New to towing - jerking / tugging trailer - transmission damage?

[corbijn]

Hi All,

I am recently new to towing. We have a camper trailer (under 750kg) that is a basic single axel box trailer. We have a 2008 D3 with the factory hitch.

When we first got it 6 months ago I noticed some degree of tugging/bouncing/jerking. Not massive amounts but enough to be noticeable. This seemed to increase as we increased speed.

My understanding this movement could be related to

a) drawbar pointing slightly down.
b) poorly weighted trailer
c) suspension on the car
d) just normal and I am over playing it.

Happy to put up with it and continue to tweak the setup but I am worried it could cause damage? Some online reading has indicated jerking trailers can cause damage to the transmission. Over the last 6 months we have had a shudder that gradually got worse. A transmission fluid change seems to have fixed this for now.

Was this just a coincidence or could a jerky trailer have caused the issue?

Thanks for your help :)

[101RRS]

On the towing bounce - there was a thread about this about 4 to 6 weeks back but unfortunately the search function nor google is picking it up. In thread I indicated I get the same pitching and bouncing but most other respondents did not have the issue - some put it down to shocks but I know mine are OK - hopefully someone will have a link. I think it is a characteristic of air suspension but there are dissenting views.

The problem with your gearbox sounds like a failing torque converter - delayed (and hopefully fixed) by your fluid change. Unlikely to be related to what you tow as it is light but again there are a few here have actual similar experiences and should comment.

Garry

[DiscoJeffster]

When I first towed a trailer on my D4 I was quite disturbed. It definitely makes the car feel quite different. The trailer does impart some movement back into the car as it hits bumps and things. I've gotten used to it but I had a similar experience when I started out.

[corbijn]

Thanks both for your feedback :)

The "feeling" is not horrendous and I am only really worried if it is causing damage. I will try a few tricks about balancing and get my ball height looked at (sounds awkward).

Thanks again :)

[Chops]

Bouncing when towing (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/251386-bouncing-when-towing.html)

I think this is it.

[corbijn]

Bouncing when towing (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/251386-bouncing-when-towing.html)

I think this is it.

Thanks! Will read through this :)

[DiscoMick]

Towing a weight will obviously make a difference, but it shouldn't cause a lot of tugging. Driving style can be a factor. Try to keep throttle and brake movements smooth and gentle and see if that makes any difference.
A transmission service was a good idea, as it can be neglected. As well as changing the oil, did they replace any filter in the gearbox? Some transmissions have an internal filter which can be neglected, block up and affect the operation.

[101RRS]

Bouncing when towing (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/251386-bouncing-when-towing.html)

I think this is it.

Yes that is it - I commented in that thread and yet when I do a search of my own posts by author, posts older than one month the "Bouncing when towing" does not come up - admins might want to look at that.

Garry

[vee8auto]

Independent Land Rover specialist in Perth told me to always use Sports Mode on the auto when towing. Always.

[corbijn]

Independent Land Rover specialist in Perth told me to always use Sports Mode on the auto when towing. Always.

That's interesting. Does keeping the revs up help?

[Tombie]

It doesn’t keep the revs up. Just makes the transmission more responsive.

[vee8auto]

That's interesting. Does keeping the revs up help?

Yes, but thats not the main reason.

If I recall correctly the main reason is because it applies more pressure to the clutch plate assembly thingy and prevents slippage and extra wear from the heavy load. Perhaps that rings a bell with someone who knows the 6 speed box.

So whenever I know its working hard, towing, or steep windy bits, etc, I put in sport mode.

[Milton477]

Maybe there is some play in the hitch. If you have ever towed something with override brakes you would have felt the back & forward pushing & tugging as the hitch slides back & forward activating the brakes. Does the hitch fit snugly on the 50mm ball if that is your system?

[Tombie]

Are we sure it’s jerking/tugging? Or just a pitching sensation?

A small trailer shouldn’t be throwing it around more than rise and fall...

[corbijn]

Are we sure it’s jerking/tugging? Or just a pitching sensation?

A small trailer shouldn’t be throwing it around more than rise and fall...

Yeah it is hard to describe the sensation, particularly when I have no idea what normal is. I will try to think of a way of describing it.

[discorevy]

Check the tacho when it happens, do the revs fluctuate?, as mentioned, the torque converter could be the problem, towing in sport mode keeps it in 5th , and will lock the converter ( as opposed to regulated which can cause the clutch in the converter to slip due to age / wear / glazing) its much kinder to the trans.

[Tombie]

Towing in sport mode does not keep it in 5th.
It just enables quicker kick down and holds longer.

[101RRS]

Yes, but thats not the main reason.

If I recall correctly the main reason is because it applies more pressure to the clutch plate assembly thingy and prevents slippage and extra wear from the heavy load. Perhaps that rings a bell with someone who knows the 6 speed box.

So whenever I know its working hard, towing, or steep windy bits, etc, I put in sport mode.

No that is not correct - Sport is no different to normal drive except the gearbox uses a different program that changes the shift points and hangs on to each gear a little longer - that is why some people think that 6th is disabled as it takes a little while to get into 6th in Sport - it just hangs onto 5th for a bit longer that is all.

The advantage in using Sport for towing is that at any given time because it hangs onto gears a bit longer the gearbox is likely to be in one lower gear than normal in undulating conditions which is more suited to towing.

garry

[vee8auto]

No that is not correct - Sport is no different to normal drive except the gearbox uses a different program that changes the shift points and hangs on to each gear a little longer ......
garry

in the context that the original poster has queried transmission damage because something funky is going on when towing I thought it would be worth mentioning the advice for towing given by a Land Rover specialist. So unless another person, a guru level transmission dude who specialises in the internal workings control functions of that particular 6 speed auto box comes along and refutes or clarifies the advanced functions I reckon it should be considered a likely factor.

Sure, it might be furphy, I might have got my wires crossed, but as my previous career was as a specialist on industrial gas turbines and all their electronic, pneumatic and hydraulic systems I am fairly confident that I understood what the guy was telling me and I reckon what he said made sense.

[101RRS]

You might have understood what was said but it is crap - what he might have been talking about is the speed that "sport" locks the torque converter vs normal "drive".

[vee8auto]

can you elaborate on the "its crap" statement.

[Guss]

Do you have enough weight on the draw bar? If the draw bar is lifting at the tow bar you will get undesirable affects

[corbijn]

Do you have enough weight on the draw bar? If the draw bar is lifting at the tow bar you will get undesirable affects

I actually have no idea how much weight there is. I do know that I was concerned about putting too much weight on the drawbar so may have been erring too far.

I am heading off for the weekend. I will try and find a measurement.

I will create a list of what I will be adding too.

Cheers

[DiscoMick]

Should aim for about 10 percent of the trailer weight on the drawer.

[DI5CO]

I personally think you are better to take it to a Land Rover mechanic while towing the trailer, taking them for a drive and asking if it's normal. Too hard to diagnose a "fault" that may or may not be there on a forum.

[discorevy]

Towing in sport mode does not keep it in 5th.
It just enables quicker kick down and holds longer.

The op has a d3 , unless the d4 six speed has different TCU programming then I will stick with my statement that it will keep 5th in sport mode , I have an sdv6 6 speed coming in tomorrow so I will find out, until then you might want to let us know at which speed / load yours drop into 6th at when in sport mode.



in the context that the original poster has queried transmission damage because something funky is going on when towing I thought it would be worth mentioning the advice for towing given by a Land Rover specialist. So unless another person, a guru level transmission dude who specialises in the internal workings control functions of that particular 6 speed auto box comes along and refutes or clarifies the advanced functions I reckon it should be considered a likely factor.

Sure, it might be furphy, I might have got my wires crossed, but as my previous career was as a specialist on industrial gas turbines and all their electronic, pneumatic and hydraulic systems I am fairly confident that I understood what the guy was telling me and I reckon what he said made sense.


You are right to tow in sport mode , as well as listening to your lr specialist ( especially if it happens to be Kevin from rovertech) I worked with him for a few years a long time ago, I'm by no means a guru on zf ( I've only done one rebuild)

[DiscoJeffster]

So all the talk of the gearbox selecting a better program when a trailer is detected is moot then if you STILL have to select sports mode to tow. I think all this is wives tales and personal preferences to be frank. The car was designed to tow. If any of this was required it's more than capable of doing it all automatically without us having to select any of it.

[corbijn]

I personally think you are better to take it to a Land Rover mechanic while towing the trailer, taking them for a drive and asking if it's normal. Too hard to diagnose a "fault" that may or may not be there on a forum.
Yes :) That sounds very sane - just try to stop my brain thinking about it until I can get it to the mech :)

[101RRS]

The op has a d3 , unless the d4 six speed has different TCU programming then I will stick with my statement that it will keep 5th in sport mode , I have an sdv6 6 speed coming in tomorrow so I will find out, until then you might want to let us know at which speed / load yours drop into 6th at when in sport mode.

A six speed has the full range in gears in sport mode - it is only the shift points and the time it hangs on in gear that changes and this applies to 5th in Sport mode - it hangs on to 5th for a long time before it goes into 6th.

Try driving on a freeway at a steady 100kph in sport mode - after you have been in 5th for about a minute or so and driving at a steady speed it changes up to 6th - I have seen the specific specs sometime back but it is something like 10o kph and a minute or two.

I have had a 2.7TDV6 with ZF 6 speed for 7 years and 140,000km and I can assure you it goes into 6th in Sport mode and it does it when I am towing my camper in the right conditions.

Garry

[BobD]

I have been towing 2.5t around Australia for the last three months and the car most definitely goes into sixth gear in sports mode. At a constant 100 kph there is no difference between sports and normal. At 90 it usually holds fifth in sports mode unless going down hill, although on steeper down hills it will drop to fifth for a little more engine braking.

I have been towing in sports mode for the last two months but for the last four years have always left it in drive, with no issues. The best thing about sports mode is that it changes down to the lowest possible gear when braking heavily, which is very helpful when towing. With all the hills in NSW it is also good to hold the lower gears much longer on steep hills, as sports mode does.

I know Kevin recommends sports mode for towing heavy caravans but I've never heard him say anything about higher transmission clutch pressures and my car is there quite often lately. We have had lots of chats about trips and Discos in those visits.

[discorevy]

A six speed has the full range in gears in sport mode - it is only the shift points and the time it hangs on in gear that changes and this applies to 5th in Sport mode - it hangs on to 5th for a long time before it goes into 6th.

Try driving on a freeway at a steady 100kph in sport mode - after you have been in 5th for about a minute or so and driving at a steady speed it changes up to 6th - I have seen the specific specs sometime back but it is something like 10o kph and a minute or two.

I have had a 2.7TDV6 with ZF 6 speed for 7 years and 140,000km and I can assure you it goes into 6th in Sport mode and it does it when I am towing my camper in the right conditions.

Garry


I have been towing 2.5t around Australia for the last three months and the car most definitely goes into sixth gear in sports mode. At a constant 100 kph there is no difference between sports and normal. At 90 it usually holds fifth in sports mode unless going down hill, although on steeper down hills it will drop to fifth for a little more engine braking.

I have been towing in sports mode for the last two months but for the last four years have always left it in drive, with no issues. The best thing about sports mode is that it changes down to the lowest possible gear when braking heavily, which is very helpful when towing. With all the hills in NSW it is also good to hold the lower gears much longer on steep hills, as sports mode does.

I know Kevin recommends sports mode for towing heavy caravans but I've never heard him say anything about higher transmission clutch pressures and my car is there quite often lately. We have had lots of chats about trips and Discos in those visits.



Good feedback, thanks , its possible I haven't been towing my boat ( 2 tonne )over 100 kph , will try it out tomorrow.

[scarry]

So we have hired a van,weighs around 2100KG,and done 600 k so far today.
Vehicle is also loaded.I have never towed more than a small trailer with this vehicle before.

I found that with the vehicle in sports mode it won't change to sixth until at least 100km/hr, and usually only going down hill or on light throttle.

In D it will hunt between 5th and 6 th depending on hills,where in sports mode it will just happily sit in 5th,until a big hill comes along,then it will change back.

Once on the flat,that is west of Inglewood,on cruise,at 90km/hr actual it will sit in 5th all the time whether in sports or normal mode.

Note mine is 2.7l not 3.0l.

[Tombie]

The op has a d3 , unless the d4 six speed has different TCU programming then I will stick with my statement that it will keep 5th in sport mode , I have an sdv6 6 speed coming in tomorrow so I will find out, until then you might want to let us know at which speed / load yours drop into 6th at when in sport mode.





You are right to tow in sport mode , as well as listening to your lr specialist ( especially if it happens to be Kevin from rovertech) I worked with him for a few years a long time ago, I'm by no means a guru on zf ( I've only done one rebuild)

You can certainly keep your statement if you wish [emoji6]
And I can happily keep mine - we have a D4 and a D3 in the family, and the 6 Speed will Shift up once it’s not labouring (sufficient speed v revs).

We tow above 100 regularly (can tow at 110 where posted in SA) and they both shift up.
The loads are always 1800-2600kg

[discorevy]

So , today I managed 12 kilometres (about 7 minutes) at 110 kph in sport mode before having to slow down , car stayed in 5th the whole distance ( no trailer) 2005 tdv6

Could only get 2 minutes with mates 2012 sdv6 at 110 before having to slow down ( it stayed in 5th) so not conclusive, will check later

I'm not sure if there is a difference between tcu's from different year / models, would be good if others could report to add to the collective knowledge.

[BobD]

I assume that the dashboard display is saying S and not 5. If it is saying 5 it will not change as fifth has been selected.

[discorevy]

You assumed correct Bob, I also use the gap interface with gear selected , torque converter status ,amongst others, drove to Perth today , managed 28 kilometres at 110 without having to slow down ( not towing ) in sport mode , stayed in 5th , selected normal drive mode after that as it wouldn't be changing up after that distance, trans is in good shape

[BobD]

Discorevy, all I can say is that your car behaves very differently from my car and Tombie's cars as well as my son's D3, which all change to sixth in sports mode but at a higher speed of around 100kph.

[101RRS]

Yep - was on the highway today and thought of this thread and tried it - 100kph is the cutoff speed - below 100kph in Sport it stayed in 5th - above it changed to 6th - every time. I confirmed it was in 6th by changing in to normal drive and revs did not drop - if at just above 100kph in 6th drive and changing to sport it changes back to 5th but then straight back to 6th - at 110kph switching between modes may no difference and stayed in 6th.

I might suggest that your box has an issue or in fact you were in 6th in Sport.

Garry

[DiscoJeffster]

Same. I tried it today. Was in 6th D at @110kph. Switched to sport, no change. Accelerated in sport from standstill. Went into 6th. I wasn't towing anything so not sure if that makes a difference. Gear selection is also load related so I guess if a vehicle is experiencing more load it may stay in 5th.

[discorevy]

Thanks for confirmation, I can only think either software issue or maybe the pre updates all do this, anyone with an 05 tried this ?, the only thing mine has different from standard is a bas remap.

[BobD]

It might be the remap messing with things so that the transmission thinks there is more power being used perhaps?

Anyway, it doesn't really matter as long as it will go into sixth normally in D. Towing in fifth at 100 is not a bad thing.

[Tombie]

Thanks for confirmation, I can only think either software issue or maybe the pre updates all do this, anyone with an 05 tried this ?, the only thing mine has different from standard is a bas remap.

What about your wheels / tyres? How OS are you?

[101RRS]

Thanks for confirmation, I can only think either software issue or maybe the pre updates all do this, anyone with an 05 tried this ?, the only thing mine has different from standard is a bas remap.

Mine has a BAS map and is pre update and does what it is supposed to do.

[shanegtr]

Thanks for confirmation, I can only think either software issue or maybe the pre updates all do this, anyone with an 05 tried this ?, the only thing mine has different from standard is a bas remap.
I got an 05 D3 and it will drop into 6th in sport under light loads as others have described

[Tombie]

Discorevy- run an ECU analysis using the GAP tool and see what firmware you’re transmission is running...

[Rextheute]

I will preface by stating my RRS is at present having the box replaced .

This is is okay I accept they wear out .......

however , I know it has towed for thousands of kilometres .

i have a camper trailer 910 kg loaded ready to go 115kg on the ball .
Tows fine (towed ) in either drive or sport 110kmh in 6 - would shift down and accelerate quite happily , once throttle was released would lock up in 6

also so have a caravan 1480kg loaded 125kg on ball . This also towed fine in drive , but was better in sport mode ,would lock in 5th at approx 100km 6th gear not always locking up unless on the flat or backed off throttle .

However , the fault became more apparent as the incline progressed . The tachometer would float at approx 1900rpm ( torque converter failing )
It then would fault and lock in 3rd gear
Then final step was it lost e clutch - and then final drive .

This is is a cautionary tale , the gearbox oil was not changed , I flushed and drained - this helped , but only slowed the demise down

Land Rovers are great tow rigs , I have a lot of experience in towing and would recommend a LR over any other vehicle , strong ,stable and very predictable handling .Adequate power which makes it easy and with minimal stress .

There is a lot of LR experience on this forum , not always in agreement !

With regard to the 'tugging '

I have had a couple of Land Rovers and none have done what you have describe , I also tow with an XC70 ,a Triton and a truck .
The fellas I work with have a Hilux and a Colorado - both tow campers and caravans neither have experienced the symptoms described .
i would be checking your weights ( tare and ball ) and your loading , both vehicle and trailer , and running some back to back testing over the same section of road , you may want to check tyre pressures also .
And don't use a weight distribution hitch , it will freak the car out - I have tested this with my caravan - I cannot tell you why but it doesn't like it !

Sorry a a bit long , if any of this has been covered - ignore me !

But these are very capable vehicles .
Check everything ,and then go back to basics .

cheers

[Chops]

Excellent bit of info RTU, thanks.

[Guss]

Does the trailer have LED lights?

My caravan has LED lights and when the van is attached I don't get the trailer light symbol flashing on the dash, so I assume it is not aware of the van. Once I add a resistance load to the circuit the trailer light symbol is displayed.

I had a resistor load box for my D3 and use it on the D4.

I'm not sure if this makes any difference to the way the vehicle opperates, but might be worth trying.

[discorevy]

It might be the remap messing with things so that the transmission thinks there is more power being used perhaps?

Anyway, it doesn't really matter as long as it will go into sixth normally in D. Towing in fifth at 100 is not a bad thing.

Yep probably doesn't matter , but I'm just curious


What about your wheels / tyres? How OS are you?

265/70/17 dynapro , so 5% larger , speedo error is now less than 1%



Discorevy- run an ECU analysis using the GAP tool and see what firmware you’re transmission is running...

Hardware thc500012
Calibration 5h22-75105-ca
Assembly 5h22-7z366-ca
Strategy 5h22-7j104-aa
While updates are available for my e diff and terrain response , none I can see are available ( through gap ) for transmission

[corbijn]

I will preface by stating my RRS is at present having the box replaced .


Sorry a a bit long , if any of this has been covered - ignore me !

But these are very capable vehicles .
Check everything ,and then go back to basics .

cheers

Not to long at all! Thanks for the info.

We took out the camper on the weekend and really only noticed some "feeling" from the trailer at around 90kmh. Not even sure if it is exactly tugging.

I am going to check the tyres are balanced on the trailer first. I will then see how she feels.

I will also take her to my mechanic who toes a great deal with LR's and see what he says.

From there. Probably play around with the weights etc.

Thanks all for your input :)