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I've been away in Queensland this week with a Pajero Sport hire car and just gave it back.
This gave me a great chance to play with an understand the new 8 speed transmission, and to see if it would benefit from developing a lockup-mate for it.
Here are my observations.
My first impression was the gear changes were very noticeable - as also observed in this thread
I spent a lot of time understanding when the transmission locked up and when it didn't.
My testing was done in SPORT mode, 2H. No testing in 4H or 4LLc.
Here are my conclusions:
1. it doesn't lockup in 1st and 2nd gear at all
2. in 3rd to 8th gears it locks up at ~1900rpm, and stays locked until you drop revs to ~1200 RPM, even if you accelerate gently.
3. If you accelerate firmly between 1500 and 1900 RPM (in 3rd-6th) when locked, it will unlock (to give you power) and then re-lock again at about 2000-2400RPM depending on the accelerator pedal position.
4. When in 7th or 8th gear it doesn't do this. At low RPM (say 1300), it just stays locked if you accelerate firmly and you get very poor engine response. There is no shudder in the driveline like you'd get with a Gen4 Pajero
5. When you take you foot off the accelerator it unlocks. The moment you apply acceleration again it re-lock immediately. You see this as a little wobble on the tacho needle.
6. As you accelerate in DRIVE, you see the RPM drop significantly with each gear change (~400 RPM) and there is no torque converter slippage, So you also don't get that spongy auto feel either.
So the reason the gear shifts are not as smooth as a Gen4 Pajero or a Challenger is the 8 speed transmission is programmed to lockup the torque converter to eliminate the slippage.
In contrast, the Gen4 Pajero and challenger let the torque converter slip, which generates heat, uses more fuel...but make it smoother in operation.
So my lockup-mate/auto-mate products maximise torque converter lockup and make the Gen 4 Paj and the Challenger transmissions operate pretty much the same as the 8 speed transmission in the Paj Sport. This is comforting
With the 8 speed Pajero Sport you get all the benefits of lower transmission temperatures and better fuel economy, BUT, the gear changes are more noticeable. ie not 'as smooth'
I think this answers the question people often ask about why didn't they just lockup the torque converter like they should have from factory.....because if they did, some people don't like it because it's not as smooth. With a 5 speed transmission the spacing of gear ratios are wider hence is even more noticeable than in a 8 speed.
People expect an auto transmission to be silky smooth and the slipping torque converter allow this feeling.
In the Pajero Sport it works more or less like a clutchless manual, and this just takes a little getting used to. It's not bad, just different...and in my opinion better.
Will I develop a lockup-mate for a Pajero Sport? No.
It is already programmed correctly and will give better fuel economy and lower transmission temperatures than if they'd let the torque converter slip more.
I reckon you can tow with confidence in a Pajero Sport that you're not going to overheat the transmission.
Wouldn't mind hearing the opinions from PS owners though.
Hmmm...should I develop an unlockup-mate product to make the transmission smoother?
This gave me a great chance to play with an understand the new 8 speed transmission, and to see if it would benefit from developing a lockup-mate for it.
Here are my observations.
My first impression was the gear changes were very noticeable - as also observed in this thread
I spent a lot of time understanding when the transmission locked up and when it didn't.
My testing was done in SPORT mode, 2H. No testing in 4H or 4LLc.
Here are my conclusions:
1. it doesn't lockup in 1st and 2nd gear at all
2. in 3rd to 8th gears it locks up at ~1900rpm, and stays locked until you drop revs to ~1200 RPM, even if you accelerate gently.
3. If you accelerate firmly between 1500 and 1900 RPM (in 3rd-6th) when locked, it will unlock (to give you power) and then re-lock again at about 2000-2400RPM depending on the accelerator pedal position.
4. When in 7th or 8th gear it doesn't do this. At low RPM (say 1300), it just stays locked if you accelerate firmly and you get very poor engine response. There is no shudder in the driveline like you'd get with a Gen4 Pajero
5. When you take you foot off the accelerator it unlocks. The moment you apply acceleration again it re-lock immediately. You see this as a little wobble on the tacho needle.
6. As you accelerate in DRIVE, you see the RPM drop significantly with each gear change (~400 RPM) and there is no torque converter slippage, So you also don't get that spongy auto feel either.
So the reason the gear shifts are not as smooth as a Gen4 Pajero or a Challenger is the 8 speed transmission is programmed to lockup the torque converter to eliminate the slippage.
In contrast, the Gen4 Pajero and challenger let the torque converter slip, which generates heat, uses more fuel...but make it smoother in operation.
So my lockup-mate/auto-mate products maximise torque converter lockup and make the Gen 4 Paj and the Challenger transmissions operate pretty much the same as the 8 speed transmission in the Paj Sport. This is comforting
With the 8 speed Pajero Sport you get all the benefits of lower transmission temperatures and better fuel economy, BUT, the gear changes are more noticeable. ie not 'as smooth'
I think this answers the question people often ask about why didn't they just lockup the torque converter like they should have from factory.....because if they did, some people don't like it because it's not as smooth. With a 5 speed transmission the spacing of gear ratios are wider hence is even more noticeable than in a 8 speed.
People expect an auto transmission to be silky smooth and the slipping torque converter allow this feeling.
In the Pajero Sport it works more or less like a clutchless manual, and this just takes a little getting used to. It's not bad, just different...and in my opinion better.
Will I develop a lockup-mate for a Pajero Sport? No.
It is already programmed correctly and will give better fuel economy and lower transmission temperatures than if they'd let the torque converter slip more.
I reckon you can tow with confidence in a Pajero Sport that you're not going to overheat the transmission.
Wouldn't mind hearing the opinions from PS owners though.Hmmm...should I develop an unlockup-mate product to make the transmission smoother?
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