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spadgr

spadgr

Active Member
Posts
210
Location
wellington, porirua NZ
Gidday,

I have a couple of queries with regard to the transmission shifting on my rangie. I have noticed over the last month or so that when i am cruising at around 110kmh (65-70 mph) the trans seems to drop down a shift (or the lock up converter drops out) for no apparent reason. No change in throttle position or gradient, it just seems to drop a shift for a couple of minutes and then shift back up. It did this several times over 1000km round trip and then it has been ok for the last month. Then again the other day it didn't want to make the final shift for a couple of km's so the engine was revving higher at cruising speed.

Since i have had the rangie, the trans shifting has always been a little odd from 3rd to 4th uphill always seems to be about 4 shifts, i assumed it was 3rd, 3rd lock up, 4th, 4th lock up. Is that how it works? or have i got problems.
 
It would help if we new what car & engine. P38 4ltr or 4.6 petrol have different gearboxes or is it a diesel? When did you last change the oil & filter. If it's a P38 the LR schedule calls for an oil change every 30K miles.
 
Its a 2.5 dse. I don't know when the oil was changed last as i have only done about 15k but no records from previous owners. Would dirty oil cause the symptoms i have described?
 
Dirty oil will not help, but the gearbox is marginal on the diesel and the clutches fail as i have found out to my cost. If you are lucky, new oil and filter may sort it, it's worth a try.
 
its been said on here alot so you can do a search if you like and bear in mind I am a classic man not a p38 guy but:

the detergent in the new oil loosens all the silt built up from years of use in your box and blocks the govenor this stops it form changing up , especially when cold.

you can remove and replace the govenor but this is a transfer box off job and then as soon as you go for another long drive it stirrs it all up again and it happens again.

only solution, recon the box. have a look on the FAQ'S on the ashcroft transmission site f you dont believe me.

it also happend to me, by the time all bills were in inclduing wasting £300 on the govenor change,****ing about and a recon I was down £1400 :doh:

just run it till it wont run anymore and have it recond or fit a used one (which may be no better)

I would say that if yours is playing up now the clutch packs may be breaking up already and blocking the govenor slightly, you will only make it worse. ensure if any replacement is fitted the whole line and cooler assmebly is flushed first with kooler cleen or the bits will get into the new box.
 
p38s dont have govenors,theres never much silt ,but govenor can stick as you say but is easy fix,ive done quite a few .if you fitted new that still failed either faulty part or clutch debris etc which would be other fault not just oil change
 
well two things, read ashcrofts cos they know best and yes I agree its clutch debris as will be to some extent in all old boxes but detergent in new oil cuts the silt loose.

so do gay38 boxes not have the centrifugal govenor in the 4hp22 then?
 
even old box dosent have that much silt if in good order but still can be effected govenor wise by change ,which is easy fix normally new one will allways cure unless the oil change was by chance at the same time as other fault that was putting more debris in oil ie clutch pack,i dont need to read ashcrofts site ive been rebuilding them for over 20 years and have long known about this,if govenor is worn new oil may make it stick till hot if not it wont ,but to keep sticking govenors something else rather than oil change is occuring
 
my orginal statement still stands

no offence but if you were as good as ashcrofts we would have heard of you like we have of them.

and better he knows the risks before he does the oil.

best we agree to differ on this 1 m8
 
knowledge of gearboxes etc is different than business success,there are hundreds of gearbox rebuilders that are better than me or ashcrofts thats a stupid statement,p38s dont have govenors as they are electroinically controlled so are unaffected in the same way ,through lack of knowledge you have misunderstood reason why ashcroft says what he does
 
again orginal statement stands , as I said in it and later I am talking about a classic box if it applies tot he p38- I did not say it did
 
OK James, I have noticed some of your past replies in other threads re auto transmission problems, and it appears to me you know what you're talking about. What do you think my problem is? Do the torque converters lock up in 3rd and 4th when under load, if not then why do i seem to get 4 shifts from 2nd to 4th lockup when under steady acceleration on the flat or uphill?

When it is cold, the shifts from all gears seem to be quite long, ie high revving but with some manufacturers that is a design characteristic to bring the oil up to running temperature sooner, but i don't know if that is a true of the 4hp22, i just assumed it was. It could be a dirty governor as you mention.

What about the trans dropping a shift, whilst cruising and then shifting back up again after a couple of minutes? The trans did this several times over an hour on a four hour drive, i had been driving for 2 hours before the first occurrence. It seems to me as though the lock up torque converter is dropping out and then coming in again. Could this be an electrical problem?

Cheers spadgr
 
spadgr said:
OK James, I have noticed some of your past replies in other threads re auto transmission problems, and it appears to me you know what you're talking about. What do you think my problem is? Do the torque converters lock up in 3rd and 4th when under load, if not then why do i seem to get 4 shifts from 2nd to 4th lockup when under steady acceleration on the flat or uphill?

When it is cold, the shifts from all gears seem to be quite long, ie high revving but with some manufacturers that is a design characteristic to bring the oil up to running temperature sooner, but i don't know if that is a true of the 4hp22, i just assumed it was. It could be a dirty governor as you mention.

What about the trans dropping a shift, whilst cruising and then shifting back up again after a couple of minutes? The trans did this several times over an hour on a four hour drive, i had been driving for 2 hours before the first occurrence. It seems to me as though the lock up torque converter is dropping out and then coming in again. Could this be an electrical problem?

Cheers spadgr
Click to expand...

Nothing to lose by getting the fault codes read and it's certainly worth checking out all the connections given that the wiring on the P38 is so prone to failures.
There is no governor on the ZF4HP22E electronically controlled gearbox it's all done by the ECU, so it could also be an ECU problem or even a sensor problem.
 
jamesmartin said:
so what your saying is you dont know anything about the gear boxes read what someone else has said ,fair enough
Click to expand...


And what happened to me, and cost me! just trying to help him but said at the beggining its all classic stuff with me- gay38's not my thing!
 
the point been was that changing oil wasnt the cause of your fault obviously it had other issues otherwise another govenor would have fixed it
 
in that case both my rebuilders and ashcrofts differ in opinion from you.so do I.

I would think most 4hp22's pulling 2.5 range rovers about for 20 years would have some "issues" though- wear and tear.

But as I said yesterday we should agree to differ as this discussion is pointless, especailly as I now run and lt95 and this thread about a p38 with a new fangled govenor
 
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