Disco 1 Adjusting torque converter lockup speed

Hi All

A question if I may about a 300tdi Disco with an automatic box. Perhaps an explanation first, I bought this https://www.landyzone.co.uk/land-rover/discovery-300tdi-5-door-auto.300836/#post-3801825 on body condition rather than with my choice of a manual gearbox, I thought I could convert it later. However in the past few months I have got more used to the auto, so much so that I ended up having a long trip in my mate’s 200tdi manual to give it a try. I must say that until I hit a traffic jam I was convinced that I would convert to manual, but my auto is just so much easier in traffic. So I need to solve the issue that drives me mad about the auto, the speed that the torque converter locks up. The 48 to 50 mph point is right at the speed I seem to spend a lot of time at on A roads with the result that it constantly hunts in and out of torque converter lock up.

I have done a search to see if this speed is adjustable but without success, however I found this old thread https://www.landyzone.co.uk/land-rover/quick-autobox-question.262246/#post-3152853 which seems to suggest that the gearbox should lock the torque converter at lower road speed in lever position 3 (edit I have just noticed it is a Range Rover thread) . I thought that this could be just what I want. But mine does not lock up in position 3. It does give good engine braking in 3 and 2 whilst giving a good free wheel in D. It always drops the revs by about 200 everytime I shift from 3 to D at constant throttle position and goes up by the 200 revs if I shift D to 3. Does this mean there is a “semi” lock up taking place? Is this what it is supposed to do or should it be a full lock up. It is definitely not a full lock up, locked up in D above 50mph and the speed always matches the revs so no slip, therefore a good TC?

Am I missing the point, is the lockup speed adjustable, or is my box faulty and not giving the TC the pressure to lock the clutch in 3?

Thanks for looking


David

D2 td5 locks up in 3rd but box is different off the top of my head

Thanks for answering, I guess the Range Rovers of the period had the D2 box. The D2 box is I think electronic.
Maybe Ashcrofts could answer if the speed can be adjusted.

David

Lockup should be a bit higher something around 53mph and drop out around 46-48 mph in normal driving, there's no lockup in 3rd.
The gearbox can be altered, Ashcroft's will do that for you to give you a lockup at a lower speed, but my RR locked up at around 45mph far to low for driving in the 40 50 Zone, come to a hill and I had to select 3rd or increase my speed which was not always appropriate.
With the lower power of a tdi I would think that a low lockup road speed driving would even be worse, maybe no I never driven an auto with a Diesel engine.

When was the fluid last changed? As that may sort out the "hunting" and because although u may feel and hear the box locking up you shouldn't notice the dropout just see the engine revs change but I'm speaking for a V8 auto, it's well know that the alto box is mor sited to th higher reving petrol engine.
Also shifting from 3 to D and the revs decrease only means you are now in 4th.
Road test procedures etc for the autobox are listed in RAVE if your interested.

Hello Tooarf, I asked the same question several years ago, at the time I was new to land rovers and my 300tdi auto would lock out at 52mph. I found out to change the lockout speed you have too change a spring that controls the hydropic activation pressure. Unfortunately this spring is located in the bowls of the gearbox, it's one of those jobs that when you take the box apart it's the second too last thing you remove. So unless your rebuilding your box it's a big job just too change the lockout speed. Stronger the spring the higher it changes, but be careful get it wrong and the box must come apart again. Now the road speeds have been lowered it can be a bit of a pain, but with practice it's manageable. I hope this has helped.

Thanks to both Zuggyland and Discool for your answers. I had not thought of rave, I will check that out.
The fluid I plan to change, I have not got around to it since I bought, it is however good and red, nice and runny, good smelling and on the full mark, hence its on the "round to it" list.

I had in my mind a lock speed of 40mph which I thought would suit my driving style, however I take the point about 45 being too low having one specific point will always be a compromise and never always perfect.

David

David, if you lock out your top gear to low it could cause excessive strain on the engine before it kicks down into third gear. It's a fine balancing act with an automatic. If it were a manual you would be wanting too change down all the time. You may end up having too change down manually anyway which is defeating the object of a automatic.

Happy motoring. Ray.

Hi Toonarf, I would be inclined to leave well alone. I'm lucky enough to have the best of both worlds with a 98 300tdi auto with EDC and a 94 200tdi manual. I've owned the 300 for four years now and to begin with like you I found it a little frustrating that it wouldn't change up at anything less than 52 mph but over time and 27000 miles I've completely got used to it and wouldn't dream of changing it. my wife and I have twice driven the old girl down through Europe to Greece and back involving lots of motorways but also plenty of mountain roads and the gearbox just sorts it all out for you without any fuss. Since owning it I've met the previous owner who lives locally and he explained that he also found it very frustrating, so much so that he traded it into the dealers that I bought it from, he's regretted it ever since and wishes he'd persevered with it. As for the old 200 manual, I've had that for about three years now and I love it but the 300 with an auto is so much more relaxed and actually slightly faster over a measured distance, not that they were ever meant to be fast.

Toonarf said:

Thanks to both Zuggyland and Discool for your answers. I had not thought of rave, I will check that out.
The fluid I plan to change, I have not got around to it since I bought, it is however good and red, nice and runny, good smelling and on the full mark, hence its on the "round to it" list.

I had in my mind a lock speed of 40mph which I thought would suit my driving style, however I take the point about 45 being too low having one specific point will always be a compromise and never always perfect.

David

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Not directly answering your question. But I guess you could try running different sized tyres, change the diff or transfer ratio. It won't change the lock up point exactly, but will affect the road speed it happens at.

Zuggyland said:

David, if you lock out your top gear to low it could cause excessive strain on the engine before it kicks down into third gear. It's a fine balancing act with an automatic. If it were a manual you would be wanting too change down all the time. You may end up having too change down manually anyway which is defeating the object of a automatic.

Happy motoring. Ray.

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Kick down from lock-up into third will only happen at arround 80mph, at lower speeds kick-down is two ratios therefore changing into second. So where's the "excessive strain"?

DiscoRay said:

Hi Toonarf, I would be inclined to leave well alone. I'm lucky enough to have the best of both worlds with a 98 300tdi auto with EDC and a 94 200tdi manual. I've owned the 300 for four years now and to begin with like you I found it a little frustrating that it wouldn't change up at anything less than 52 mph but over time and 27000 miles I've completely got used to it and wouldn't dream of changing it. my wife and I have twice driven the old girl down through Europe to Greece and back involving lots of motorways but also plenty of mountain roads and the gearbox just sorts it all out for you without any fuss. Since owning it I've met the previous owner who lives locally and he explained that he also found it very frustrating, so much so that he traded it into the dealers that I bought it from, he's regretted it ever since and wishes he'd persevered with it. As for the old 200 manual, I've had that for about three years now and I love it but the 300 with an auto is so much more relaxed and actually slightly faster over a measured distance, not that they were ever meant to be fast.

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Agreed. SWMBO and I both have D1 300's. Mine is auto, hers is manual. The manual (box) is going ASAP - a pal is breaking a D1 auto, and the box is going in SWMBO's.

I've upgraded my 300, with a full width intercooler, and tuned FIP.

Whilst there is nothing "wrong" with the R380 in SWMBO's D1 - we both find the auto far and away the better prospect.

As DiscoRay says - Stick with the auto - its worth it, well worth it in our opinion.

DiscoRay said:

I found it a little frustrating that it wouldn't change up at anything less than 52 mph

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Try using a lighter throttle and you will find you will be in 4th long before the 52mph lock-up speed.
And if you keep the pedal to the floor and in kick down and excelerate beyond the 52mph there won't be any lock-up and you will stay in 3rd... until you ease off. With my disco that could be 110mph.

Many thanks for all your replies; I was hoping that it could be a simple play about until you get a comfortable compromise sort of solution. But now knowing that it is deep inside the box that the adjustment needs making and that they all do that sir I will live with it.

I take the point about the engine not coping with a constant high torque requirement at lower revs, many years ago I drove an old ERF with a Gardner engine and a 2 speed axle, under the right conditions, high enough road speed, engaging the high ratio of the axle would give a galloping effect from the wagon, as if you had seamlessly shifted at least 2 gears higher but magically the engine suddenly had the power to pull them as well . A very weird feeling, and so similar to how my Disco feels when the torque converter locks up. In lock up if feels like it could take the world on. The trouble with the ERF was if you let the speed drop the engine then protested loudly, whilst in all other gears it felt very flexible and you could let the revs come right down.

The down side with the disco is it at “that” speed it is in and out like a fiddlers elbow. However mine is very definitely at 48mph with disengagement about 46mph so it sounds to be better than some anyway. I have also moved the kick down cable connection to the hole nearest the pivot on the pump, so more throttle opening before kick down. After a short run home today it seems a bit better.

I have driven many autos in the past but never owned one. I always used to stick them in D and leave well alone, however I now shift the stick often to suit road conditions, the free wheel is great sometimes but engine braking is available at the push of a lever, you don’t get that with a manual.

David

Well you could use the clutch pedal I guess...

300bhp/ton said:

Well you could use the clutch pedal I guess...

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LOL very true.

discool said:

Try using a lighter throttle and you will find you will be in 4th long before the 52mph lock-up speed.
And if you keep the pedal to the floor and in kick down and excelerate beyond the 52mph there won't be any lock-up and you will stay in 3rd... until you ease off. With my disco that could be 110mph.

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Sorry, maybe I didn't word it very well, what I meant to say was that the lock up at 52 mph took a bit of getting used to as I can't achieve it at any lower speed, no matter how light I am on the throttle. I'm almost always in fourth well before 52 mph, unless I'm having to accelerate hard for any reason and then as you say it hangs on to third until you back off a little. Wow your disco must be something a bit special to hang on to third to 110 mph, please tell us more. Mine is flat out at about 90 and I'm not sure I'd want to push it any further than that even if I could.

A light throttle won't change the 52mph lockup speed but u can bypass it by staying in kick down.
I usually ease off a 80 when in kick down and so the gearbox drops back in to lockup, then its upwards one onwards to 110 if the need ever requires it which is not often now as I don't use the disco that much (628miles between mot's this year) company cars take most of the strain now and they are a lot faster

As for the top speed of your vehicle, u have a Tdi so 90mph I believe is about right.

Ah I see, you must have a v8, really nice sound from that old lump, I had a Rover SD1 years ago and never tired of that gorgeous v8 burble.