D1 auto - overdrive kick in point

[nice1guv]

Hi, I have a 1996 D1 V8 auto.

The overdrive kicks in at pretty much exactly 80km/h.

Can this be changed to kick in at say 90km/h?

How hard is it to change?

[trobbo]

I just slip the t-bar between d & 3, particularily to change down to third for hills. Much easier and cheaper. :D

[RonMcGr]

Hi, I have a 1996 D1 V8 auto.

The overdrive kicks in at pretty much exactly 80km/h.

Can this be changed to kick in at say 90km/h?

How hard is it to change?

It changes hydraulically.
Therefore I don't like your chances :)

I'd love to be able to alter mine, as well.
It's a pity it was not electric of vacuum, then we could.:(

[nice1guv]

1996 V8 auto box: is this normal?

I have four normal gears plus the overdrive?

I regularly drive around in 3, manually changing to D (4th) at around 70km/h, then if I hit 80km/h it switches to overdrive.

[Romulus]

I just slip the t-bar between d & 3, particularily to change down to third for hills. Much easier and cheaper. :D

Ditto!
You took the words right out of my mouth! :)

[nice1guv]

Ditto!
You took the words right out of my mouth! :)

I do already use the shifter to shift down if needed, but this isn't what I'm after.

I want to get more out of 4th gear before it switches over to overdrive.

If you're giving it some in D, it will virtually go from 3rd to overdrive! with basically no 4th!

[B92 8NW]

I have four normal gears plus the overdrive

There is four forward gears, one of which is an overdrive.

It's not overdrive that's happening at 80 (it'll be in overdrive by 45 km/h under a light throttle (as per my Tdi)). What you're noticing is the lock up clutch in the torque converter engaging.

I think somewhere like A&B automatics in Dandenong can modify the governor to provide different lock up speed.

[SenatorKang]

There is four forward gears, one of which is an overdrive.

It's not overdrive that's happening at 80 (it'll be in overdrive by 45 km/h under a light throttle (as per my Tdi)). What you're noticing is the lock up clutch in the torque converter engaging.

I think somewhere like A&B automatics in Dandenong can modify the governor to provide different lock up speed.

That's what I thought.

Why do you want it to lock up later? I love that clutch. What I want is to be able to lock/unlock it on demand. Chuck it in 1, drive away, lock it up... unlock it, change to 2, lock it up... I assume you would have to unlock it when changing gears... edit: but still be able to keep it as normal when it's in D...

not sure what use it would have, but wouldn't it help fuel economy?

[nice1guv]

There is four forward gears, one of which is an overdrive.

It's not overdrive that's happening at 80 (it'll be in overdrive by 45 km/h under a light throttle (as per my Tdi)). What you're noticing is the lock up clutch in the torque converter engaging.

I think somewhere like A&B automatics in Dandenong can modify the governor to provide different lock up speed.

Ok, now I'm really confused.

Keep it below 80km/h and no overdrive or lockup clutch, hit 80 and it feels like another gear (like an electronic overdrive I had on another car) and the revs drop heaps.

On my car at least, it certainly doesn't happen at 45km/h under light throttle or at another speed - only 80km/h and above.

If you drop below 80 it kicks out and the revs go up. The car has more power before it kicks in at 80, so if I want to burn up a hill (on-road) at 90 it will be in " overdrive" and have not much power, if I manually shift it back to 3 then I'm in third and the revs are too high at 90. I want to be able to hold it in 4th with out it going to "overdrive".

[B92 8NW]

Ok, now I'm really confused.

Keep it below 80km/h and no overdrive or lockup clutch, hit 80 and it feels like another gear (like an electronic overdrive I had on another car) and the revs drop heaps.

On my car at least, it certainly doesn't happen at 45km/h under light throttle or at another speed - only 80km/h and above.

If you drop below 80 it kicks out and the revs go up. The car has more power before it kicks in at 80, so if I want to burn up a hill (on-road) at 90 it will be in " overdrive" and have not much power, if I manually shift it back to 3 then I'm in third and the revs are too high at 90. I want to be able to hold it in 4th with out it going to "overdrive".

Fourth gear is an overdrive as the ratio is 0.728:1.

On a V8 automatic the 3-4th shift according to the workshop manual occurs between 43-49 km/h on a light throttle 1430-1650 rpm.

Find a flat road, wind it up to 60km/h in D on a light throttle - shift back to 3, then back into D. Do it a few times - as you return to D each time, you will feel it picking up 4th gear which as stated above is an overdrive.

At 80km/h, the lock up clutch in the torque converter engages which feels like another gear as you say and the revs drop considerably. It will only lock up when in 4th (overdrive) gear.

The issue of having not enough power on hills when its locked up and over revving in 3rd is an inherent problem with these gearboxes.

[DiscoDan]

Ok, now I'm really confused.

Keep it below 80km/h and no overdrive or lockup clutch, hit 80 and it feels like another gear (like an electronic overdrive I had on another car) and the revs drop heaps.

On my car at least, it certainly doesn't happen at 45km/h under light throttle or at another speed - only 80km/h and above.

If you drop below 80 it kicks out and the revs go up. The car has more power before it kicks in at 80, so if I want to burn up a hill (on-road) at 90 it will be in " overdrive" and have not much power, if I manually shift it back to 3 then I'm in third and the revs are too high at 90. I want to be able to hold it in 4th with out it going to "overdrive".

As stated it isn't another gear or overdrive. The torque converter has a lockup in it that kicks in at 80kph. The revs drop because the torque converter is slipping. This drop shouldn't be too much from memory it is 100-200 rpm in my car. You will get better fuel economy with it locked. And the power should still be there as the drive train is locked up.

The D2 locks in both 3 & 4 gears. or so I have read and will find out soon.

[Romulus]

my understanding of the LR D1 auto is its a 4 speed box, period. 1,2,3 & D which is '4th', no additional 'overdrive' as such, am I correct with this? :confused:

[nice1guv]

Fourth gear is an overdrive as the ratio is 0.728:1.

On a V8 automatic the 3-4th shift according to the workshop manual occurs between 43-49 km/h on a light throttle 1430-1650 rpm.

Find a flat road, wind it up to 60km/h in D on a light throttle - shift back to 3, then back into D. Do it a few times - as you return to D each time, you will feel it picking up 4th gear which as stated above is an overdrive.

At 80km/h, the lock up clutch in the torque converter engages which feels like another gear as you say and the revs drop considerably. It will only lock up when in 4th (overdrive) gear.

The issue of having not enough power on hills when its locked up and over revving in 3rd is an inherent problem with these gearboxes.

That is exactly what happens.

Excellent! I understand fully. Thanks.

Now, how can I change it?

How does the clutch engage on the torque converter? It must have something that controls it coming in at exactly 80?

[B92 8NW]

my understanding of the LR D1 auto is its a 4 speed box, period. 1,2,3 & D which is '4th', no additional 'overdrive' as such, am I correct with this? :confused:

Yes. There isn't any additional overdrive unit on or anything like that, but 4th gear [0.728:1] is an overdrive by definition

[nice1guv]

my understanding of the LR D1 auto is its a 4 speed box, period. 1,2,3 & D which is '4th', no additional 'overdrive' as such, am I correct with this? :confused:

My LR D1 auto V8 has 1,2,3 plus D (or 4th) plus at 80km/h the clutch locks the torque converter (now I know that -thanks B92 8NW) and it seems like "overdrive".

It certainly doesn't pull as hard with the torque converter locked, and if you give it some curry in D it goes straight from third to 4th locked, basically jumping 4th not locked.

[B92 8NW]

That is exactly what happens.

Excellent! I understand fully. Thanks.

Now, how can I change it?

How does the clutch engage on the torque converter? It must have something that controls it coming in at exactly 80?

You can't do it easily. A trans rebuilder might be able to change it for you by increasing the spring pressure on the lock up valve, but by having it unlocked for longer, heat generation becomes an issue and the potential to wreck the autobox becomes very real.

A better solution is a mod to the valve block to enable lockup in third.

[nice1guv]

You can't do it easily. A trans rebuilder might be able to change it for you by increasing the spring pressure on the lock up valve, but by having it unlocked for longer, heat generation becomes an issue and the potential to wreck the autobox becomes very real.

A better solution is a mod to the valve block to enable lockup in third.

Won't lockup in third do the opposite of what I want? Won't it just make it weak in third and fourth then?

Hmmm....unforntunately I think it might just have to stay as it is.

Oh well, I did want a manual to begin with but couldn't find a good one over here with the other stuff I wanted. So teach me right for not waiting for the manual, although in the last year I have had the auto I still haven't seen a manual I want more.

[RonMcGr]

Won't lockup in third do the opposite of what I want? Won't it just make it weak in third and fourth then?

Hmmm....unforntunately I think it might just have to stay as it is.

Oh well, I did want a manual to begin with but couldn't find a good one over here with the other stuff I wanted. So teach me right for not waiting for the manual, although in the last year I have had the auto I still haven't seen a manual I want more.

As I said before, it is hydraulic.
That makes the ball game difficult.
It is not like a Falcon, etc, which is electric, unfortunately..

[nice1guv]

As I said before, it is hydraulic.
That makes the ball game difficult.
It is not like a Falcon, etc, which is electric, unfortunately..

Ok, forget the auto box... appears just too hard to alter the clutch lockup speed.

What about a switch to a manual box?
I would obviously have to pay someone to do this job, but is it practical?
Would I be better to start again with another disco, this time manual?
Or since the auto car I have has everything else I want, should I look at a switch to manual on this car?

[Grimace]

I understand exactly what your after.
I too wish that LR used some sort of load sensing to disengage the lock up above 80 if excessive load was endured (steep incline etc etc).

I regulary find myself wishing it would just unlock for a incline when doin 110klm just so it held the speed better. But no, if the climb is steep enough, you loose more and more speed until the auto thinks 'I might just change into third...' downshifts, revs go up, speed is gained then wham back into 4th lockup, speed drops, so again it jumps into third :mad:

Really annoys the **** out of me, specially when i know it would just hold the speed in 4th no lockup.

Something we just have to live with :mad:

[justinc]

These are the options as I see them;


1 Convert / moidify the valve body to have 3rd and 4th lockup.

2 Lighten the governor weight to change lock up (and all shift points) later

3 Install a later 4HP22EH from a D2V8 and use a compushift ECU

4 Install a 4.6 or 5.2 litre engine that will pull up any hill in OD:twisted:

As Grimace pointed out, it is a product of old school hydraulic operated autos, and is a part of D1 life....And believe me, it gets worse when you have a Tdi infront of it:(

JC

[nice1guv]

These are the options as I see them;


1 Convert / moidify the valve body to have 3rd and 4th lockup.

2 Lighten the governor weight to change lock up (and all shift points) later

3 Install a later 4HP22EH from a D2V8 and use a compushift ECU

4 Install a 4.6 or 5.2 litre engine that will pull up any hill in OD:twisted:

As Grimace pointed out, it is a product of old school hydraulic operated autos, and is a part of D1 life....And believe me, it gets worse when you have a Tdi infront of it:(

JC

I'll take the 4.6 thanks! :p

But what about a changeover to a manual?

Easy for the right person to do? or is it messing with an already mated combination? Would I be better to buy a manual and improve everything else, or switch over the auto with most other things already done?

[Pedro_The_Swift]

how much money do you want to spend?
the 5 speed should bolt straight in,
the 4.6 might need a different box as well? 4HP24?


Its a bit strange seeing Ron talk about WANTING electrics:p

[RonMcGr]

how much money do you want to spend?
the 5 speed should bolt straight in,
the 4.6 might need a different box as well? 4HP24?


Its a bit strange seeing Ron talk about WANTING electrics:p

Pedro,

Electrics in old Jaguars and most other pommie lucas fitted cars, suck :twisted:

Modern electrics are good :D
I like the clutch lockup in the Foulcan, it drops out under strain and you get extra gain. :D

[RonMcGr]

But what about a changeover to a manual?



Fine, just don't tow any thing heavy with it and expect the gearbox to last.
They are a lot weaker than the auto.
(My source? A Land Rover wrecker).

[mcrover]

Now I will try to make this as simple as possible but it is a lot more technical to get right than hard to do.

An auto box shifts on Hydraulic pressure and this is measured from the input and the output shafts on most autos including the 4HP22's as well as the 4HP22 also relies on the kickdown cable for line pressure to the clutches including the lock up clutch and I will get back to why in a sec.

To change the shift pattern you would then have to know how to change the shift pressures for each clutch range as Justinc hinted on with dropping the relief valve spring pressure to allow the trans to change into each range (ratio) earlier.

I dont understand why but if you were to want lock up on 3rd to I assume have an intermediate ratio between 3rd and 4th then you would need to save a hydraulic supply to the lock up clutch which could be done possibly with a electrically operated spool valve and major mods to the valve body or drilling relief into the valve body which would also make the change from 3rd to 4th be extremely harsh due to the extra line pressure available to the clutch.

This is where your kick down cable comes into play, it holds pressure on a spring on a control spool which supplies a balance of pressure to the kick down circuit which is controled from the throttle cable and this also controls the pressure to the clutchs to control how harsh the shift will be into each range so it is a mechanical throttle positon sensor so to speak.

It is normal for them to lock up at 80kmh and if there is a huge drop in revs then it may be that your torque converter is tired and is slipping more than it should (as mine is now) and so lock up is a huge drop in revs.

Shift pattern is 1, 2, 3 and 4th which is with the converter slipping at I think about 5% which increases torque but acts like a drop in ratio and then when the torque converter is locked up it goes to 1:1 from engine to gear train which then is at .071:1 or something like that which is an OD ratio.

The converter should only conteract the OD ratio to give approx 1:1 ratio through 4th to the output shaft.

If your not feeling the change to 4th and it doesnt drop out of lockup on load then I would say that your kickdown cable maywell be broken or not adjusted correctly.

Now there is the possability that if it's a V8 it could be a vacuum kick down (one of the V8 guys should be able to fill you and I in on that) then the servo may not be woring correctly or it may have a small leak which will cause similar symptoms.

Sorry it's a bit long and tech heavy but I think some people need to have an understanding of how their auto actually works and I hope it helps fill you in on your question.

As far as a change to manual goes, it's personal choice but I recon that doing a bit of fiddling with you trans and maybe changing the converter would end up being a fair bit cheaper and would result in a nicely sorted drive without having to worry about a clutch.

[B92 8NW]

Thanks for the write up!




<snip> and it doesnt drop out of lockup on load then I would say that your kickdown cable maywell be broken or not adjusted correctly.



I thought that the 4HP22 didn't have the capacity to unlock under load - isn't it simply in or out depending on whether you are over or under about 80kmh?

[mcrover]

Thanks for the write up!



I thought that the 4HP22 didn't have the capacity to unlock under load - isn't it simply in or out depending on whether you are over or under about 80kmh?

No probs.

No, at 140kmh mine stayed in 4th in the NT as it was under load, too much for the lockup clutch.

If everything is working properly they are great to drive but as soon as things start getting old and clearences get a bit bigger then things start getting a bit lazy and dont do things how they should.

[nice1guv]

I'm sure RonMcGr's wrecker is correct when he says the auto is stronger than the manual, but can anyone else confirm this?

Cheers mcrover, now I'm thinking maybe just a little adjustment might help things a bit.

But I'd still like to hold 4th with no lockup until 90 or 100km/h, although it seems this may not be possible with the auto box.

mcrover, if you kickdown through the cable (or vacuum) does the auto always drop to third or can it be made to kickdown to 4th no lockup? I'm pretty sure mine always kicks-down to third - haven't tried it at 140 though. :o

[stumo]

The D1 is not alone with this problem. I know my experience is with a different wagon, but it might help you decide which route to take...

I had a '94 nissan D21 terrano with exactly the same annoying shift pattern. It was a Diesel, so it made it even worse because when it kicked down, you can't build up the revs in 3rd to get back into 4th again (and then locked 4th)

I was lucky with that wagon because it was an ECU controlled AT. It was easy to mod to get it to do exactly what I wanted. So I played around with different "gears" and found that "locked 3rd" gear gave far better performance than "unlocked 4th" gear in the exact same conditions. I think something to do with 4th being an overdrive ratio like your D1.

Either way is far better than the stock setup, and I think in a V8 it would be ok just to modify it for unlocked 4th (as long as you accounted for the extra heat you will be generating in the torque converter on a long hill). but if it was easy to do (which it doesn't sound like it is) then I'd go for a locked 3rd evry time.

[81stubee]

The 4HP24E in the Range, Will happily cruise in 4th locked, and with a gentle prod on the foot will unlock, and climb a gentle hill in 4th, then if need be will kick down to third. Most of the time I find it only needs to unlock in 4th, but the cruise usually makes it kick-down to 3rd.

This of course is Electronic controlled and i can imagine it would be quite hard to do this with a purely hydraulic box, and keep it in tip top condition.

[nice1guv]

So how does this work?

I've just increased the size of my tyres from 235/70R16 to 245/75R16.
Now this increase in tyre circumference changes my speedo reading, increasing it? over before. So the old 80km/h is now roughly 84km/h?

I know the standard speedo is quite often 5km/h below actual speed, so these larger tyres have probably corrected the speedo.

BUT, why does the 4th lockup still happen at exactly 80km/h on the speedo?
Shouldn't it have moved to 84km/h with the larger tyres?

[81stubee]

The way I see it,

The overdrive is governed by the output shaft speed, and has nothing to do with the speedo. Therfore the gearbox doesn't care whether you've got 36" Simex's or 16" donut tyres, as long as the load conditions and toque converter speed to output shaft speed ratios are within tollerance.

B4 tyres:
Lockup at 76 Km/h Real speed = 80km/h Speedo Speed = Output Shaft 2000RPM guesstimate

After Tyres:
Lockup at 80km/h Real Speed = 80km/h Speedo Speed = Output Shaft 2000RPM guesstimate

Although your real speed has increased due to the tyres, the output of the gearbox is still turning at the same rate, just the tyres travel further with each turn.

Stu