C

Chippyray

Member
I am a new member and thanks to all the info supplied on here have, had a great time with my new vehicle. I have a strange question which hopefully someone on here can answer. I bought my truck a 1999 ES td5. I have changed various bits and pieces thanks to the members on here who have supplied lots of tips and info on the various forums. I serviced my auto box over the last few weeks, changed the oil, ran it for a few hundred miles and then changed the oil and filter. The gear box has improved dramatically. And here is the odd thing. It starts out in first go's through the gears to fourth as it did before but much smoother, On reaching about 55mph the revs drop and it feels like it has a fifth gear or over drive. In my youth I was always doing up cars mainly fords and would often change gear boxes and diffs. Because of the swapping about the speedos were often incorrect but I could always tell how fast I was going in top gear, as it was direct drive. 2000 revs would be forty, 3000 sixty etc. When my motor is in fourth it is direct drive and complies with the last statement. Once it settles in, the revs at sixty are reading just over 2000 revs maybe 2250. It feels like a gear change and rev counter suggests the same.
My question is, am I going barmy, is this normal or has one of the previous owners put in a different box. Any help, advice and or opinions would be much appreciated.
 
IMO a different gearbox would have not worked with the Td5's management but there are cases when owners change the autobox ECU with a V8 ECU for different gear change pattern and there are cases when that's good and others when not, many factors are involved as the autobox ECU is addaptive, read the p/n from the EAT ECU(under the passenger seat) and put it here and i'll tell you
 
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Chippyray said:
Sorry mate not quite sure what you mean. Could you explain please
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Hit Google.

A single post reply is not sufficient to explain how an automatic transmission works. So you are probably better doing some research.

But essentially they all use a torque converter. Which is a liquid/viscous coupling. More modern autos from the last 20-25 years normally electronically lock up and remove the slippage from the viscous coupling. This is perfectly normal.
 
TD5 auto has 4 forward gears plus the torque converter can be made to lock up. Aim of lockup is to provide direct drive at cruising speeds, thus removing viscous losses and achieve greater fuel economy.

TD5 should lock up at 52mph or thereabouts in 4th gear with selector in 'D'. It can also lock up in 3rd with selector in '3' at somewhat lower speed.

Lockup 'feels' like you describe - revs will drop and - importantly - there won't be any slip between engine and transmission until you drop out of lockup.

Fun fact: TD5 transmission management has a bit of hysteresis built in, so you can blip to 52mph to pick up lockup and then carefully back off the throttle and cruise as low as 1700 revs.

Which may or may not be popular with other road users, depending on the road ...
 
Apologies for short response above - others have provided more fulsome compared to my single line! My bigger answer would have been pretty much in line with @300bhp/ton and @joojar - but without the use of the word "hysteresis"
 
joojar said:
TD5 auto has 4 forward gears plus the torque converter can be made to lock up. Aim of lockup is to provide direct drive at cruising speeds, thus removing viscous losses and achieve greater fuel economy.

TD5 should lock up at 52mph or thereabouts in 4th gear with selector in 'D'. It can also lock up in 3rd with selector in '3' at somewhat lower speed.

Lockup 'feels' like you describe - revs will drop and - importantly - there won't be any slip between engine and transmission until you drop out of lockup.

Fun fact: TD5 transmission management has a bit of hysteresis built in, so you can blip to 52mph to pick up lockup and then carefully back off the throttle and cruise as low as 1700 revs.
joojar said:
TD5 auto has 4 forward gears plus the torque converter can be made to lock up. Aim of lockup is to provide direct drive at cruising speeds, thus removing viscous losses and achieve greater fuel economy.

TD5 should lock up at 52mph or thereabouts in 4th gear with selector in 'D'. It can also lock up in 3rd with selector in '3' at somewhat lower speed.

Lockup 'feels' like you describe - revs will drop and - importantly - there won't be any slip between engine and transmission until you drop out of lockup.

Fun fact: TD5 transmission management has a bit of hysteresis built in, so you can blip to 52mph to pick up lockup and then carefully back off the throttle and cruise as low as 1700 revs.

Which may or may not be popular with other road users, depending on the road ...
Click to expand...
Thank you very much for the reply I am not a motor engineer but can understand what you mean. It explains everything quite nicely.
Click to expand...
 
GJ1 said:
Apologies for short response above - others have provided more fulsome compared to my single line! My bigger answer would have been pretty much in line with @300bhp/ton and @joojar - but without the use of the word "hysteresis"
Click to expand...
I understood everything he said and read hysteresis as mug. In my terms I can take it up to 52 let the torque converter do its thing and then drop back on the speed therefore mugging the system into believing I am still travelling at 52. The English used was much better than mine but I think we all got the meaning.

You guys on here are very helpful and I bow to all of your superior knowledge.
 
sierrafery said:
IMO a different gearbox would have not worked with the Td5's management but there are cases when owners change the autobox ECU with a V8 ECU for different gear change pattern and there are cases when that's good and others when not, many factors are involved as the autobox ECU is addaptive, read the p/n from the EAT ECU(under the passenger seat) and put it here and i'll tell you
Click to expand...
Hello mate, I am a newby and cannot find what I am supposed to look for under the passenger seat. All I can see is the amp for the radio/cd player. What exactly am I looking for. Please type slowly I'm not an mechanic just a wood butcher,
Thanks for your time.
 
sierrafery said:
The ECU should be beneath the amplifier and it has a bigger multiplug in it
Click to expand...
Thanks for that. I think I now have a handle on what is happening thanks to Joojar's explanation. But I will still get the info you asked for as I would feel ungrateful if I didn't listen to your advice. It will probably be over the weekend all being fine time wise. Thanks again for your help and advice.
I looked at a lot of websites before taking the plunge and buying a truck. From what I can tell those who can use spanners love them. It's those who can't that give these motors the bad press. I am so pleased I bought this truck, it has given me another hobby. I get a lot more help and advice from this forum than I ever did when I was young fella playing with Anglias.
 
Chippyray said:
But I will still get the info you asked....
Click to expand...
Don't bother with that as long as you are pleased, it was just an ideea in case if something was not OK, if you think everything works as it should after the explanatiions let the ECU alone and enjoy the ride :)
 
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