Are all 4HP-22 gearbox’s all the same?

[reggie]

I need a refresher course on Land Rover gearboxes

I should know all this stuff but I’m slightly unsure. Is the 4HP-22 gearbox the same on all models like RRC, P38, Disco 1, D2 apart from Bell housings and torque converters?

Say for instance I need a gearbox for my RRC (which I do) would a P38 gearbox fit in? I have a 4HP-22 in the garage but not sure if it’s off a D2 or P38. Would I just need to fit the Borg Warner viscous transfer box and good to go? What torque converter for example as it has one but not a RRC one?  

Edited January 27, 2018 by reggie

[steve200TDi]

I've been doing a bit of research lately regarding 4HP-22's. The 3 digit serial number stamped in the box on the little plate on the side seems to refer to a particular model year and vehicle. I cannot find anything else online regarding this apart from this little snippit from this website:

http://roverlanders.bc.ca/roverforum/viewtopic.php?f=5&t=8590

Someone also said that each variant is slightly different, but I have no info to back this up!

I also know that you can get different torque converters and this can change how the box reacts, but I need more info to understand the effects!

On the Ashcrofts website for the torque converters they say it is very important to install the converter properly and getting the right depth etc.

http://www.ashcroft-transmissions.co.uk/miscellaneous/torque-converters/torque-converter.html

Hope this helps.

(I'm trying to diagnose a kick down fault (here:

and so I might be swapping out my gearbox too, but I need to find one I know works before going through the effort of fitting one to find it doesn;t work!) )

[Shackleton]

The D2 is different from the RRC in that it's electrically controlled at least. I think it's also improved In some mechanical way. It's model designation is 4HP22EH accordingly. Don't know any more other than the P38 one isn't a 4HP22 it's a 4HP24.

sorry I have that muddled slightly - p38 diesels use the 22 and the v8's use the 24 I think

Edited January 28, 2018 by Shackleton

[reggie]

I’ve broke a good few range rovers over the years and from my limited knowledge I’m pretty sure that it’s only the 4.6 P38 that uses the 4HP-24 gearbox. The diesel P38 and 4.0 use the 4HP-22 as does the D2 4.0 V8 and 3.9 RRC and D1. Not sure on the RRC 3.5 V8 though as never had or broke one.

I think that there are 3 different size torque converters for the P38. The 4.6 has the biggest one, the 4.0 has a smaller one and the diesel the smallest. Not sure if they have different bell housings though.

The RRC a D1 V8 use the same bell housing and torque converter I believe, just transfer box is different with the RRC using the Borg Warner viscous unit. 

Where I start to get unsure is the electronic control you talk about on the D2 George, is this only on the D2 I wonder? Is this not compatable with a RRC then with XYZ switch removed? Or could a 4.0 P38 4HP-22 with the right torque converter and XYZ switch removed be used in a RRC or is the D2 one different to the P38? 

This is the one I have lying around and I think it’s out of a D2, is that plug in the body what controls it electronically? Pretty sure from memory that the P38 doesn’t have that plug. If so then I’m guessing a D2 one can’t be used in anything other than a D2.

Edited January 28, 2018 by reggie

[rick]

On 28/01/2018 at 6:51 PM, steve200TDi said:

I also know that you can get different torque converters and this can change how the box reacts, but I need more info to understand the effects!

On the Ashcrofts website for the torque converters they say it is very important to install the converter properly and getting the right depth etc.

 

Ashcroft's can do an upgraded (larger) low stall converter and a stronger drive plate for the TD5 if it's chipped/modified.

 

This suits the torque characteristics of the modded engine better as well as being a lot stronger.

Dave has stated in the past that the stock TD5 converter is marginal for a stock engine at the best of times.

If $$ allow they can also do some 4HP24 bits internally to allow the 'box to better handle the power/torque of  modified TD5

[BogMonster]

Pretty sure the shift points differ between V8 and diesel for example, different settings in the valve block inside. Talk to Dave Ashcroft, what he doesn't know about this sort of stuff I could write on the back of my ear.