back axle oil change

Helsbyman · Post by **Helsbyman** » Sun Mar 27, 2011 6:16 pm

Hi there, can any one tell me when you are supposed to change your back axle oil on a TF 160

Stan_B · Post by **Stan_B** » Sun Mar 27, 2011 7:30 pm

The reason you change engine oil is because combustion by products get past the rings etc and pollute it turning it acid corroding the engine and also the viscoscity additives degrade with time. The oil is unaffected and if you take it to a re-cycling point you may buy it back later after its cleaned and has the additives replaced. Engine oil out of the can is often a bit basic so it goes basic neutral then acid during its service life. So gearbox and axle oil has an indefinite life. I do replace mine in the B once in a while (years) and it does come out quite black probably a mix of dirt and mechanical debris and I had all oil changed when I got the TF during the cambelt service. I expect it was the original in there.

Helsbyman · Post by **Helsbyman** » Sun Mar 27, 2011 8:08 pm

Hi Stan b, you say gear box oil has a long life but if i remember well, it says it should get changed at 50k and this is why i asked about the axle oil, as my axle oil has done 55k/6yrs and there for wondered if there was a sevice time/milage at which it shoud get changed
Thanks for your input

MartinW · Post by **MartinW** » Mon Mar 28, 2011 6:29 am

As far as I know, but I stand to be corrected, technically there is not a back axle. The diff shares its oil with the gearbox in the same way the FWD cars do. Therefore to change the oil, you need to remove the plug on the gearbox and then drain it (preferably as soon as possible after a long drive that will have got the oil as warm as possible in the gearbox). To refill, refit the drain plug, and then remove the small plastic breather cap and pour fresh oil in via the breather, and be careful to put the exact amount in as there is no easy way to check the level. This is how I did it on my wife's 1998 Rover 214 a few years ago, which is not dissimilar to the MGF/TF, I would have thought although I know there was a change to the type of gearbox used which were reputed to be sealed for life.

Engine oils suffer from the high levels of heat which will shorten its life. Added to which some fuel dilution (not as much as the days of carburettors) and other contaminants such as soot particulate (worse on diesels) will determine the need for a more frequent oil change. Apart from the quality and base oil type then depending on whether used for short trips or long trips and also the time of year (temperature) the oil may be fit for 12k miles or it may not manage 3k miles in the worst case.

Because of the improvements in sulfur reduction in the fuel, the need for overbased detergents has also been reduced since that risk of corrosion has also been reduced, along with better engine management systems. Compared to 20 years ago, the base reserve of petrol engine oils is quite a bit lower. The use of synthetic base stocks has alo increased the performance of the oil. Semi-synthetics are not controlled or regulated so a semi-synthetic typically will only have a maximum of 30% by volume of synthetic base oil, the rest being mineral, so a better term would be part-synthetic in my view. Mineral oils and some semi-synthetic oils still need Viscosity Index Improver additives which are susceptible to breakdown resulting in your 10W40 acting like a 10W30 oil. Typically though, this breakdown will take place very quickly and then stabilise, but this is why B owners find their oil pressure increases after a service as the 20W50 they would typically use would reduce over the service life of the oil to 20W40 or lower depending on quality.

As to gear oils, the thinking was that mechanics did more damage putting 'dirty' new oil into a gearbox than to just leave the oil alone to begin with, the dirt being caused by use of dirty containers and cross-contamination from other oils. The dirt we're talking about is invisble to the human eye, the most damaging particle size being less than 10µm. That said a gearbox still generates some heat, as well as aeration, and of course has some reactive wear metals, along with the possibility of some condensation after use when cooling down. Heat, reactive metals, water and oxygen are the 4 catalysts of oxidation so a gear oil (or diff oil) are very likely to suffer all of the above over a 5-10 year period resulting initially in the darkening of the oil and ultimately in sludge and oil thickening. I would agree that changing every 5 years is good practice, and make sure it is the recommended type and if it does not need an EP (Extreme Pressure) oil then don't use one as the sulphur phosphorous EP additive can attack yellow metals at higher temperatures and also cause problems with the synchro-mesh rings not working correctly.

For more reading - http://www.oils4mgs.co.uk

Ralph · Post by **Ralph** » Mon Mar 28, 2011 10:37 am

When the F was launched MGR stated that the gearbox was filled for life, i.e. you never had to change the gearbox oil. Later they modified this to changing the oil at the 105k service.

GeoffW · Post by **GeoffW** » Fri Apr 22, 2011 10:41 pm

I changed the oil in my zt 260 and it made a difference to the gear change

Rich in Vancouver · Post by **Rich in Vancouver** » Sat Apr 23, 2011 3:52 pm

Just one other thought on this.
MG Rover never intended these cars to be driven for fifteen plus years (no follow up sales that way!) so extended age
of the lubricant would not have been a consideration for them.
When I bought my 15yo MGF I changed the gearbox oil just to be on the safe side.

talkingcars · Post by **talkingcars** » Sat Apr 23, 2011 10:23 pm

MartinW wrote:.................To refill, refit the drain plug, and then remove the small plastic breather cap and pour fresh oil in via the breather, and be careful to put the exact amount in as there is no easy way to check the level...............

The correct level is when it starts to come out of the filler hole.

GeoffW wrote:I changed the oil in my zt 260 and it made a difference to the gear change

The ZT260 is front engine rear drive so the gear box is different to the bulk of MGs where the engine is at the same end as the gearbox and drive.

The PG1 gearbox as found on some MGFs uses a special gearbox oil as opposed to most gearboxes that can use engine oil.

redarrow · Post by **redarrow** » Sat Apr 23, 2011 10:36 pm

The gearbox oil you need is called, ((MTF 94)), nothing else is correct.

The gearbox is 2.3 ltrs full.((pg1 gearbox))

might as well get 5 liters £28, or £9 roughly a liter.

A video link below , to help others no how to do, a gearbox oil change.

http://www.youtube.com/watch?v=isWCtbEcTNE

redarrow · Post by **redarrow** » Sat Apr 23, 2011 11:21 pm

When you drain the gearbox on a pg1, what the size of the washer, needed to be replaced????

anybody?

below, is the proper makings of the pg1 gearbox, there no size of the washer to be replaced after filling with new oil.?????????

i think it called, 82 on list below,filler level plug, ((no washer/seal size)

MANUAL GEARBOX
GEARBOX
COMPONENTS
- PGl GEARBOX
1. Oil seal - differential
2. Differential housing
3. Speed sensor - instruments
4. Dowel
5. Oil seal - selector rod
6. Boot
7. Selector rod
8. Thrust washer - sun gear
9. Sun gear
10. Thrust washer - planet pinion
11. Planet pinion
12. Pinion shaft
13. Ball bearing - differential
14. Final drive gear
15. Roll pin - differential pinion shaft
16. Differential casing
17. Ball bearing - differential
18. Selective shim
19. Clutch release arm
20. Oil seal - clutch release arm
21. Selector rod guide
22. Dowel bolt and washer.
23. Magnet
24. Detent cap bolt, ball and spring - selector rod
25. oil guide plate
26. Parallel roller bearing - countershaft
27. Countershaft
26. Selective thrust washer - 1 st gear end float
29. Needle roller bearing - 1st gear
30. 1st gear
31. Synchro ring - 1 st gear
32. Synchro spring
33. Synchro hub - lW2nd gear
34. Synchro sleeve - lW2nd gear
35. Synchro spring
36. Synchro ring - 2nd gear
37. Selective collar - 2nd gear end float
36. Needle roller bearing - 2nd gear
39. 2nd gear
40. 3rd gear
41. 4th gear
42. 5th gear
43. Roller bearing - countershaft
44. Ball bearing - countershaft
45. Washer
46. Countershaft nut - L.H. thread
47. Circlip
48. Reverse idler shaft
49. Thrust washer - reverse idler gear
50. Roll pin - reverse idler shaft
51. R8v8t'Se idler Q8a
52. Reverse fork
53. Oil seal - mainshaft
54. Ball bearing - mainshaft
55. Mainshaft
56. Needle roller bearing - 3rd gear
57. 3rd gear
56. Synchro ring - 3rd gear
59. Synchro spring
60. Synchro hub - 3rd/4th gears
61. Synchro sleeve - 3rd/4th gears
62. Synchro spring
63. Synchro ring - 4th gear
64. 4th gear
65. Needle roller bearing - 4th gear
66. Distance collar - 4thEth gears
67. Needle bearing - 5th gear
68. 5th gear
69. Synchro ring
70. Synchro spring
71. Synchro hub - 5th gear
72. Synchro sleeve - 5th gear
73. Ball b8ariftg - mainshaft
74. Selective snap rings - mainshaft end thrust
75. Belville washer - mainshaft end thrust
76. Oil guide plate
77. Gearbox casing
78. Reverse idler shaft bolt and washer
79. Breather pipe
80. Breather pipe bracket
81. Oil seal - differential
82. Filler/level plug
83. Drain plug
84. Access plug - countershaft bearing circlip
65. Reverse light switch
66. Shift arm assembly
87. Interlock
66. Shift arm guide
89. Shift shaft
90. Roll pin - Sth/reverse gear selector
91. Gear selector - Sth/reverse gears
92 Selector fork - 3rd/4th gears
93. Selector fork - 5th gear
94. Selector shaft - Sth/reverse gears
95. Selector fork - lW2nd gears
96. Selector shaft - lsV2nd gears

talkingcars · Post by **talkingcars** » Sun Apr 24, 2011 8:51 am

82 is the plug for the filling hole on the side of the box, 83 is the drain plug.

Post by **Mykel** » Sun Apr 24, 2011 9:51 am

Washer is 14mm, part No 19 here.

redarrow · Post by **redarrow** » Sun Apr 24, 2011 1:00 pm

cheers m8 happy easter.

MGsteveT · Post by **MGsteveT** » Sun Apr 24, 2011 1:51 pm

MTF94 is actually a 10W/40 Grade Oil but has an extended work life.
The PG1 Gearbox was originally designed to take 10w/40 Grade Oil and changed every 48000miles but in 1994-ish it was changed to MTF94 to increase it's service life and make fleet servicing etc cheaper. You can use a decent 10W/40 Oil in an MGF Gearbox with no adverse problems but it will have to be changed more regularly. saying that, we've changed the MTF oil at around 40,000miles and the gear selection is made much smoother afterwards.

adrianclifford · Post by **adrianclifford** » Sun Apr 24, 2011 2:54 pm

Great stuff Steve, you can do mine next month then

Post by **Mykel** » Sun Apr 24, 2011 4:29 pm

Hi Steve,

my lil princess has only done 38000 miles but is 11 years old. Would you recommend changing the gearbox oil now?

Thanks and happy Easter,
Mykel

MGsteveT · Post by **MGsteveT** » Sun Apr 24, 2011 5:27 pm

Mykel wrote:Hi Steve,

my lil princess has only done 38000 miles but is 11 years old. Would you recommend changing the gearbox oil now?

Thanks and happy Easter,
Mykel

In my opinion, yes.

You can never 'over-do' Oil changes whether it be the Engine or Gearbox and 6 years is the max i'd personally go to without changing the Gearbox Oil even though you're only doing low miles.

Happy Easter!

GeoffW · Post by **GeoffW** » Tue Apr 26, 2011 9:50 pm

One wonders that from new could there be any small particles of swarf, ect although very small floating about, then theres all those missed changes over the years, plus if only used on short trips could condensation have an effect ??? who knows, just peace of mind with nice new oil inside

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