Pure guesswork filling up a gear box?

Pure guesswork filling up a gear box?

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Bobton125

Original Poster:

253 posts

68 months

Thursday 23rd January 2020
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Unsure how to upload pictures so i'll try to describe it..

I have a PGO 250 road legal buggy with a 250cc automatic quad bike engine with no real info in manuals or owners clubs.

Looking directly from the back you can see the auto gearbox on the left, driving the final drive box in the middle via an input shaft (which enters the final drive quite high up the casing)

The final drive gear box is a very tall and thin rectangle shape. It has a drain hole on the bottom, a fill hole on the top and what i think is the oil level blow hole on the side. However this random hole is very high up the casing, if i were to fill until gearbox oil would run out, it would probably be about 80% full.
The hole is roughly the same level as the input shaft

My question is, how much would you fill a final drive gearbox if you have no manuals to hand? Should it be up until this random hole on the side of the casing which just so happens to be level with the input shaft? There is a breather pipe at the top too so am i right in thinking if overfilled, oil will just come out rather than being too high pressure?
Thanks!







Edited by Bobton125 on Thursday 23 January 13:12


Edited by Bobton125 on Thursday 23 January 22:31

E-bmw

9,105 posts

151 months

Thursday 23rd January 2020
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A quick google finds this, don't know if it is yours or not.

From this distance I can't be sure but it looks like the final drive from the gearbox is an enclosed chain & the "gearbox" to which you refer is the differential assuming it is the bit the drive shafts come out of.

This should have a fairly high level I would have thought as there will be gears at the top of it to convert the drive.

Can't see properly but from that pic, that would be my best guess.

Krikkit

26,500 posts

180 months

Thursday 23rd January 2020
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E-bmw said:
From this distance I can't be sure but it looks like the final drive from the gearbox is an enclosed chain & the "gearbox" to which you refer is the differential assuming it is the bit the drive shafts come out of.

This should have a fairly high level I would have thought as there will be gears at the top of it to convert the drive.

Can't see properly but from that pic, that would be my best guess.
Assuming the pictures match this is solid advice - that final drive unit won't take much harm from a decent level of oil, like a differential.

I assume it's a 250cc moped engine and gearbox, then the final drive unit tied onto the output shaft, which then integrates the reverse mechanism, diff, and the shaft outputs.

Olas

911 posts

56 months

Thursday 23rd January 2020
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My gut says drain into a graduated container and refill the same volume you removed, although this assumes the level is correct.

It would be helpful if you could see a part number on the component. Old wisdom says to use the bottom of the fill hole as the level, so you fill until it just starts to seep from the fill hole.
The hole high up the side of the casing is more likely a vent than a level, fluid expands/contracts with heat and the air has to go somewhere.

Bobton125

Original Poster:

253 posts

68 months

Thursday 23rd January 2020
quotequote all
E-bmw said:




A quick google finds this, don't know if it is yours or not.

From this distance I can't be sure but it looks like the final drive from the gearbox is an enclosed chain & the "gearbox" to which you refer is the differential assuming it is the bit the drive shafts come out of.

This should have a fairly high level I would have thought as there will be gears at the top of it to convert the drive.

Can't see properly but from that pic, that would be my best guess.
That is the exact model. The gearbox has a drivebelt rather than a chain but you are correct

Bobton125

Original Poster:

253 posts

68 months

Thursday 23rd January 2020
quotequote all
Olas said:
My gut says drain into a graduated container and refill the same volume you removed, although this assumes the level is correct.

It would be helpful if you could see a part number on the component. Old wisdom says to use the bottom of the fill hole as the level, so you fill until it just starts to seep from the fill hole.
The hole high up the side of the casing is more likely a vent than a level, fluid expands/contracts with heat and the air has to go somewhere.
I drained 2 litres out of it, i've filled it back up with 2 litres but it still hasn't reached the suspected oil level hole on the side yet. Saying that though, how would i know if the last person who changed it used the correct amount..
I'll try to figure out how to upload pictures later on.

the fill hole is right at the top face of the box i the box would be 100% full of oil if i filled up to that. The suspected oil level hole high up the side is blocked with a bolt so is definitely not a vent.



Edited by Bobton125 on Thursday 23 January 15:10

Olas

911 posts

56 months

Thursday 23rd January 2020
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Fit a temperature sensor to guesstimate how hot (and by association how stressed) the oil is and adjust the level until you see a temperature you approve of?

GreenV8S

30,150 posts

283 months

Thursday 23rd January 2020
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Olas said:
Fit a temperature sensor to guesstimate how hot (and by association how stressed) the oil is and adjust the level until you see a temperature you approve of?
Being overfilled is likely to cause additional heating due to stirring - I wonder whether the symptoms of underfilling might be noise and wear rather than heat.

Auntieroll

543 posts

183 months

Thursday 23rd January 2020
quotequote all
FFS the free downloadable manual tells you the capacities for refilling !!
The drain hole is the one at the bottom ,the vent hole is the one removed to drain the oil ,the filler is on the top .
Instructions are quite specific , if you read them.
Sorry to sound like DCW but......

Bobton125

Original Poster:

253 posts

68 months

Thursday 23rd January 2020
quotequote all
Olas said:
Fit a temperature sensor to guesstimate how hot (and by association how stressed) the oil is and adjust the level until you see a temperature you approve of?
that's far too complicated

Bobton125

Original Poster:

253 posts

68 months

Thursday 23rd January 2020
quotequote all
Auntieroll said:
FFS the free downloadable manual tells you the capacities for refilling !!
The drain hole is the one at the bottom ,the vent hole is the one removed to drain the oil ,the filler is on the top .
Instructions are quite specific , if you read them.
Sorry to sound like DCW but......
I've searched all over the internet. I can find the 180ml capacity for the cvt gearbox but nothing for the final drive. Please link it up if i've missed something but i've been looking at all the manuals for quite some time now!

Bobton125

Original Poster:

253 posts

68 months

Saturday 25th January 2020
quotequote all
Pictures now added in original post