Check this out corrosion after 4 days

[Alex Mckenzie]

Hi all
I rebuild my 020 gearbox last week but looks like I used the wrong input seal so had to pull it out again, anyway I pulled the 5th gear cover off and this is what I found.

Corrosion of the gear. Alarmed at this I dug deeper and found
More corrosion, all the gears have been affected and to a lesser degree other parts.
If put nulon sae 80 api GL4 in the gearbox on Tuesday, and the above is what I found today. How can this be?
I believe the is the right oil to use, am I wrong?

Any thoughts? Best recommended remedy to clean it all ?

[ryana89]

Try wiping/scrubbing it off with some kero (may have to let it soak).
Do you think condensation could have build up? That's weird.

[roccodingo]

Looks to have been assembled dry, also note overuse of silicon sealant on jointing faces.
As the silicon cures some types express acetic acid ( from memory ) which can basically acid etch bare steel, likely making it more succeptible to moisture attack.

If the seal was leaking oil out it will certainly allow the passage of crap in. Had you washed it with water / degreaser to remove the oil leakage before disassembly ??

Go buy a tube of VW jointing paste for the trans reassembly .

[Alex Mckenzie]

Do you think the oil may be the issue? Should I chuck it use different oil?
Any recommendations on oil? I can't find the redline product which people recommend. I've used cast roll vmx80 in the past, I wanted to try something diffrent thence the nulon. The api gl 4 oil isn't that easy to find

[wai]

Looks to have been assembled dry, also note overuse of silicon sealant on jointing faces.
As the silicon cures some types express acetic acid ( from memory ) which can basically acid etch bare steel, likely making it more succeptible to moisture attack

Yes, there are two types of silicone sealant. Acid Cure (acetic acid), and Neutral Cure (ammonia). You need to be careful with acid cure as it can damage components. I used to use silicone sealant on my radiator hoses on my old Torana after a mechanic recommended it. The problem was that if some of the raw sealant got into the radiator, the acetic acid would end up corroding the radiator tank soldered joints.

Whatever sealant you use, more is not necessarily better. Bits can break off and end up in galleries or pumps or bearings.

On assembling the gearbox (or any engine transmission unit), you should always use assembly lube. It is heavier and more clingy than regular engine/transmission fluid, and protects surfaces for that critical first start, and until the normal lubricant has a chance to coat all surfaces properly.

[Alex Mckenzie]

Thanks for the info I'll take note on thr. Do you think the oil will now be contaminated or should it still be good to use?

[Transporter]

The oil is the least of your worry. I'd be concerned about the condition of the bearings and the gears. Change the oil and put some extra additive in as well. I suggest the Nulon G70 or Moly 2.5

[Jmac]

Oh dear never ever seen that. Way too much sealant there mate, only needs 2mm bead, id use wurth sealant and not that horrible stuff there. Also id recommened Fuchs synthetic oil in that box, just saying
Cheers
Jmac

[Alex Mckenzie]

So looks like the consensus is I used a stupid amount of sealant, left it dry for a few days before adding the oil, allowing the sealant curing process to start eating way at the metal in the gear box?

Thanks all for the advise, I bow my head in shame, consider me scolded and hopefully educated.

Cross fingers the mighty 020 can recover from this abuse or it's off the the wreaking yard to try and find another gearbox. mk2 is out of the question in Brisbane so a mk3 gearbox will have to do.

[wai]

Not necessarily a new gearbox. If you have the time and are prepared to do the disassembly and reassembly, you could basically do an overhaul.

[Alex Mckenzie]

Already stripped cleaned soaked, cleaned, although the some of the surfaces are etched / rough, I can only assume no,good will come from this, I'll take the parts to a gearbox reconditioner and see what they say

[wai]

Fair enough. The thing about a secondhand unit is that it is also a bit of a chance on its condition as well.

[brad]

Were all the parts coated in oil or similar before assebling the gearbox? Or was it all squeaky clean dry?

[sports racer]

Do you know how hard it is to kill a gearbox?

So you've got a poofteenth of surface corrosion on some of the gears, so what.

Clean off the red crap, put on new sealer - about 1/10th of what you did before, put it back together and fill with oil to the recommended level. Make sure you TURN OVER THE GEARS a couple of times so they get coated in oil. Just spin the input shaft by hand to turn the gears. If you're really keen do it in 1st through to 5th and reverse.

Should be good to store in your garage for several years if you do this and occasionally turn it over.

You should see some of the things I've done to a gearbox and still been able to use it.

Cheers

Paul

[Alex Mckenzie]

I admit it was a dry assembly, I only coated the bearings, she is almost back together, just need to get a few hours to play.
this time everything is coated in oil..
a question on oil.. it recommended to use GL4 but when I look at oil manufacturer sites many advise GL5 is recommended. I read on one forum that the GL5 would eat away at the syncros, id this true or a wives tail ?