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GT6 MK1 - Diff Oil Change no drain plug found


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I attempted an Diff Oil change today to find out that I dont have a Sump Plug, this is confusing since my Vin/Engine/Frame No is < 5000. The Haynes manual  reports the manufacturer on later models had decided that oil life will last the serviceable lifetime of the unit;  and only needs the level to be checked at service intervals. Not pleased !&%$** that I dont have a sump plug, so how do I get all the oil out.

I tried to vacuum pump it out with a borrowed Sealey pump (see picture) but only managed to get 300ml. I poked the thinist nylon tube through the level filler plug; but i could not get a bend radius to reach Hypoid casing lower reservoir.

I managed to pump 320ml back in before it started to gush back out. The Diff capacity is 0.57 litre so if regularly do this I will eventually have more new oil than old.

Question:

Is there a better vaccum pump to buy that has an attachment to get in through the filler and down into the Hypoid sump of the diff without hitting the crown wheel/gears.

Has anyone in the same situation considered replacing the Hypiod rear casing for one with a sump plug or is that crazy in time / effort and money.

Glad I stuggled under the car today, I noticed that front mounting plate that supports the diff has oil on it (perhaps the oil seal is weeping) this of course could be a slight positivie; with old oil out and  fresh in. I found oil on the exhaust is this a combustion danger?

Thank you

John

 

 

IMG_1313.JPG

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I only ever did this once on RPK67F (Mk1 GT6) - about 43 years ago - and I used a large syringe which came from the vet's where my sister worked and a length of thin windscreen washer tube. It took a good few pulls on the syringe followed by emptying it before I reckoned I had got most of the old oil out. I didn't measure it but reckon there was more than half a pint. The same syringe was then used to refill the diff. I did have the advantage of having the drive shafts disconnected at the time as I was replacing the UJs.

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Hmm...

I tried and failed to get the oil out of  my Vit diff, after taking it for a run and using a large metal bodied syringe, designed to fill radar gearboxes. I tried several times to get a thin flexible tube down to the front end. It kept fouling the crown wheel.

I'm going to drill the casing and fit a drain plug, like lots of people on here have done successfully.

Gav

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2 hours ago, Top Banana said:

I found oil on the exhaust is this a combustion danger?

no more a smoking problem  hot oil gets a bit fumey

many drill and tap a drain  (in situ) use a greased drill and tap to catch the swarf 

use whatever size you fancy , but a set screw and fibre washer works even a small 5/16"unf  will drain ...nice and slowly 

Pete

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2 hours ago, Top Banana said:

I attempted an Diff Oil change today to find out that I dont have a Sump Plug, this is confusing since my Vin/Engine/Frame No is < 5000. The Haynes manual  reports

Never trust Haynes.

Triumph did, indeed, initially fit drain plugs then deleted them having decided the oil would last the lifetime of the vehicle. However, this was on 948 Heralds. The GT6 never had them.

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not used it much but to swap the oil from 90 to 140 in the 2000 i used a cheap Lidl 12v electric pump has a nice wiggley tube thats drops down ok 

the 140 made it struggle a bit pumping some back  i reverted to the squeeze bottle 

and the diffs much quieter ,at speed now  most noise came from the quillshaft bearing which seemed fine but a new RHP solved some funny diff noises 

on overrun 

Pete

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It's an attractive idea to fit a drain plug in situ!    I've never done it - has anyone here?

Could be messy, but the flow of old oil should wash out any swarf from the hole, and after tapping it, another flush, straight into a bowl, could do the same and be less so.

Any experience?

John

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fit a card disc on the drill bit to spin of the draining fuel or it will run up the drill and ruin your best shirt

if you can drill the crownwheel theres something very  wrong with its heat treatment 

if you drill 8.3mm and tap 3/8 "x24 unf  you get a reasonable drain hole and a simple  3/8unf setscrew and fibre washer will seal it up 

pete

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From no experience at all, I say the opposite to johny and to Pete.

Drill the pilot just too short to break through, then drill the larger size, so that the greater amount of swarf from the bigger hole is washed away more effectively.

Then, I was going to say, use a conical thread sump plug, which will provide a reliable seal without any need for a fibre washer.   But to my surprise, none of the Usual Suspects, Rimmers or Canley, stock them!

Anyone who has been playing this game for as long as I have will have a boxful of conicals.  This sort of thing:

image.png.488d9b4752610bf177fa6f20dd7609c1.png I know - it's filthy.

They are available new in metric sizes, but seem to be out of fashion these days when am interference fit tightness will trump any fibre washer! 

 

As for working on the car in your best shirt .....!!!!!

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My 12V Aldi, Fuel transfer pump with a Small dia suction pipe worked quite well, But I had no body tubs on the chassis at the time.

As For "best" shirts, I still have the Frilly one, Goes with the D-J, for "gentlemens smoking nights", or Institute Dinners. All sadly sat in the wardrobe for many years now!.  The rest would be Jeans, and T shirts/Various. Formal Dinner Dances, could be very expensive, SWMBO never wore the same Dress Twice!!. And "frocks" are not cheap!.😭

Pete

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II drilled this one (Spitfire 1500) in situ, no problems, instead of Pete's idea with the card I used an aerosol cap, drilled the same size as the drill and on the drill to catch any oil and keeping the drill speed low, it all went well. This diff and it's replacement both had a dimple in the casting as a convenient marker point for drilling. Cast iron is lovely stuff to drill, just take it nice and easy. Also, I went for 5/16" UNF and believe me it's plenty big enough, very effective as a drain, even with cold oil. When I'd finished drilling I put some of the old oil back through the diff to ensure there was no swarf inside. Well worth doing.

P.s. It's a short 5/16" UNF set screw with a washer and a sealing washer but also, as it went in to a dry hole, with a smear of loctite on for good measure. The one shown and it's replacement have never leaked.

20220803_072506.jpg

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54 minutes ago, daverclasper said:

What's that stand for Pete?

It's a bearing, one of the better brands.

I was cleaning a spare diff for a Club mate earlier this evening, started to clear off years of grease and turned it over to find:

80848DB0-5238-44BD-BB85-5FD27904B22C_1_105_c.jpg.825e36c27e088e9d17c2154b35408e18.jpg 245E2524-8DA7-407D-ABF2-BA03FDA294AA_1_105_c.jpg.ca560976a2fe0c18a5176dbe7a76b182.jpg

He's NOT getting that one. It's from a 948 saloon so that's the factory drilling from the early days of production.

 

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