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The mkiv Supra Owners Club

Automatic Transmission Questions


Big Mark

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After I bought my auto BPU'd RZ-S I found that it refused to change up at full throttle, this turned out to due to a faulty speed converter but planted the seed of doubt in my head as I have very little knowledge or experience of automatic transmissions. Are the following normal?

 

1. When engaging a gear after start up it usually engages with a jolt, sometimes just a little one, sometimes more severe?

 

2. When stationary (at traffic lights for example) and in D there is a vibration at just the right frequency to make the glovebox lid rattle, but If I go to P then all is fine.

 

3. It feels a little slow getting off the line but again I'm used to manual cars so have nothing to compare it to. Is this just the torque converter doing its thing?

 

Does the above sound normal? I am planning on changing the fluid, I've read that. Removing the sump plug will allow to remove just 2 litres, but to do a full fluid flush is a lot more involved and probably best left to an expert. Would the 2 litre change make a noticeable difference? How much does a full flush cost?

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After I bought my auto BPU'd RZ-S I found that it refused to change up at full throttle, this turned out to due to a faulty speed converter but planted the seed of doubt in my head as I have very little knowledge or experience of automatic transmissions. Are the following normal?

 

1. When engaging a gear after start up it usually engages with a jolt, sometimes just a little one, sometimes more severe?

 

I occasionally had this and the 'thud' varied but it wasn't anything concerning. Not sure if this is normal but I'd imagine it would make some sort of mechanical noise.

 

2. When stationary (at traffic lights for example) and in D there is a vibration at just the right frequency to make the glovebox lid rattle, but If I go to P then all is fine.

 

Not the gearbox, check if it is idling low, possibly the cause of the vibrations and no it shouldn't vibrate that much.

 

3. It feels a little slow getting off the line but again I'm used to manual cars so have nothing to compare it to. Is this just the torque converter doing its thing?

 

Nope, should be pretty quick off the mark, maybe not as quick initially off the line as you can hit the revs and dump the clutch in a manual.

 

Does the above sound normal? I am planning on changing the fluid, I've read that. Removing the sump plug will allow to remove just 2 litres, but to do a full fluid flush is a lot more involved and probably best left to an expert. Would the 2 litre change make a noticeable difference? How much does a full flush cost?

 

 

1. When engaging a gear after start up it usually engages with a jolt, sometimes just a little one, sometimes more severe?

 

I occasionally had this and the 'thud' varied but it wasn't anything concerning. Not sure if this is normal but I'd imagine it would make some sort of mechanical noise.

 

2. When stationary (at traffic lights for example) and in D there is a vibration at just the right frequency to make the glovebox lid rattle, but If I go to P then all is fine.

 

Not the gearbox, check if it is idling low, possibly the cause of the vibrations and no it shouldn't vibrate that much.

 

3. It feels a little slow getting off the line but again I'm used to manual cars so have nothing to compare it to. Is this just the torque converter doing its thing?

 

Nope, should be pretty quick off the mark, maybe not as quick initially off the line as you can hit the revs and dump the clutch in a manual.

 

 

Not sure on the fluid side, I was advised not to do a full flush unless something was wrong. Have you checked the gearbox oil using the dip in the bay?

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1. I get a slight thunk engaging D or R but only from cold when the autochoke is holding higher revs. When settled there's nothing.

2. Vibration at idle could more likely be engine mounts. Mine used to vibrate like a good un until they were changed - not a thing now.

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I get 1&2 most of the time.

 

I presume the clunk is just the forward motion coming on while you still hold the brakes?

 

And with the rattle, would engines mounts be going in under 45000 miles? I have a tiptronic and don't think the rattle occurs in the low gears rather than D?

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After I bought my auto BPU'd RZ-S I found that it refused to change up at full throttle, this turned out to due to a faulty speed converter but planted the seed of doubt in my head as I have very little knowledge or experience of automatic transmissions. Are the following normal?

 

1. When engaging a gear after start up it usually engages with a jolt, sometimes just a little one, sometimes more severe?

There's a big, rubber donut connecting the prop to the diff, check thats not toast.

 

Also, if theres any doubt as to an auto box's operation first port of call should be a full fluid flush.

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There's a big, rubber donut connecting the prop to the diff, check thats not toast.

 

Also, if theres any doubt as to an auto box's operation first port of call should be a full fluid flush.

 

Is a full fluid flush a DIY job or best left to a good garage? Any idea on cost?

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That's what I was told but again like others have said...Apparently it's bad to change the whole fluid unless there's something seriously wrong like a rebuild. God knows why. Surely all new fluid is always going to be a good thing????

 

I agree, we wouldn't change just a litre of our engine oil after-all. Plus I'm guessing I've still got the original transmission fluid in my box so surely it is long overdue a complete flush.

 

I can't remember the exact reasons why but it was something to do with iron fillings or substance in the gearbox transmission? It was quite a long time ago I asked this and to be honest the garage didn't specialise in Supra's, they just recommended not to completely flush the system unless something was really bad on the box. I was thinking along the same lines as you guys that like an engine oil it would be a good idea to flush the system. Hopefully someone with more knowledge on this can correct us on this.

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Fluid is very dark so agree it's long overdue. Can anyone recommend a garage in the midlands and any idea of the price? I'll have to look into engine mounts by the sounds of it too. :blink:

 

If you are in the Midlands then I'd recommend Garage 786, owned by AshBhp on this very forum:

 

http://www.garage786.co.uk/

 

 

With regards to the engine mounts only the facelift Supra's seemed to be effected by this, is yours a facelift?

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