cheongthong said:

I mean will it work for the 4hp22

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You have to use the diesel torque convertor on the HP24 same as the HP22 as the petrol ones will not fit the diesel bell housing, but it works fine, it's been done.

I still haven't checked my solenoid resistances yet but hope to tomorrow. I will make a few enquiries with the local autobox expert also.
The 4hp22 auto is fitted to a heap of vehicles and i imagine would interchange as long as you use the correct bell housing and torque converter. I guess the internals of all 4hp22 transmissions would be the same, it would just be the different stall ratio of the torque converters that determine the required load to get the vehicle moving. Ie the torque from a 4.0 v8 would be far greater than a 2.5 diesel so the torque converter would need to have different specs. If you used a v8 petrol torque converter in a diesel application then i'm guessing that the diesel would be even more sluggish at pulling away than it is normally, HOW BAD WOULD THAT BE!!!

spadgr said:

I still haven't checked my solenoid resistances yet but hope to tomorrow. I will make a few enquiries with the local autobox expert also.
The 4hp22 auto is fitted to a heap of vehicles and i imagine would interchange as long as you use the correct bell housing and torque converter. I guess the internals of all 4hp22 transmissions would be the same, it would just be the different stall ratio of the torque converters that determine the required load to get the vehicle moving. Ie the torque from a 4.0 v8 would be far greater than a 2.5 diesel so the torque converter would need to have different specs. If you used a v8 petrol torque converter in a diesel application then i'm guessing that the diesel would be even more sluggish at pulling away than it is normally, HOW BAD WOULD THAT BE!!!

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Not all 4HP22's are physically the same, many went into 2wd vehicles and have different tail shafts, housings etc. It's also possible that the gear ratios may be different.
It's not just engine torque that determines the torque convertor spec, it's also vehicle weight and available space. The diesel would be better with the 4.6 torque convertor, less slip, but it will not fit in the bell housing. Ashcroft transmissions do an uprated torque convertor for the diesel.

I mean the box code in depth in mm , , do the 4hp24 has the same code as the 4hp22 depth in mm ? And how do they measure this depth in MM of the torque coverter in the as ?

I bought a 1999 4.0 range rover with this problem you would be driving along fine and it would decide to change down gear and back up for no reason the only thing I could find wrong was the oil was slightly to high on the dipstick dropped the oil to correct level and it hasn't been a problem since and I have had it 2 years now.

found this, maybe this will help if you need to coverter the 4hp22 to 4hp24


follow this link

Torque Converter Installation Instructions

trucker2369 said:

I bought a 1999 4.0 range rover with this problem you would be driving along fine and it would decide to change down gear and back up for no reason the only thing I could find wrong was the oil was slightly to high on the dipstick dropped the oil to correct level and it hasn't been a problem since and I have had it 2 years now.

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I'd second this - had similar with an XJ6. Too much oil causes some odd behavior on some boxes. I'd also change the oil before I resorted to swapping boxes as it's possible a previous owner has added the wrong oil and this isn't always obvious. Many auto boxes aren't very tolerant to dirty/wrong/contaminated oil.

If the motor is high mileage, might be worth dropping the sump and cleaning out any debris? I've not had to dismantle any of these boxes, but the old GM boxes found in many of the Jags I've owned used to collect quite a bit of grime in the bottom from worn plates etc and some of the oil passages were quite fine tolerance. Presumably there's a filter somewhere and could it just be that this is restricted and causing temporary oil shortage somewhere?

I'd also echo the caution of taking the box apart for parts - changed a clutch in a GM400 for an XJS-V12 I had many years ago... Did it with the help of a friend in the trade and it's not the average DIY job - a bit like an oily pinball machine was my lasting memory!

Thanks for the input guys,

I'm not the rip **** and bust sort of guy, so wading in and fitting another trans is not going to happen till i know what is causing the problem. I still think the problem is electrical, but i am not ruling out the lock up torque converter. The oil looks ok and it is not overfull. It has not had an oil change in the last 50k since i have owned it, but i doubt an oil change will fix it and i am reluctant to change the oil only to find out i have to pull out the box and it is then wasted (i'm tight or thrifty, one or the other).

I will dig a little deeper and keep you posted with the diagnosis and fix when it happens cos i'm sure i can't be the only one out there with these symptoms.

EAS has faulted twice in the last 2 days, just to keep me on my toes. thank you BBS guy for fixing my faultmate, i couldn't be without it.