Check this out corrosion after 4 days

**Alex Mckenzie** · 06-09-2014, 05:41 PM

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.

Check this out corrosion after 4 days-image-jpg

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** · 07-09-2014, 12:06 AM

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** · 07-09-2014, 01:04 AM

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** · 07-09-2014, 09:13 AM

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** · 07-09-2014, 10:06 AM

Originally Posted by 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

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** · 07-09-2014, 06:37 PM

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** · 07-09-2014, 07:12 PM

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** · 07-09-2014, 07:47 PM

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** · 08-09-2014, 06:11 PM

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.