I have done a parts search on Microcat and the diesel auto uses different propshafts than 4.0/4.6 autos. The props may be different lengths because of the differences in gearbox length between the HP22 and HP24.

Also the diesel auto has a coupling adapter FTC5067 on the rear propshaft.
I don't think this is fitted to the 4.0/4.6.
 
i had noticed a different coupling between the auto and manual diesels but i naturally assumed that because there was a difference of 4 years between manufacture between the vehicles i thought it was change in design on all vehicles i must look into the possibility of the difference length between petrol and diesel shafts.
 
dave4x4 said:
I have done a parts search on Microcat and the diesel auto uses different propshafts than 4.0/4.6 autos. The props may be different lengths because of the differences in gearbox length between the HP22 and HP24.

Also the diesel auto has a coupling adapter FTC5067 on the rear propshaft.
I don't think this is fitted to the 4.0/4.6.
Click to expand...

I believe the different lengths are due to the different coupling and auto/manual?
 
I have got the story on the gearboxes:

There are 3 gearboxes for the p38. The HP22 and two HP24 variations - early and late.
The late type is identified by 065 as the last number on the name plate. With the diesel bellhousing this box works out the same length overall as the diesel HP22. It is a direct swap.

The earlier HP24 (sorry I don't have any numbers for these) is actually 15mm longer. If you fit a HP22 diesel tailend to this box it works out the same length - not necessary if you get an 065 box. Otherwise I am told you can alter the holes in the gearbox mount and the propshafts should accommodate the slight difference in lengths - not confirmed however !

Also only the diesel torque converter will fit into the diesel bellhousing. The 4.0 and 4.6 are too big.
As mentioned the diesel torque converter can however be modified internally by Ashcrofts to have a lower stall speed for a chipped engine. It won't slip as much and will change up earlier.

Full story in 2 weeks - Ashcrofts are fitting my HP24 for me.

Dave
 
dave4x4 said:
I have got the story on the gearboxes:

There are 3 gearboxes for the p38. The HP22 and two HP24 variations - early and late.
The late type is identified by 065 as the last number on the name plate. With the diesel bellhousing this box works out the same length overall as the diesel HP22. It is a direct swap.

The earlier HP24 (sorry I don't have any numbers for these) is actually 15mm longer. If you fit a HP22 diesel tailend to this box it works out the same length - not necessary if you get an 065 box. Otherwise I am told you can alter the holes in the gearbox mount and the propshafts should accommodate the slight difference in lengths - not confirmed however !

Also only the diesel torque converter will fit into the diesel bellhousing. The 4.0 and 4.6 are too big.
As mentioned the diesel torque converter can however be modified internally by Ashcrofts to have a lower stall speed for a chipped engine. It won't slip as much and will change up earlier.

Full story in 2 weeks - Ashcrofts are fitting my HP24 for me.

Dave
Click to expand...

Do you mean lock up earlier, don't know how it would do that as the lockup clutch is not controlled by the converter itself?
 
I had the idea that the lockup was was at a given speed, but since the repro and bigger intercooler mine started to lockup at 45mph when it used to be at 50mph and it started to change gears earlier.
 
JotaPê;2176920 said:
I had the idea that the lockup was was at a given speed, but since the repro and bigger intercooler mine started to lockup at 45mph when it used to be at 50mph and it started to change gears earlier.
Click to expand...

Mine locks up at 45 + on moderate throttle always has done, hard throttle a little higher around 50-52 MPH. ECU locks torque convertor, it depends on throttle position and engine speed. Cannot see how an intercooler change can overly affect the operation of the gearbox.
 
i sent ashcroft an email yesterday asking if a converter was available for a p38 diesel that would lock up at a lower speed/rev. the answer i got was that the converter has nothing to do with it its the gearbox that locks up controlled by the gearbox ecu
 
wammers said:
Do you mean lock up earlier, don't know how it would do that as the lockup clutch is not controlled by the converter itself?
Click to expand...

He means the slip is reduced, ie the convertor will will drive at lower revs and rotor and stator will approach the same rotational speed under higher loads:)
 
dave4x4 said:
I have got the story on the gearboxes:

There are 3 gearboxes for the p38. The HP22 and two HP24 variations - early and late.
The late type is identified by 065 as the last number on the name plate. With the diesel bellhousing this box works out the same length overall as the diesel HP22. It is a direct swap.

The earlier HP24 (sorry I don't have any numbers for these) is actually 15mm longer. If you fit a HP22 diesel tailend to this box it works out the same length - not necessary if you get an 065 box. Otherwise I am told you can alter the holes in the gearbox mount and the propshafts should accommodate the slight difference in lengths - not confirmed however !

Also only the diesel torque converter will fit into the diesel bellhousing. The 4.0 and 4.6 are too big.
As mentioned the diesel torque converter can however be modified internally by Ashcrofts to have a lower stall speed for a chipped engine. It won't slip as much and will change up earlier.

Full story in 2 weeks - Ashcrofts are fitting my HP24 for me.

Dave
Click to expand...

That's pretty much what I have been saying for a long time now, although I did not know about the 2 versions of the HP24. I'd be suspicious of the later shorter one as that sound like an uprated 22 to me, no room for the bigger clutches.:)
 
Let me just clarify a few points with the gearboxes as best I can - and don't shoot the messenger, I got all this from Dave Ashcroft. I have just spent a day taking my gearbox down there and picking his brains.

Firstly I must say the setup at Ashcrofts is pretty impressive. I had a tour around the workshops and there were about 12 to 15 employees rebuilding gearboxes on 2 floors, a big operation. All they do is L/R boxes so are the experts in the field. Inventory was huge and they do there own lockers now. Dave was very helpful.

Regarding the torque converter, the uprated one they do for the diesel takes up the drive earlier and has less slip resulting in less heat generation. The engine runs at lower revs if you have got a nice torquey engine. It transfers the drive better so you do not rev past it. It doesn't change the lower gear shift points which is done by the ECU.

He made the point that most of the p38 and Disco TD5 gearboxes warranty failures that Ashcrofts see are due to the gearbox being "cooked". A typical scenario would be towing a heavy caravan up through the Alps on a hot day, 40 deg C, going 50 mph and the torque converter hasn't locked up. It is slipping all the time generating heat in the gearbox. This is like deja vue for me. We spent some time looking at my DSE gearbox cooling. I have the original cooler under the wing which has the later fan fitted - so L/R obviously knew there was a problem. He recommended a second cooler on the other side - which I am not going to do! but what I am doing is getting a boss welded onto the gearbox sump so I can fit a temperature gauge.

Regarding the gearboxes. Picture the gearbox in 4 sections. The bellhousing, the oil pump housing, the main gearbox housing containing the cogs and clutches and a tailend housing. It is the oil pump housing which is different in length for early and late HP24s. I was told the main case is the same length for all HP22 and HP24 boxes. The difference in length is accommodated for by using the appropriate tailend, so an early HP24 box with a diesel bellhousing and a diesel tailend will fit, or a later 065 box with just the diesel bellhousing.

All the later HP24 065 boxes have the stronger HP24 clutch packs and internals as standard. Mine was made for a 4.6 Thor engine.

Ashcrofts also offer another option of having a HP22 box fitted with the HP24 internals. Stage 1, I think is having the C1/C2 one way clutch and planetary gearset upgraded and stage2 is the A clutch as well.

I am also staying with the diesel gearbox ECU. They do offer a Compushift option which is very expensive. Anyone hacked into the ECU ? I know a couple of people who would be very interested.

Dave
 
Last edited:
dave4x4 said:
Let me just clarify a few points with the gearboxes as best I can - and don't shoot the messenger, I got all this from Dave Ashcroft. I have just spent a day taking my gearbox down there and picking his brains.

Firstly I must say the setup at Ashcrofts is pretty impressive. I had a tour around the workshops and there were about 12 to 15 employees rebuilding gearboxes on 2 floors, a big operation. All they do is L/R boxes so are the experts in the field. Inventory was huge and they do there own lockers now. Dave was very helpful.

Regarding the torque converter, the uprated one they do for the diesel takes up the drive earlier and has less slip resulting in less heat generation. The engine runs at lower revs if you have got a nice torquey engine. It transfers the drive better so you do not rev past it. It doesn't change the lower gear shift points which is done by the ECU.

He made the point that most of the p38 and Disco TD5 gearboxes warranty failures that Ashcrofts see are due to the gearbox being "cooked". A typical scenario would be towing a heavy caravan up through the Alps on a hot day, 40 deg C, going 50 mph and the torque converter hasn't locked up. It is slipping all the time generating heat in the gearbox. This is like deja vue for me. We spent some time looking at my DSE gearbox cooling. I have the original cooler under the wing which has the later fan fitted - so L/R obviously knew there was a problem. He recommended a second cooler on the other side - which I am not going to do! but what I am doing is getting a boss welded onto the gearbox sump so I can fit a temperature gauge.

Regarding the gearboxes. Picture the gearbox in 4 sections. The bellhousing, the oil pump housing, the main gearbox housing containing the cogs and clutches and a tailend housing. It is the oil pump housing which is different in length for early and late HP24s. I was told the main case is the same length for all HP22 and HP24 boxes. The difference in length is accommodated for by using the appropriate tailend, so an early HP24 box with a diesel bellhousing and a diesel tailend will fit, or a later 065 box with just the diesel bellhousing.

All the later HP24 065 boxes have the stronger HP24 clutch packs and internals as standard. Mine was made for a 4.6 Thor engine.

Ashcrofts also offer another option of having a HP22 box fitted with the HP24 internals. Stage 1, I think is having the C1/C2 one way clutch and planetary gearset upgraded and stage2 is the A clutch as well.

I am also staying with the diesel gearbox ECU. They do offer a Compushift option which is very expensive. Anyone hacked into the ECU ? I know a couple of people who would be very interested.

Dave
Click to expand...

Very interested to hear the outcome of this and the cost:D
I've been looking at trying this on a DIY basis but am unwilling to risk the cost if it's not going to work.
Also I have yet to pluck up the courage to try dropping the lump as it's so heavy:eek:
My info from the ZF factory was the the HP24 box itself was longer than the HP22?
 
Datatek:
As I said Ashcrofts are doing the whole job. I was going to change the box myself but I chickened out. I don't have all the gear - although I have taken out a classic box by myself. It came out from inside through the door.
I think if you take the transfer box off and do it in two stages it would be easier. They are still bloody heavy. Lifting the gearbox into the back of the car I would guess it is 150 - 200 lbs (no transfer box). You really need a four post lift and a gearbox support or find yourself a couple of strong French boys ducky.
Your info from ZF must be referring to the earlier box. It is 15mm longer overall because of the pump housing. What is the date on the document? The later 065 box is, so I am told the same.

qwertz:
No, I didn't have a discussion with Ashcrofts about that, but I think we all know it feels like changing up into a fifth gear. It is overheating of the gearbox that causes the damage and heat is caused by slippage. I think it is only a problem if the engine has been chipped and is putting out a lot more power and torque.
Although there is a temperature alarm already on the cooler a temperature gauge was strongly recommended. I think I recall 105 deg C as a max.
 
dave4x4 said:
Datatek:
As I said Ashcrofts are doing the whole job. I was going to change the box myself but I chickened out. I don't have all the gear - although I have taken out a classic box by myself. It came out from inside through the door.
I think if you take the transfer box off and do it in two stages it would be easier. They are still bloody heavy. Lifting the gearbox into the back of the car I would guess it is 150 - 200 lbs (no transfer box). You really need a four post lift and a gearbox support or find yourself a couple of strong French boys ducky.
Your info from ZF must be referring to the earlier box. It is 15mm longer overall because of the pump housing. What is the date on the document? The later 065 box is, so I am told the same.

qwertz:
No, I didn't have a discussion with Ashcrofts about that, but I think we all know it feels like changing up into a fifth gear. It is overheating of the gearbox that causes the damage and heat is caused by slippage. I think it is only a problem if the engine has been chipped and is putting out a lot more power and torque.
Although there is a temperature alarm already on the cooler a temperature gauge was strongly recommended. I think I recall 105 deg C as a max.
Click to expand...


The info I had from the man at ZF (on the phone) intimated that there was only one basic HP24 varient and it was longer then the 22. Looking at the the clutch packs, I'm not sure how they would get the bigger HP24 clutches into the HP22 length box. I'm no expert, only repeating what I was told:confused:
 
very interesting reading im thinking that the solution to making the diesel less sluggish is to fit the uprated converter and get the autobox ecu remapped
Dave 4x4 . to answer your question i have heard that somebody here in ireland can operate on your gearbox ecu i will try to make contact with him next week to find out what he does and what it costs
 
Yes, it says with the HP24 front end fitted it is 15mm longer. Presumably this means the pump housing. However I was told that with the shorter diesel tailend fitted as well it works out the same length.
Will clarify when I am down there.
 
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