Bobdog

Bobdog

Well-Known Member
Thought a while back that my auto gearbox didn't seem quite right. Just didn't feel quite like it was changing up like it should but barely noticeable. Anyway, I thought I should probably do an oil change in the near future but finding the time in my hectic life is always difficult.
Earlier today however, it started shuddering slightly at around 3rd gear. Then tonight it's shuddering slightly worse and struggles to change up to 3rd, revs flaring a bit before eventually changing up.
Urgent oil change required I think... I hope....
 
Often a Shift flare is the first sign of low fluid pressure or worn clutches etc etc ...

Check the fluid level and colour, black transmission fluid signifys worn clutches,

Similarly low fluid will cause transmission slip as the fluid pressure is below the required Pressure and will not allow proper clutch engagement.

with the disco idling and upto temp.

Run it through the gears pausing in each for 3 seconds.

Then crawl inderneath and pull the filler plug out, a steady steam of fluid SHOULD trickle out, if not the fluid is low, top up or replace.

If you drop the sump take note of the fluid colour and pan condition, most of the time a worn Box will leave a sludge in the pan which is clutch material..

Also smell the fluid old worn "burnt" fluid will smell foul, compared to the sweet ATF smell.

Also worth noting Valvebody solenoids worn or full of crap

And a Blocked Oil filter.

Both causes of the above.
 
If the oil was ruled out you can rule out other things by making a stall test
Stall test.jpg
 
Henry_b said:
Often a Shift flare is the first sign of low fluid pressure or worn clutches etc etc ...

Check the fluid level and colour, black transmission fluid signifys worn clutches,

Similarly low fluid will cause transmission slip as the fluid pressure is below the required Pressure and will not allow proper clutch engagement.

with the disco idling and upto temp.

Run it through the gears pausing in each for 3 seconds.

Then crawl inderneath and pull the filler plug out, a steady steam of fluid SHOULD trickle out, if not the fluid is low, top up or replace.

If you drop the sump take note of the fluid colour and pan condition, most of the time a worn Box will leave a sludge in the pan which is clutch material..

Also smell the fluid old worn "burnt" fluid will smell foul, compared to the sweet ATF smell.

Also worth noting Valvebody solenoids worn or full of crap

And a Blocked Oil filter.

Both causes of the above.
Click to expand...
I'm doing an oil change today, does it need to be cold to do it or up to working temperature?
 
Henry_b said:
Often a Shift flare is the first sign of low fluid pressure or worn clutches etc etc ...

Check the fluid level and colour, black transmission fluid signifys worn clutches,

Similarly low fluid will cause transmission slip as the fluid pressure is below the required Pressure and will not allow proper clutch engagement.

with the disco idling and upto temp.

Run it through the gears pausing in each for 3 seconds.

Then crawl inderneath and pull the filler plug out, a steady steam of fluid SHOULD trickle out, if not the fluid is low, top up or replace.

If you drop the sump take note of the fluid colour and pan condition, most of the time a worn Box will leave a sludge in the pan which is clutch material..

Also smell the fluid old worn "burnt" fluid will smell foul, compared to the sweet ATF smell.

Also worth noting Valvebody solenoids worn or full of crap

And a Blocked Oil filter.

Both causes of the above.
Click to expand...
Ok, here's the drained oil-
20190625_142316.jpg


You can see the colour on the side of the bowl. It doesn't smell too bad, sort of 'nutty' lol.
Now off to get a garden sprayer to refill, as I realised I left mine in the mother in laws shed... :rolleyes:
 
Bobdog said:
Ok, here's the drained oil-
View attachment 182257

You can see the colour on the side of the bowl. It doesn't smell too bad, sort of 'nutty' lol.
Now off to get a garden sprayer to refill, as I realised I left mine in the mother in laws shed... :rolleyes:
Click to expand...
Hmm defo dirty.

Fill when cold till it drips out of the filler hole, start the motor run it through the gears pausing in each for 3 seconds..

Then top up til it comes out, again cyle through the gears recheck add if necessary.

And you're done!!
 
Henry_b said:
Hmm defo dirty.

Fill when cold till it drips out of the filler hole, start the motor run it through the gears pausing in each for 3 seconds..

Then top up til it comes out, again cyle through the gears recheck add if necessary.

And you're done!!
Click to expand...
Well.... all done. However... I may have completely mis-diagnosed the problem. Took it for a test drive and the judder I thought was clutch slip is still there. I think the "flare" I had, was actually the gearbox kicking down to try to compensate for lack of power. It won't rev over 2500rpm unless I floor it, (which I'm guessing it would if it was clutch slip) then it gets up to about 3000rpm. I'm now thinking the "judder" may actually be a misfire.
Great.... :(
 
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