topping up the gearbox with reduction boxes?

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BIG_TEXAS_PETE
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topping up the gearbox with reduction boxes?

Post by BIG_TEXAS_PETE » Tue Aug 13, 2019 2:23 pm

i'm a bit unsure how i should top it up?

If i jack up the van the wheels hang down, therefor i assume over filling the reduction boxes? Is this right?

How do i just top it up? I cant find the answer in the manual.

Thanks

Peter


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Re: topping up the gearbox with reduction boxes?

Post by BIG_TEXAS_PETE » Tue Aug 13, 2019 2:31 pm

Do i top it up with the wheels on?


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Re: topping up the gearbox with reduction boxes?

Post by BIG_TEXAS_PETE » Tue Aug 13, 2019 3:27 pm

I just spoke to my friendly local VW specialist.

They've told me wheels on, all on the flat. You should just be able to feel the oil with your finger. Make sense really.

Cheers

Peter

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Re: topping up the gearbox with reduction boxes?

Post by 8 8US » Tue Aug 13, 2019 8:18 pm

If you’re completely replacing the oil, it’s 0.25l in each reduction box, then fill the gearbox until it starts to come out of the filling hole.

If you’re topping up just top up the gearbox until it starts to come out the filling hole, assuming your stock height, if not jack up the rear until stock height leave it a while for the gearbox oil to flow back to the box and check.

Don’t forget if you plan on draining rgbs and/or gearbox check the filling caps come undone before you undo the drain plugs, otherwise you’ll have no way of filling!
Richard

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Re: topping up the gearbox with reduction boxes?

Post by TEXAS_PETE » Wed Aug 14, 2019 11:37 am

Thanks Richard.

Yes i'm at stock height.

I'm planning on running the bus for a month or so then dropping the lot and renewing it all. I just didn't want to do that and maybe find a leak.

Cheers mate.

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Re: topping up the gearbox with reduction boxes?

Post by maddison » Wed Aug 14, 2019 1:10 pm

BIG_TEXAS_PETE wrote:
Tue Aug 13, 2019 2:23 pm


If i jack up the van the wheels hang down, therefor i assume over filling the reduction boxes? Is this right?

the oil in the RGBs doesnt have anything to do the oil in the gearbox, x3 seperate cases


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Re: topping up the gearbox with reduction boxes?

Post by TEXAS_PETE » Wed Aug 14, 2019 2:02 pm

maddison wrote:
Wed Aug 14, 2019 1:10 pm


the oil in the RGBs doesnt have anything to do the oil in the gearbox, x3 seperate cases
What makes you say that? It says it does in everything I've read, post's on the samba and a specialist all say it does?


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Re: topping up the gearbox with reduction boxes?

Post by TEXAS_PETE » Wed Aug 14, 2019 2:11 pm

Just for clarity on what i personally did.

I renewed the oil bearing seal on one side, filled that reduction box with 0.25l as per the manual. Then put the wheels back on got her flat and level and topped up the gearbox. As everything I've read said they're connected.


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Re: topping up the gearbox with reduction boxes?

Post by TEXAS_PETE » Thu Aug 15, 2019 9:37 am

This section in the workshop manual actually answers my initial question... But i couldn't find it at the time.

I cant find any %100 information telling me that they are connected. But lots of posts on the Samba say they are and the ''Important'' box would suggest they are.
oil.jpg

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Re: topping up the gearbox with reduction boxes?

Post by Who.Me? » Thu Aug 15, 2019 12:57 pm

TEXAS_PETE wrote:
Thu Aug 15, 2019 9:37 am

I cant find any %100 information telling me that they are connected. But lots of posts on the Samba say they are and the ''Important'' box would suggest they are.
Yes, they are connected. The outer tube is hollow and open at either end to the gearbox and the reduction boxes. The axles are inside the tube.

I've had to change mine a few times (it leaked when I got it, I had the transaxle rebuilt a couple of years ago, and most recently I used a cheap seal kit and the o-rings shredded). I've only ever done them in pairs though, so have drained the whole thing down each time (gearbox/diff and RGBs).

How did you get on changing the seal with oil still in the gearbox etc.? Did you jack up the reduction box on the side you were working with and did you have much of an issue with residual oil draining out of the reduction box while you were working on the one side?

I always use a sealant (Permatex high-tack) on the gaskets to improve the chance of getting a good seal between the RGB case and brake back plate and between the back plate and bearing carrier. Oil would mess with the sealant.

I need to do my offside one again as it's started weeping. Nearside is OK this time though, so it would be a bonus if I could avoid draining the whole thing down (refilling is messy, smelly and takes ages).

For what it's worth, if you ever have to do it again, don't be tempted to get ahead of yourself and fill the box before you've got the drum on and hub nut torqued. It's easier to refill the RGB with the road wheel out of the way, but make sure that the hub nut is fully torqued before you fill up. If not, you'll likely get leakage past the o-ring as it won't be properly compressed. You'll sometimes get leakage if you're changing the rear shoes for the same reason. That doesn't (always) mean that the seal has failed though, it may just be because the pressure is off that o-ring.


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Re: topping up the gearbox with reduction boxes?

Post by TEXAS_PETE » Thu Aug 15, 2019 2:54 pm

Hi WM

Well funny you say ''you sometimes get leakage if you're changing the rear shoes'' That's exactly what happened! I was only originally changing all the brakes and it dropped out all its oil and at sometime in its life someone had put the bearing seal cover on upside down. So i seen this as an opportunity to fix that.

I didn't know how much oil was going to come out of the reduction box drain plug at the time, I just caught it in a plastic oil drain bowl. I couldn't say how much. but looking back now more than .25 liters. i let it run dry and left the plug out until the job was done. I agree the stuff stinks!

After obsessively cleaning for about an hour.. I fitted a new outer seal (in the bearing cover) and gasket with some RTV on both sides.

Just out of interest are you on 46mm rear nuts?

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Re: topping up the gearbox with reduction boxes?

Post by Who.Me? » Thu Aug 15, 2019 6:07 pm

TEXAS_PETE wrote:
Thu Aug 15, 2019 2:54 pm


Just out of interest are you on 46mm rear nuts?
Thanks for the info. Yes, my truck has the big nut transmission.

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Re: topping up the gearbox with reduction boxes?

Post by vwJim » Fri Aug 16, 2019 8:13 am

TEXAS_PETE wrote:
Wed Aug 14, 2019 2:11 pm
Just for clarity on what i personally did.

I renewed the oil bearing seal on one side, filled that reduction box with 0.25l as per the manual. Then put the wheels back on got her flat and level and topped up the gearbox. As everything I've read said they're connected.
Perfect.

They're definitely connected and oil flows / mixes between all the casings.
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.


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Re: topping up the gearbox with reduction boxes?

Post by TEXAS_PETE » Fri Aug 16, 2019 8:47 am

Thanks both of you.

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