Auto box differences?

[robhybrid]

what is the difference between:-

V8 4 speed auto box?

300 tdi auto box?

P38 auto box?

I have seen a P38 Auto box for sale (done90k) and wondered if I could use it where a RR4 speed auto box had been intended?

I would be putting a 2.8 Izusu in front of it and a lt230 transfer box on the back.

When did the boxes go fancy with electrical gadgets?

Is there any advantage to using one of these and what would be invoved?

I guess I am looking for replies from? lara,will warn,Western? anyone? gearboxdave?

[Turbocharger]

I know the valving is different on a 300Tdi box, although considered opinion is that a Tdi will work with a V8 box, changing in slightly different places, that's all. Don't know if that'd suit an Isuzu lump though.

[will_warne]

Rob, I'll pop something up later today or tomorrow. There are quite a few differances but anythings possible. P38 box has some useful features, though.

[robhybrid]

pm sent, egarly awaiting reply

[will_warne]

OK, I'll try and put in everything that I know.

The box fitted to p38s is an electronic version of the ZF4 box. Instead of using a hydrolic valve body to control the shifts it uses an electronic one controlled via an ECU. On top of this the torque convertor has a lock up clutch controled via a solinoid. Lara has added a switch in to allow him to lock up the clutch on his to give him better engine braking. Both of these mean you can have a 'Sport' mode that locks up the torque convertor and means the vehicle drives more like a manual. Annother differance (I assume) is the rear end of the box as I can't imagine the bolt patterns for the BW transfer box are the same as those for either the LT230.

On top of this there are 3 differant flavours of p38 box: the one fitted to the 2.5D (I guess differant bellhousing, TC and ECU) which is HP22 spec (so simerlar oil pump and clutch packs to those on a 3.9 RRC box). Then there's the one fitted to the 4.0 which is a V8 version of the one fitted to the 2.5D and is HP22 spec. Finally, there's the one fitted to the 4.6 which is an HP24 spec box. This is where the oil pump, clutch pack and, IIRC, quite a lot of the internals in my box come from. However, the person to ask about exactly what's in there is either Ian or Dave Ashcroft.

The next complication is the DII boxes. These are also electronic boxes and I think they're very simerlar to the ones in p38s. However, they have a differant shifter setup so I'm guessing at least the ECUs are differant. Lara might be able to throw more light on this.

Fitting wise, its a little harder than using a hydrolic valve body box as you've got an ECU to waterproof and, as far as I understand, you've got to make the engine talk to to the ECU on the gearbox. Its far from impossible, though, as quite a lot of people have done the conversion to Tdis/TGVs along with other mechanically controlled diesel engines. My advice is have a word with M&D, they've done quite a few kits now for p38s. The other thing that might cause problems is transfer boxes. You can't use a standard p38 t.box as the output flanges are on the wrong sides. That means you need to fit an LT230, which means you have to change the casing on the back of the box. You then run into problems with the shifter. I guess the ECU will throw a wobbley as it'll be difficult to link up an LT230 to work through the H gate (which I think you'll have to keep).

In the end, although you gain a 'Sport' mode and the ability to lock the TC, I'd use a hydrolic box. The Devon 4x4 bobtail uses a DII based box which I think is easier to work with as the gearbox is stand alone. I looked into fitting an electonic box but decided against it on the grounds of cost and complexity. Also an underdrive will sort the engine breaking problem and my truck isn't really a road vehicle (making sport mode fairly useless). The other thing is that the electronic box torque convertor seems to be weaker. Lara has had problems with them once you put big torque through them.

I'm sure I'll think of something else to add but that should be most of it....

[ashtrans]

Hi Rob,

for starters please advise what manual box you have installed now, preferably the serial number, stamped on the oval flat below the oil filler level plug,

also,

Please advise the last 3 digits of the second number down on the ID plate on the LHS of the autobox,

I will warn you now, I don't think this is going to be easy,

[white90]

Rob fit a decent engine rather than that stinky old one

a nice 300TDI is what you need.

and to stop this charge towards Auto..

A nice Under drive is what you need

[dollythelw]

decent engine?? Isuzu vs 300Tdi?

sounds likes a wager to me.....................

Edited January 1, 2006 by dollythelw

[will_warne]

Urm, I think the 300's beat for performance but I'll take you on with a tuned TGV I've seen a few Isuzu engined Landys in action, some have been convincing, some less so. I think a lot of its personal preferance.

Tony, auto works very well. Its not perfect yet (more power needed as is an underdrive) but once its done you need to have a go. I've already convinced a few people who though I'd gone soft

Rob, what swap are you doing at the moment? 2.8 Isuzu behind the HP22 out of the V8 disco (200tdi type) that was outside your parents place? If so, that shouldn't be too hard; plenty of people have done simerlar things.

[Bush65]

Although I don't have personal experience with the Isuzu 2.8, they are pretty reasonable by all accounts. I do know that Isuzu build some great diesel engines. In the 1st post at the top you said you would be using a 2.8 Isuzu, so I would stick with that decision.

I recently replaced the v8 in my rangie with a 300TDi and R380. At the time I didn't want to fiddle with gearbox conversions and I don't know of anyone here making 2.8 Isuzu to R380 kits here in Aus.

I regret that I did not go with a 2.8 Isuzu - in light of all the other changes I have made the gearbox adaptor would have only added a little more work.

I have an Isuzu 4BD1-T in my other truck and this is a great engine (better than a tuned TGV IMHO ). It is a problem getting a nice, strong gearbox for a tuned 4BD1-T in a Rover. There is another problem with auto boxes behind these as they have too much torque from idle - they can drive through the brakes in low range.

Regarding the ZF HP22/24, does anyone over there, do a sprag clutch conversion for them, to overcome the engine braking problem. There is a company here that does and it has been reported to work well. The sprag clutch is free when the engine is driving, and locks the convertor when the torque direction is reversed (ie when engine braking).

[will_warne]

Bush, not heard about anyone doing that conversion but it sounds interesting. I'm not sure how it'd 'lock' the TC, though. Engine breaking isn't amazing on mine but it isn't terrible. I guess its about the same as using second when I had a manual.

[robhybrid]

Hi Rob,

for starters please advise what manual box you have installed now, preferably the serial number, stamped on the oval flat below the oil filler level plug,

also,

Please advise the last 3 digits of the second number down on the ID plate on the LHS of the autobox,

I will warn you now, I don't think this is going to be easy,

The old box was a short bell housing lt77(I am not sure the serial numbers on ythat are relevant or correct as I made the box myself out of several parts in the past)

The auto box I intend on using in the short term is a hp22 last 3 digits 212 I think.(oops looked at ashcroft websit and I think I have read serial no by mistake will try again tomorrow)

I have my Izusu engine fastened to the box with a milner and pearson conversion plate and a Conversion and pressision modified flywheel/drive hub and drive plate.

The box is currently bolted into my truck using the 200tdi transfer box mounting and a modified Discovery auto box mounting (plate welded to it and the mounting rubber moved 50mm forward)

I have cut off my engine mountings and intend on re welding them to my chassis some 5" further forward.

Please have a look at my other post (question for Dave) and I shall aim to give you a ring mid day(tue)

Edited January 2, 2006 by robhybrid

[robhybrid]

had a look at my auto box this eve and the last three digits on the row of nos in the second row are:-

742

Hope this makes sense

[ashtrans]

The old box was a short bell housing lt77(I am not sure the serial numbers on ythat are relevant or correct as I made the box myself out of several parts in the past)

The auto box I intend on using in the short term is a hp22 last 3 digits 212 I think.(oops looked at ashcroft websit and I think I have read serial no by mistake will try again tomorrow)

I have my Izusu engine fastened to the box with a milner and pearson conversion plate and a Conversion and pressision modified flywheel/drive hub and drive plate.

The box is currently bolted into my truck using the 200tdi transfer box mounting and a modified Discovery auto box mounting (plate welded to it and the mounting rubber moved 50mm forward)

I have cut off my engine mountings and intend on re welding them to my chassis some 5" further forward.

Please have a look at my other post (question for Dave) and I shall aim to give you a ring mid day(tue)

Hi,

OK, LT 77 4 Cyl coming out, V8 ZF going in,

2 tricky bits are :

1) bellhousing bolt pattern, not only do you need to get an adapter ring for the block to get to the V8 bolt pattern but the engine to autobox alignment must be spot on, this is a thread in itself but the bottom line is the block to backplate and backplate to bellhousing dowels must be correct so as to ensure no more that 0.005" total run out. if you have more than this you will suffer from flexplate failures like clockwork.

2) starter ring / boss / flexplate assy, also must be right so as to ensure correct torque converter positioning, some careful measuring required here,

[dollythelw]

I can vouch for the CPE Isuzu/V8 ZF adaptor giving no concerns about flexplate life

[SimonPearson]

This one's a real toughie Rob... as you know, I have an Isuzu 2.8 in my 90 and I've had more than my fair share of Tdi's before. Whoever says they think a Tdi is better is simply nuts - they either haven't owned an Isuzu 2.8 or simply don't know what they're talking about.

That said, I was in the same dilemma as you - I wanted an Auto. In fact, I care more about having an auto than I do about what engine is in front of it!

I actually had a 300Tdi autobox sitting spare as well.. but having looked into the aggravation (and associated cost) of fitting it all together it was simply easier to stick with the tried and tested V8 / Auto combo.

On the other hand - have you thought about getting an Isuzu Auto to go with the engine? My wife's 3.1Tdi Auto Trooper goes like stink and drives great.