germany

Martin

 

You and Paul are both right. Not all cars have a hose from the GB breather to the vapor seperator. Some the GB breather is just a vent.

 

So the later cars vented the breather vent into the vapor seperator? Is this a better idea? Or was it more EPA BS to keep those vast clouds of gearbox oil vapor from killing the planet? Both my old antique gearboxes are clean and unrusty, for whatever thats worth.

 

Saved the Planet but didn't work out so well for all the infrequently driven cars out there. Bad enough allowing condensation to end up in the engine oil where there's a chance it might actually boil off on a drive. Adding it to the gearbox that rarely reaches a higher temperature is a formula for failure.

 

We have seen it in both types of gear box's. The venting going to the vapor seperator is a good idea and isn't causing trouble. Bad maint procedures are causing trouble. Letting the car sit for long periods cause trouble. People not knowing how the cars work causes trouble.

Old idea's dont make things better.....just old.

 

Brian, from the looks on the last pic, and on some of the gears, it looks like in only certain spots, like someone put it away, and left it for a long period of time where the water rose to the top and settled on the exposed parts only. Some of the others look somewhat more clean since in oil.

Like you profess: I am a big believer in changing the fluids every year. Also helps to get in those nooks and crannies every year for 'other' stuff.

BTW, I wouldn't run that without replacing all the bearings, just for safe running. Might not show rust/degradation, but with particles all about etc. those bearings seem like the weak link.

rik

 

Wouldn't the water in the gear box lube settle down to the bottom of the gearbox? As oil floats on top of water, therefore, the corroded parts would be the lowest parts. How would this situation work with synthetic lube?

 

Some of that moisture could be introduced from washing a bit too enthusiastically (and putting it away wet). I've had doors apart on cars that had never seen rain in 30 years but had rust in all the usual places.

I've told a few customers, "too much washing, not enough driving".

 

That is one of the reasons a vapor seperator is good for the trans. Without some source of vacuum sucking the vapors out instead just being "vented" the water present just forms a weather system in the trans. Yes, when static and cold the water will settle to the bottom when not in use but the water will only collect in the first place if the oil is changed infrequently, and the car is driven too little to get the gear oil hot enough to vaporize and be sucked out.

 

LMAO! I love it!