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Starlight Silver MG TF 135
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Discussion Starter · #1 ·
I have recently decided that I should drain & replace the gearbox oil on my 2002 MGTF135. Reasons are:
1. Advice on this site & elsewhere advises that it should be changed every 7 years, regardless of mileage.
2. Although I have all receipts for all past service work, there is no mention anywhere of a gearbox oil change.
3. The car is fast approaching it's 20th Birthday (Sept. 13th.), so new gearbox oil seems like a good Birthday Present.

I nearly bought one of the recommended oils from Rimmers, which looked like a "bargain":
Liquid Fluid Cosmetics Font Technology


I decided instead to buy from my local MPD car parts place, which cost more, but I am now glad I did not buy the MG Rover branded stuff, as it is almost certainly "New Old Stock", dating from 2005 or before.

The Comma MVMTF 75W80 stuff I bought, which both Halfords website and my local MPD shop assure me is the right stuff for a TF, has a manufacture date of 14/07/2022, and a notification advising that "Expiry Date 5 years after production date"
Font Commemorative plaque Automotive tire Paper Publication


It seems unlikely that the MG Rover branded oil was either produced recently, or somehow has a shelf-life more than 4 times longer than the Comma stuff (assuming it was manufactured before Rover went into receivership). My conclusion is that I nearly replaced 20 year old, worn-out oil, with (probably) 17 year old "clean" oil which is WAY past it's "Use-By" date.

Am I missing some vital fact here? Are there any oil-industry experts out there who can explain why oil has a shelf-life, or to what extent it degrades in storage?

Also, once I saw the old oil, I was glad I did the oil-change (following advice on this site, and refilling via a tube fed from the engine access in the boot)

The good news is that there was more than 2.2 litres of oil in the gearbox, and there were no signs of metallic debris (nothing collected on a cleaned magnet in the drain receptacle). The bad news is that the oil was badly discoloured:
Serveware Porcelain Drinkware Gas Drink


So if you have any doubts about when your gearbox oil was last changed, it would be worth planning a drain-and-refill, when convenient. Also, be careful to avoid buying ancient oil!

To be fair to Rimmers, the first item offered was Land Rover branded stuff, which presumably is much more recently manufactured than the MG Rover-branded stuff. I would be interested to know if that oil, or other suitable oils display any "Expiry" dates.
 

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'06 MG ZR +120 (HQM) '04 MG ZR 105 (IAB)
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.......but I am now glad I did not buy the MG Rover branded stuff, as it is almost certainly "New Old Stock", dating from 2005 or before.................It seems unlikely that the MG Rover branded oil was either produced recently
Not sure how you come to that conclusion?

XPart are still in existance (now part of Leacy Classics) and still supplying MG Rover spares and fluids, often still packaged in the standard black MG Rover packaging, so it is not at all certain that consumables such as oils would still be left in stock from 17+ years ago and Rimmer Bros are a current XPart reseller and wholesaler to the trade.

Oils are always quoted with an expiry date, but if unopened/sealed I think any deterioration would be minimal if there was any deterioration at all tbh.

The official MG Rover maintenance check sheets give a manual gearbox oil change interval of 7 years or around 105000 miles whichever is sooner (the exact mileage interval varies slightly between the different ranges as it is set to fit in with the normal cycle of service intervals), so I would think giving it a change after 20 years is a very good idea, especially if it hasn't had a change before.

MG Rover used MTF94 as it was a longer service interval version of standard 75W80 gearbox oil. If using ordinary 75W80 which is not designated as MTF94 (and not rated as a direct equivalent of MTF94) the change interval will be less than half the 7 years/105k miles for the MTF94.
 

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Starlight Silver MG TF 135
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Discussion Starter · #3 ·
XPart are still in existance (now part of Leacy Classics) and still supplying MG Rover spares and fluids, often still packaged in the standard black MG Rover packaging, so it is not at all certain that consumables such as oils would still be left in stock from 17+ years ago and Rimmer Bros are a current XPart reseller and wholesaler to the trade.
O.K., I stand corrected, and I now understand what the main difference is between normal 75W80 oil and the MTF84 stuff.

Anyone bothering to read this thread will now know (thanks to your information) why they should choose MTF94, unless they are prepared to change gearbox oil more frequently. I am guessing that the other point which emerges from all this, is that a previously part-used bottle of oil, left on the shelf in someone's garage after topping-up a gearbox or whatever, is likely to be degraded, if they use-up the remaining oil several years later. Presumably, that is why an "Expiry Date" is quoted. It seemed to me unlikely that an unopened bottle of oil could/would degrade much, which is why I asked the question about shelf life in the first place.

Decanting a partially emptied bottle of oil into a transparent container and leaving in sunlight on a garage shelf would presumably increase the degradation? Minimising the air above the oil (kept cool in the original bottle) MIGHT help??

Thanks for the reply and correction, anyway!
 

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MG ZT, Rover 25
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I usually change g/b oil when I do the clutch. Worth checking the oil level occasionally, I had to change the g/b on a 200 as it was damaged through running with only around 1/2 litre of oil in it. No obvious leaks in my ownership, but clearly not checked in services.
 

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The question of expiry dates on oil is interesting. As oil is now packed in plastic containers, it is worth noting that all plastics are permeable to some extent, so both water vapour and carbon dioxide can diffuse in, and perhaps form carbonic acid. Other chemical changes may well be possible. I worked in the Defence industry and the MoD very often imposed shelf lives on many products such as paint (opened or not). Don't know about oil.

Ah, good old MTF94.... I put it in my Rover 600 gearbox (Honda) but it was not good and I had to replace it with Honda MTF3. However, some time later I was trying to find a good gearbox fluid for my Toyota Celica and some people suggested Red Line MT90. I found out that MTF94 has very nearly the same spec as Red Line MTL and so I put the spare 94 I had into the Celica, which was very happy with it! Todays boxes can be quite picky about what they'll accept; it's not just about lubrication, it's about spinning up the shafts.
 

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mg_tf
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I found it was a bit of a head scratcher when replacing my gearbox and what to fill it with. In the end, I went for the MTF94 and bought mine from Smith and Allen who sell a wide variety of oils and OAT Anti freeze with a great technical desk if you fancy a chat to make sure it's fit for purpose.
 
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