P38 2.5 auto box Puzzler!!!!!!

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Mike v.t.s

Mike v.t.s

Active Member
Posts
475
Location
Chorley, lancashire
Hi every 1, its a bot of a strange 1 and im seriously in the dark about this... il try to explain it as best i can so here goes...
I allways thought my auto box was super, changes very smoothly and goes up and down the gears with no cluncks etc... but today i was in a rush and i hammerd it down the motoway, faster than greased weasel ****, normaly no matter what speed or gear its in if i lift my foot or put it down slightly the revs will slightly go up or down before the speedo goes up or down, normal i thought as my mates V8 is the same, How ever it suddenly found an EXTRA gear :confused: the revs dropped to 2400 at 70 mph and if i lifted or put foot down slightly the rev counter didnt budge just like driving a manual... normaly at 70 its slightly higher etc, i tried changing to third by moving it to 3rd etc as i wonderd if it wasnt engaging 4th but no, everything was working fine.... it has done this before when i very first got the rangie, i was towing a trailer with a shogun on so it got hot, i dont mean over heating or anything bad but she was working hard just like today... is there a 5th gear??? i do no that there a temp sender fron the head thats been unplugged with a new un plugged in and dropped down the side of the engine, i thought it was so she started when hot, but i have noticed somthing else unplugged from the head :mad:.
Is the gearbox controlled by a temp sender from the head so it can tell if its warm enuf to engage top gear?? if this has confused you then its totaly confused the crap outa me :confused::confused::confused: i have checked the oil levels and they are fine, i changed ALL oils except the main box but its still clean looking and theres plenty in. please please can any 1 help... thanks my fellow landy zonerz... :D P.S alltho the temp senders have been messed around with she does tick over when warm at correct engine idle speed... and ive got a cold start majic box fitted...
 
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Torque converter lock up is supposed to occur at 50mph in 4th gear. It sounds as though yours is not locking up. When was the oil last changed? I have discovered that the schedule calls for changes at 30000 miles. If it has not been done, do it. As only half the oil comes out, refill, run, drain again and refill. If you are lucky that will sort it. I'm in the middle of doing mine as I have a shift problem which I hope the oil change will cure.
Re-connect all the sensors properly as temperature does affect things and double check your hot start fix is fitted correctly as that has been know to cause strange problems.
 
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Datatek said:
Torque converter lock up is supposed to occur at 50mph in 4th gear. It sounds as though yours is not locking up. When was the oil last changed? I have discovered that the schedule calls for changes at 30000 miles. If it has not been done, do it. As only half the oil comes out, refill, run, drain again and refill. If you are lucky that will sort it. I'm in the middle of doing mine as I have a shift problem which I hope the oil change will cure.
Re-connect all the sensors properly as temperature does affect things and double check your hot start fix is fitted correctly as that has been know to cause strange problems.
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Ahhhhhh, i get it now didnt no that it was suppost to lock up at 50mph... it makes sence but like i say its only ever done it twice since ive had heer and ive done 4,600 miles lol. ive not changed the gearbox oil... done every other oil :D (inc diffs, eng and transfer etc etc) but main box looked clean so i never did it, just topped it up. If the oil change doesnt cure it is there anything else i should check?? Thanks Datatek you a ledgend...:5bcheers2: :lvheart-119: i was starting to think it was me loosing the plot as it looked like no one had a clue what i was on about. ;)
 
Engine should be revving at 2,620 rpm at 70 mph. If yours is only revving at 2,400 you have definatly found another gear. 2,400 rpm in lockup is 64.08mph. 26.70 mph per 1000 rpm in top gear with torque converter locked up. Unless you have silly wheels on. Or your speedo is doolally.:eek::eek::eek:
 
wammers said:
Engine should be revving at 2,620 rpm at 70 mph. If yours is only revving at 2,400 you have definatly found another gear. 2,400 rpm in lockup is 64.08mph. 26.70 mph per 1000 rpm in top gear with torque converter locked up. Unless you have silly wheels on. Or your speedo is doolally.:eek::eek::eek:
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Lock up is speed and throttle dependent, on a light throttle opening, the DSE lock up occurs at just over 50mph on the 3 DSE's that I have access to. It unlocks on a trailing throttle at just under 50mph. According to the book it is also supposed to lock up in third. That's on 18" Hurricanes.
 
Datatek said:
Lock up is speed and throttle dependent, on a light throttle opening, the DSE lock up occurs at just over 50mph on the 3 DSE's that I have access to. It unlocks on a trailing throttle at just under 50mph. According to the book it is also supposed to lock up in third. That's on 18" Hurricanes.
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We are talking the 70 mph indicated at 2,400 rpm as stated by the OP. Unless the lock has been uncoupled by kick down at that speed the lock should be on. 2,400 rpm @ 26.70 mph per 1000 rpm is 64.08 mph not 70. 2,400 rpm at 70 mph gives a speed of 29.16 mph per 1,000 rpm. That ratio is simply not in the gearbox, so he must have either different wheels on or the speedo is out by six mph at an indicated 70. Nothing wrong speedos do over read at these speeds. It's under reading they must not do.IE: indicating 64 mph when doing 70 mph.
 
Just been reading RAVE in connection with my problem, in section B7 of the electrical trouble shooting section it gives torque converter lock up as any speed above 45 mph in 3rd or 4th gear.
 
Datatek said:
Just been reading RAVE in connection with my problem, in section B7 of the electrical trouble shooting section it gives torque converter lock up as any speed above 45 mph in 3rd or 4th gear.
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Yes mine comes in around 48 mph or so. Your problem sounds like a sticky valve block. One clutch letting go and the next one lazy engagement. On the old boxes it would be strip and clean block and adjust brake bands. But things have moved on a little since those days. Have never been inside one of the newer ones.
 
wammers said:
Engine should be revving at 2,620 rpm at 70 mph. If yours is only revving at 2,400 you have definatly found another gear. 2,400 rpm in lockup is 64.08mph. 26.70 mph per 1000 rpm in top gear with torque converter locked up. Unless you have silly wheels on. Or your speedo is doolally.:eek::eek::eek:
Click to expand...

I agree it just doesnt add up... i did check the speed againstt my sat nav and there was a 1mph differance... when it "locked up" she was doing 32 mpg, when not locked i get 28 mpg... im totally confused...:doh::confused::confused::confused:
 
wammers said:
Yes mine comes in around 48 mph or so. Your problem sounds like a sticky valve block. One clutch letting go and the next one lazy engagement. On the old boxes it would be strip and clean block and adjust brake bands. But things have moved on a little since those days. Have never been inside one of the newer ones.
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Yes that is exactly what it sounds like, lots of stuff on the bimmer forums. Easy enough to strip and clean if the box is off the car, not so easy on your back under the bugger. The ZF4hp22 seems to be an old design that was formery hydraulically controlled, the version on the P38 is ZF4hp22E or EH which stands for electronic control.
 
Datatek said:
Yes that is exactly what it sounds like, lots of stuff on the bimmer forums. Easy enough to strip and clean if the box is off the car, not so easy on your back under the bugger. The ZF4hp22 seems to be an old design that was formery hydraulically controlled, the version on the P38 is ZF4hp22E or EH which stands for electronic control.
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Valve block is reasonably easy to get off. BUT. Don't strip and try to clean unless you have service sheet in front of you. Lots of different rate colour coded springs. They HAVE to be put back in correct place.
 
wammers said:
Valve block is reasonably easy to get off. BUT. Don't strip and try to clean unless you have service sheet in front of you. Lots of different rate colour coded springs. They HAVE to be put back in correct place.
Click to expand...


Oh bugger!! sounds like a garage job... :eek: i hate gearboxes, il change um and service um but stripping them is a big no no... i wont do my customers autobox's... i do anything else and i mean anything but not stripping them, had a bad experiance once and vowed never again :mad::mad: lol. I dont beleive in magic potoins and bottles of fix it BUT if theres a bottle of fix it for this then il try it:D
Is it worth trying changing the oil or is it just putting off the inevitable... ?? and why would it work when i drive her hard on the motoway?? Thanks for all the help and advice so far.:)
 
Mike v.t.s said:
Oh bugger!! sounds like a garage job... :eek: i hate gearboxes, il change um and service um but stripping them is a big no no... i wont do my customers autobox's... i do anything else and i mean anything but not stripping them, had a bad experiance once and vowed never again :mad::mad: lol. I dont beleive in magic potoins and bottles of fix it BUT if theres a bottle of fix it for this then il try it:D
Is it worth trying changing the oil or is it just putting off the inevitable... ?? and why would it work when i drive her hard on the motoway?? Thanks for all the help and advice so far.:)
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Anything is worth a try if it costs less than the £700.00 for an exchange box i suppose.
 
If it's just the troque converter lock up clutch not operating, might be worth getting under it and removing the connector and cleaning it, thats my next job followed by an ECU change. Certainly worth changing the oil, if it looks bad you will need to do it at least twice. I guess you have a ramp and a suitable pump to re-fill, it was a horrible job for me.
I'd have a go at stripping the valve block, but I doubt I could get the box off the car on my back on the garage floor without killing myself.
 
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Datatek said:
If it's just the troque converter lock up clutch not operating, might be worth getting under it and removing the connector and cleaning it, thats my next job followed by an ECU change. Certainly worth changing the oil, if it looks bad you will need to do it at least twice. I guess you have a ramp and a suitable pump to re-fill, it was a horrible job for me.
I'd have a go at stripping the valve block, but I doubt I could get the box off the car on my back on the garage floor without killing myself.
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You don't need to remove box to take valve block off. Just take sump off and valve block is bolted under box. Full removal instructions in RAVE. Unless you have service sheet and maybe a valve block tray remembering where everything goes is the bloody problem.
 
wammers said:
You don't need to remove box to take valve block off. Just take sump off and valve block is bolted under box. Full removal instructions in RAVE. Unless you have service sheet and maybe a valve block tray remembering where everything goes is the bloody problem.
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Yes I know, it's just not a job I would fancy doing on my back. I have a spare 150K miles working box on my spares dog but I don't think I could physically do the job of swapping them over.
Before I get to that stage I'm going to order a filter and change the oil one more time after I've checked the electrics out.
 
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Datatek said:
If it's just the troque converter lock up clutch not operating, might be worth getting under it and removing the connector and cleaning it, thats my next job followed by an ECU change. Certainly worth changing the oil, if it looks bad you will need to do it at least twice. I guess you have a ramp and a suitable pump to re-fill, it was a horrible job for me.
I'd have a go at stripping the valve block, but I doubt I could get the box off the car on my back on the garage floor without killing myself.
Click to expand...


I did have a garage (unit) but i shut it down and went mobile, with the cost of the unit plus electric etc it was costing too much, i make the same mobile without the overhead cost so im limited to heavy duty "normal" ramps and my oil pump is full of EP90.... looks like il av to borrow 1 from my mates garage lol, where abouts is the connector that i need to clean??:doh:
 
Mike v.t.s said:
I did have a garage (unit) but i shut it down and went mobile, with the cost of the unit plus electric etc it was costing too much, i make the same mobile without the overhead cost so im limited to heavy duty "normal" ramps and my oil pump is full of EP90.... looks like il av to borrow 1 from my mates garage lol, where abouts is the connector that i need to clean??:doh:
Click to expand...

Left hand side up near the selector quadrant according to the drawings
 
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