Possible Automatic box slipping

[monkey]

Hi new to the site thanks for any information and advice.

Hi just bought a 1987 998 mini city and feels like the auto box is slipping if you put your door down the revs pick up and strange noise happens fir second or so .
If you drive in manual it does seen to happen as much but just as you pull off it judders any idea will a simple oil change help or is ot a rebuild? ?? Thanks for the help much appreciated. ..

[monkey]

Mar 10, 2018 18:10:12 GMT monkey said:

Hi new to the site thanks for any information and advice.

Hi just bought a 1987 998 mini city and feels like the auto box is slipping if you put your foot down the revs pick up and strange noise happens for a second or so .
If you drive in manual it does seen to happen as much but just as you pull off it judders any idea will a simple oil change help or is ot a rebuild? ?? Thanks for the help much appreciated. ..

[69hcode]

Always start with an oil change on these. It might just have the wrong oil in it. I run 10w40 MA2 motorcycle oil. That would be best for the clutches. 


Where are you located? Might be someone close that could help out. It might be a good idea to check the kickdown linkage adjustment and the shift cable adjustment. 

[monkey]

Hi will change the oil and try that hopefully that will sort it.
I'm in Lincoln how would I check the linkages ...

[69hcode]

Use the search on here. Many on here have said how to do it in better words than me. 


Do you have a hanes manual. It should say how to do it pretty well. 

[monkey]

Hi I have been to get the oil today and I have got 10w40 but it's MA-2 is this the correct oil thanks for the help again

[monkey]

Mar 11, 2018 21:55:18 GMT monkey said:

Hi I have been to get the oil today and I have got 10w40 but it's MA-2 is this the correct oil thanks for the help again

[notamini]

Can we all assume that you are in Lincoln Nebraska, USA?
You might want to start at austinamericausa.com/
Check out the Technical advice section under AP automatic transmission. Kickdown is in there somewhere.

Mark

[thezp]

I use Valvoline VR1 20W50 due to it's Zinc Content and it being mineral oil....which is what these cars where built to run on.  Like said before, start with the oil change then check the other issues.  Just be careful because the little piece of junk plastic that attached your kickdown to the governor could break like mine did.  I'm actually trying to find a metal replacement since you'll not be able to locate one online anywhere for sale.  I plan on updating once I find what works best.  Good luck on your problem.

[notamini]

Many of us on here thought 20W50 was the best but it is way too heavy and has been known to cause slippage and sluggishness. According to Richard1 on here, who is an expert in the oil industry, the best combo is 10W40 MR2 motorcycle oil for "wet" clutches.

[thezp]

odd seeing that 20w50 is what is recommended on all the classic sites.  plus the VR1 is racing oil.  I'll ask other people what they think about using moto oil.  We have guys here in Texas using full synthetic too.

[notamini]

Maybe you should also PM Richard1 and ask him the differences. Synthetic has always been considered a big no no in automatics. If you could find his posts here he explains all of this. Or, as I said, PM you concerns to him. I just know my America works very nicely on 10W40 MA2.

Mark

[thezp]

Thank you for the insight.    

[richard1]

Tarija and Santa Cruz, Bolivia

You absolutely do not want VR1.
First requirement is that it be MA2 motorcycle oil. It has the additives to make the clutches stop slipping.

Second requirement is to have a viscosity that can dissipate or flow off the disc faces so they can grab. 20W-50 flows much more slowly and will therefore cause slipping to some extent until it heats up and drains off. So I recommend 10W-40. If your engine is in such poor shape as to need more viscosity to not burn it, you get to decide whether to use 20W-50 and cause more damage to it and the transmission, add oil more frequently, or rebuild it. I recommend a rebuild, as at that point you can probably replace rings and bearings, not having to over-bore. A repair in time saves the dime. Rings and bearings are cheap. Pistons and reboring are expensive.

As for synthetic vs mineral, it doesn't matter if they meet the same standards. A 10W-40 MA2 mineral oil and a 10W-40 MA2 synthetic oil pass the same tests for clutch grabbing (some brands better than others). The synthetic will be better for longer drain intervals, sludge avoidance, and hot temperatures. But try as I might, I can't get my Mini too hot. I use 10W-40 mineral MA2.

[jockduck]

I thought that the problem with some oils was the use of friction modifiers which cause slippage in wet clutches, obviously MA2 oils do not have friction modifiers, Oil manufacturers are a bit coy about whether they use F/Ms or not, very light fuel saving engine oils usually have friction modifiers 0w-30 for example. I have always used 20-50 mineral oil because I lived in the tropics but now I have moved to a cooler climate I'm going for a 10-40 next oil change to improve the gearbox performance in cold weather.
Jock

[richard1]

Tarija and Santa Cruz, Bolivia

Gasoline engine oils have friction modifiers to make them more slippery. Diesel oils do not, so do not slip as much. Motorcycle oils have friction modifiers in the other direction, to make them grab when certain conditions are right. To be more exact:

A modern gasoline engine oil has a dynamic friction coefficient of 0.01
Teflon on Teflon has a dynamic friction coefficient of 0.04 (another reason teflon additives are a joke)
Diesel oils has a dynamic friction coefficient of 0.80 to 1.00
Motorcycle MA1 has to fit a range between 1.30 and 1.85 on the two most critical tests
Motorcycle MA2 oils have to fit into a range of 1.88 and 2.50 on those two tests.