Torque Convertor lock up issue perhaps?

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revmarkp said:
delayed reply as I wanted to get some miles done before reporting back.

Put in the Lucas Fix - btw it takes a while - very thick treacley stuff!

Done 700-800 miles now (mostly motoroway) and.... It's getting worse :-(

Resigning myself to a new gearbox, but even that isn't proving straightforward. Called an auto tranny specialist in Barnsley, who is advising I check the Airflow Meter, Turbo Waste Gate and EGR Valve, as they might cause my symptons - don't think he fancied the job really...

Ashcroft Transmissions similarly non committal about my diagnosis.

Just to reiterate my symptoms were/are:

Initially, gearbox shifting in and out of torque lockup (at least that was my guess), anyway the revs constantly jumping from 2550 to 2850 all the time, back and forth - when cruising on motorway at 70mph.

now more recently (perhaps since changing ATF and filter?) reluctance to shift into correct gear, high revving producing no change of gear. down-shifting too early. changes gear but then immediately changes back etc etc. Erratic or reluctant shifting in a nutshell.

Faultmate says no gearbox ECU faults; Speed sensor o/p via faultmate reads normal.

From further reading about how these boxes work it might be the governor???

Anyone recommend Rangy/P38 garage in Notts/Derby/S Yorks area to diagnose/fix?
Click to expand...

There is no governor on the electronically controlled version of the ZF4HP22/24.
 
My mechanic is Warren @ WGB Autos off London Road in Sheffield. Specialises in Land Rovers (especially P38's). He's very thorough & wont rip you off.
 
revmarkp said:
delayed reply as I wanted to get some miles done before reporting back.

Put in the Lucas Fix - btw it takes a while - very thick treacley stuff!

Done 700-800 miles now (mostly motoroway) and.... It's getting worse :-(

Resigning myself to a new gearbox, but even that isn't proving straightforward. Called an auto tranny specialist in Barnsley, who is advising I check the Airflow Meter, Turbo Waste Gate and EGR Valve, as they might cause my symptons - don't think he fancied the job really...

Ashcroft Transmissions similarly non committal about my diagnosis.

Just to reiterate my symptoms were/are:

Initially, gearbox shifting in and out of torque lockup (at least that was my guess), anyway the revs constantly jumping from 2550 to 2850 all the time, back and forth - when cruising on motorway at 70mph.

now more recently (perhaps since changing ATF and filter?) reluctance to shift into correct gear, high revving producing no change of gear. down-shifting too early. changes gear but then immediately changes back etc etc. Erratic or reluctant shifting in a nutshell.

Faultmate says no gearbox ECU faults; Speed sensor o/p via faultmate reads normal.

From further reading about how these boxes work it might be the governor???

Anyone recommend Rangy/P38 garage in Notts/Derby/S Yorks area to diagnose/fix?
Click to expand...

There is no governor in the P38 box. It is a sticky valve block. Or lack of oil pressure. Can't be a lot else if there are no electronic faults.
 
My mechanic is Warren @ WGB Autos off London Road in Sheffield. Specialises in Landys & P38's in particular. He wont rip you off either. I'll be taking mine into him as i get the feeling my box isn't the same recently either, seems to be staying in 4th at low speed now & then & reluctant to pick up unless booted, only intermittent but better to get it looked at.
 
i would think you definitely had a box problem ,you dont have a mechanical govenor ,but oil change can effect a worn box by the detergent effect on valve block and oneway clutches, especially if youy have a failing clutch pack ,try bradley on 01283521414
 
Last edited:
It may not be relevant, but I know Datatek and others always bang out about sensitivity of these beasts to voltage.

Your video shows only 13.8/13.9 volts at around 2,600rpm - shouldn't it be around 14.4 volts?

Pete
 
Pete The Biker said:
It may not be relevant, but I know Datatek and others always bang out about sensitivity of these beasts to voltage.

Your video shows only 13.8/13.9 volts at around 2,600rpm - shouldn't it be around 14.4 volts?

Pete
Click to expand...

Unless you have a 4.6 fitted with an 150amp alternator you will NEVER see 14.4 volts on a P38. The maximum you will ever see is 14.2 and that would be with a alternator in tip top condition. 13.8-13.9 is pretty decent for one with a bit of use in it. Charging rate is variable not constant.
 
wammers said:
Unless you have a 4.6 fitted with an 150amp alternator you will NEVER see 14.4 volts on a P38. The maximum you will ever see is 14.2 and that would be with a alternator in tip top condition. 13.8-13.9 is pretty decent for one with a bit of use in it. Charging rate is variable not constant.
Click to expand...

I stand corrected! :)

Pete
 
wammers said:
Unless you have a 4.6 fitted with an 150amp alternator you will NEVER see 14.4 volts on a P38. The maximum you will ever see is 14.2 and that would be with a alternator in tip top condition. 13.8-13.9 is pretty decent for one with a bit of use in it. Charging rate is variable not constant.
Click to expand...
Sorry, I have to disagree again. If the battery is good, the alternator fitted to the P38 should show 14.2 volts withing a short time of starting when held at 2K rpm. Less could indicate a cell failing in the battery, a duff regulator in the alternator or other problems like bad connections, worn brushes, duff diode pack etc. It could also be that at some time the alternator has been changed for one with a lower output.
13.8/13.9 volts is not enough to fully charge a modern low maintenance lead calcium battery.
Regulated output voltage does not change significantly with age unless there is a fault. If the regulator is set to 14.2 volts, the alternator is fault free and the battery is OK, then 14.2 volts is what you should see:)
 
Datatek said:
Sorry, I have to disagree again. If the battery is good, the alternator fitted to the P38 should show 14.2 volts withing a short time of starting when held at 2K rpm. Less could indicate a cell failing in the battery, a duff regulator in the alternator or other problems like bad connections, worn brushes, duff diode pack etc. It could also be that at some time the alternator has been changed for one with a lower output.
13.8/13.9 volts is not enough to fully charge a modern low maintenance lead calcium battery.
Regulated output voltage does not change significantly with age unless there is a fault. If the regulator is set to 14.2 volts, the alternator is fault free and the battery is OK, then 14.2 volts is what you should see:)
Click to expand...

The charging rate depends on the battery state and demand we have been through this before. The regulator turns it up and down as required. As i understand it calcium batteries need at least 14.4 volts to promote the chemical change required to charge them. So the moral is, unless you change the regulator on you P38 don't fit a calcium battery it will never get fully charged. :):)
 
Thanks for the input again recently - appreciated.

I'm pricing up various people re: recon autobox - will report back later on that...

Is my DSE worth spending £1500 on?!!! lol (haven't found a cheaper way to tow 3.5 ton yet!)

As a side issue I've always fancied front fog lights on the DSE, but the tranny cooler prevents them on the diesel auto's of course; As i contemplate a new gearbox I notice my tranny cooler is leaking slightly. Some folks fit an alternative cooler in front of the lower part of the radiator, then you can fit the fog lights

Any perceived thoughts on the wisdom of this? Presumably main issue is possibility restricting airflow to (& introducing more heat in front of) water rad.
 
wammers said:
The charging rate depends on the battery state and demand we have been through this before. The regulator turns it up and down as required. As i understand it calcium batteries need at least 14.4 volts to promote the chemical change required to charge them. So the moral is, unless you change the regulator on you P38 don't fit a calcium battery it will never get fully charged. :):)
Click to expand...

The regulator is fixed, it does not, indeed cannot, turn the voltage up and down, look at it as a voltage limiter and it makes more sense, the voltage can go below the fixed point if the demand is greater than the alternators ability to supply.
All modern batteries that are maintenance free are lead calcium, unless you fit a gel battery. The required charging voltage is in the range of 14.2 to 14.8 volts.
 
revmarkp said:
Thanks for the input again recently - appreciated.

I'm pricing up various people re: recon autobox - will report back later on that...

Is my DSE worth spending £1500 on?!!! lol (haven't found a cheaper way to tow 3.5 ton yet!)

As a side issue I've always fancied front fog lights on the DSE, but the tranny cooler prevents them on the diesel auto's of course; As i contemplate a new gearbox I notice my tranny cooler is leaking slightly. Some folks fit an alternative cooler in front of the lower part of the radiator, then you can fit the fog lights

Any perceived thoughts on the wisdom of this? Presumably main issue is possibility restricting airflow to (& introducing more heat in front of) water rad.
Click to expand...

As i keep saying, but nobody takes notice, you can fit the fogs if you modify the bumper.
 
Datatek said:
The regulator is fixed, it does not, indeed cannot, turn the voltage up and down, look at it as a voltage limiter and it makes more sense, the voltage can go below the fixed point if the demand is greater than the alternators ability to supply.
All modern batteries that are maintenance free are lead calcium, unless you fit a gel battery. The required charging voltage is in the range of 14.2 to 14.8 volts.
Click to expand...

My battery is not a calcium battery. That was new last year. :)
 
Datatek said:
Yep. Not seen any like that for a while except on tractors. If you have 14.2 volts you could cook it on a long run:eek:
Click to expand...

No because the regulator senses the battery voltage and adjusts the current in the field coils turning the alternator output up or down. A full charged battery will not receive a charge from the alternator but one that falls below say 12.5 volts will. 14.2 volts set point of the regulator is the maximum voltage that will be allowed to be put through the field coils and would give maximum output. This will vary, controlled by the regulator between 13.5 and 14.2 depending on the batteries state of charge and alternator charge rate needed. If the regulator had a set point above 14.2 which is regarded as the maximum charge rate for lead acid batteries, then yes it would boil the electrolite off in time.
 
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