Techniques for towing vans up hills

[Luke68]

TC lock up

Thanks Old Jack. That is the best and most simplest explanation that anyone has given. Sorry for the "off the cuff" comment. I'm coming from a manual only 4wd so don't really understand these automatics. I've seen too many people do mods on their vehicles because they think it's the best thing ever. Hence my "off the cuff" comment.
Now, can you please let me know if this lockup mod will help in the auto retardation down hills if still locked up?
I'll be towing a caravan/camper later in the year and would like To get it fitted if it does a good job?
I know I can't compare Manual V Auto with braking.
Cheers
Luke

[old Jack]

Thanks Old Jack. That is the best and most simplest explanation that anyone has given. Sorry for the "off the cuff" comment. I'm coming from a manual only 4wd so don't really understand these automatics. I've seen too many people do mods on their vehicles because they think it's the best thing ever. Hence my "off the cuff" comment.
Now, can you please let me know if this lockup mod will help in the auto retardation down hills if still locked up?
I'll be towing a caravan/camper later in the year and would like To get it fitted if it does a good job?
I know I can't compare Manual V Auto with braking.
Cheers
Luke

Hi Luke,

A locked torque convertor does provide a reasonable amount of engine braking when going downhill and it also circulates the ATF through the ATF cooler so you get a decrease in ATF temperature. The factory program has the TC unlocked when going downhill so the ATF temperatures do not decrease until you are on the flat and the TC locks up so in hilly terrain where the factory TC remains unlocked for extended periods of time so the ATF just gets hotter and hotter. The Challenger is my first auto 4wd after 30+years of manual 4wds, whilst I really appreciate the auto's torque multiplication effect off-road which compensates for the high low range gearing and the flat spot/turbo lag of a CRD engine the auto's electronic control has had me frustrated since new and I have been looking for a solution. What I really wanted is an AT ECU reprogram but this has proved impossible to achieve. MM4x4 Lockup-Mate piggy back ECU goes a long way to fixing most of the issues with the AT and Auto-Mate should fix even more.

OJ.

[&Roo]

Hi Old Jack

Thanks for the explanations - I’m in a pretty steep learning curve in this space and they’ve been a great help.

I received my ultraGuage a few days ago and am now watching trans temps as I drive getting a feel for shift patterns that will look after the AT.

My big question ... other than sound and feel. Is there a way I can tell when the TC is locked vs. unlocked?


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[old Jack]

Hi Old Jack

Thanks for the explanations - I’m in a pretty steep learning curve in this space and they’ve been a great help.

I received my ultraGuage a few days ago and am now watching trans temps as I drive getting a feel for shift patterns that will look after the AT.

My big question ... other than sound and feel. Is there a way I can tell when the TC is locked vs. unlocked?


Sent from my iPhone using Tapatalk

Unless you have a TC indictor like Lockup-Mate does or a voltmeter connected to the AT ECU you can have trouble detecting when the TC is locked or unlocked. Vehicle speed vs rpm for a given gear is the next best indicator. In 4th gear 80kph/2140rpm, 100kph/2670rpm, 110kph/2940rpm and in 5th gear 100kph/1950pm, 110kph/2150rpm and the TC is locked up( there will be some minor variance to these numbers depending on speedo accuracy, tyre wear and tyre pressures. When the TC unlocks then rpm will increase several hundred rpm and is often mistaken for an automatic gear down shift. ATF temps will also increase at least 15C within a short time and continue to increase the longer the TC is unlocked. These figures are for a NT,NW and early NX with standard diameter tyres and 3.917 diff ratios.

OJ.

[m_and_m]

Hi Old Jack
My big question ... other than sound and feel. Is there a way I can tell when the TC is locked vs. unlocked?

Another way to tell is to gentle push the accelerator little. If the RPM stays the same it's locked. If the RPM immediately starts to go up - the TCC is slipping so it's unlocked.

If you keep pushing the accelerator while it's locked, you suddenly notice it jump in RPM - this is it unlocking.

[m_and_m]

The 8 speed Aisin auto in the Pajero Sport, already locks the TC in 3rd, 4th, 5th, 6th, 7th and 8th gear and the TC lockup operational profile is quite complex so it could be very difficult to do a Lockup-Mate for this auto trans, it may not even be possible at all.

OJ.

Never throw out a challenge like that to an engineer
I reckon it's possible. It might actually work quite well with all the extra gears to play with.

[old Jack]

Never throw out a challenge like that to an engineer
I reckon it's possible. It might actually work quite well with all the extra gears to play with.

Challenge on, after Auto-Mate is finished for the Challenger/Triton and then the Gen 4 Pajero. I have all the factory graphs of the gear changes up and down as well as the torque convertor lock up profiles, they are very complex. Also need access to a PS for testing.

OJ.

[Flying]

Never throw out a challenge like that to an engineer
I reckon it's possible. It might actually work quite well with all the extra gears to play with.

Also need access to a PS for testing.

OJ.

Happy to help if possible and when I'm in SA.

[cafey18]

We are towing close to the limit of 3T with an NT Platinum. Towing in the flat country in 5th keeping the converter locked as best as possible then shifting it to 4th prior to a hill and then 3rd if required. Regular trans oil changes with the new Penrite ATF LV (low viscosity) oil depending on how much towing your doing. 190,000km (30% towing) so far trouble free.
I have removed the inlet manifold and thoroughly cleaned all the power robing carbon muck build up and then also ran it with a professional inlet manifold cleaning solution to ensure even behind the valves are clean. Then fitted a catch can on the crankcase ventilation line to prevent the sludge build up again. No need to muck around with the EGR, it's fine left alone. I did remove the EGR system but it was quite clean due to running decarboniser every 10k. A full service and adjusted the valves plus replaced the timing chain tension guide between the cams up top. Then fitted a 2.5" full stainless exhaust system with a high flow CAT and a Rapid Chip Module tuned for torque. Just amazing how much torque is available now with better economy.
We live in central west NSW and our recent trip to Stockton Beach area towing through a mix of terrain with some very steep grades included returned 13.7 L/100km on the way down and 15.9 L/100km return. This was all at 100Kph and back to 80 Kph on the steepest grade. I had to drive the same route without towing and returned 8.1 L/100Kph at 100+ Kph.
Just love the improved torque but treat the transmission with respect and you will have trouble free towing.

[Pajez]

Nice to have improved torque