Possible gearbox or transfer problem need help diagnose it

Have done a fluid change and filter as well didn't find any metal just a bit dirty as you would hopeI reset the valves on the computer. Filled it at the right temp and level Still no drive the software is up to date.the torque converter is staying open and the clutch packes aren't getting any pressure when in any gears it doesn't want to hunt in park anymore. The pump is working fine as I was able to fill the gearbox with the same amount of oil as I got out I'm starting to really think that it a wiring fault is their any way I can lock the tour converter up with the IIDtool to test it or is their a manual way to test it. Or is it simply a case of put another one in, it was replaced when it was rebuilt so I don't think it's the problem more likely the valve body or electronic i.e wiring harness as it was just pushed up on top of the gearbox when it was refitted after the rebuild.....any thoughts from anyone are greatly appreciated at this stage.

Using Sport mode, does the selected gear show in the instrument cluster?

Can you change between high and low range and back again?

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Originally Posted by Graeme

Using Sport mode, does the selected gear show in the instrument cluster?

Can you change between high and low range and back again?

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Thanks for getting back to me the answers is yes low range and special features still work and in sport mode the gear selected show on the instrument cluster

I was thinking that if the transfer case is changing then its input shaft is turning, but not necessarily so. However that the gears are showing in the display makes me think its a failed gbox to TC spline, only proven by removing the TC.

How did you arrive at the conclusion that the gbox clutches weren't operating?

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Originally Posted by Graeme

How did you arrive at the conclusion that the gbox clutches weren't operating?

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Thanks Graeme I was running live data on the gearbox I ran it on everything from the torque converter to oil pump whatever it would give me data on both of my computers on it a snap-on running the newest up dates and IID control tool by Gap latest update as well.

In all my years on working and playing on cars when a shaft spline or coupling fails I have always herd some type of noise when it happened or during testing of it and their isn't any that I can hear by ear or with a mechanic stethoscope

If no faults are recorded by the gbox then I very much doubt that there is a problem with the gbox internals or any of the electrical circuits between the gbox and the rest of the vehicle. The gbox in my D4 produced lots of faults when clutches didn't lock within their allowed very short times.

If clutches aren't being operated then it sounds as though the gbox electronics must be waiting for some condition to occur, which if the splines are stripped then the free-spinning o/p shaft that won't be causing any load to be registered combined with the vehicle not moving might be the culprit, although this is probably unlikely.

If the front and rear tail-shafts are detached from the TC flanges or possibly even just one then you might feel attempted drive at the flanges even if the splines are stripped. Alternatively with one tail-shaft disconnected and the TC in high range, turn the detached flange to feel/listen for whether the gbox is also being turned or not.

Hi all

had a bit of a win

Cleaned up all off the electronic connections on the gearbox, transfer and the ones around the battery and CPUs for the transfer that are behind the battery which two of the connectors had medium crosion on them and so did the CPU they cleaned up to a good standard.
I jumped in and gave it a test no change but when I started to go though the off road settings and the high and low selector switches and running through the gears and sport mode their was a big bang and a screeching noise.
I was in neutral when I clicked it in to drive the noise stopped and it moved forward under power and same in reverse but when it is in neutral or park it now makes a noise like (straight cut gears) noise but drives I ran it up and down the street for a little bit but not fast enough to go up and down in gears .
After a but more head scratching checking wireing and cleaning the gearbox and transfer connectors again it still is makeing the same noises the into F mode but I can't get any codes to come up.... I have even loosened of the gear selector cable incase it was out off adjustment and causing it.
So some type of win and fail, anyone has any ideas on the new development was as am a bit puzzled by the new noises but an still thinking something inside the gear box but how it was before this all started doesn't fit with this either

Thanks
Kynan

Bit more off a win drove it a little bit last night after I updated the software for the box and transfer gear changes are slower than before but that could be the software re learning it will go into F when ever I select reverse which has me stumped. But if I stop the car and turn it off and the on again it resets and the gearbox in back to normal so to speak.

I will do another filter and oil change on the weekend to see if I get anything out of it I am still not game enough to drive it more than a couple of blocked from home

Has anyone any ideas why it would be going in to F mode when ever I select reverse and not show any codes it would be a big help

Thanks
Kynan

Has the IIDtool been set to show all fault codes? IIRC as supplied it doesn't show all faults.

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Originally Posted by Graeme

Has the IIDtool been set to show all fault codes? IIRC as supplied it doesn't show all faults.

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I have it set to show all pending and fault codes. Should I have it set for any more.if so what ones should I click in the advance menu