Mk2 2.8 speedo/gearbox fault

[joker777]

Im posting this for dragon & family who is at this moment sat at blyth services wating for an RAC recovery bloke to rescue them

The symptoms are this :

the speedo needle starts to jump and stick and when it does this it appears to hold the gearbox in low gears , now i know that the speedo is electronic and the gearbox takes its prompt to change from this but has anyone had a symilar fault? and what have you done to rectify it?

We thought we had sorted it earlyer when i found a broken wire in the footwell that we thought went to/from the speedo so i solderd it up and we went for a short run to test it and everything was ok but unfortunatly the problem ase re appeared on the way home.

Any help will be appreciated thanks.

[craig]

Haven't got a clue, but hope they get sorted

[Br00n1e]

what a pain for them, did you use dissolving solder?

[dragon]

cheers for the post steve mate just got home and now 00.30am the truck is ok until the speedo starts to fluctuate then it goes bonkers and then shuts the speedo down .
the gearbox then cant make its mind up wot gear to put its self in so stays in the lower gears but randomly changes up n down so i have to build up to 3000 rpm then stick the box in hold to keep it there but the revs still go up n down with the box.

does anyone have any idea wot colour wires behind the dash i could need to look at as i think it might have been a pulled wire when i removed the steering column to sort the steering shaft bearing out .
failing that where do i look for any sensors relating to gearbox and speedo sensors that are linked.
your help would be most appreciated at this time .
thanks in advance

[dragon]

well time to have a look at the problem but not sure where to start .
feel a bit lost with this one .
can anyone help with pics of electrical parts and there locations to look at as the haynes manual is no good and doesnt help at all with electrical side of things

[dj-phatphunker]

YES AT LAST !!!!  sorry to sound harsh ... 

Mine does the same bloody thing only intermitantly and normaly when hot or muddy !!!

few things i have been told over the last few months

best thing to do mate is either PM your number or get mine from my website and give me a ring

I had a really good Chat with a other fourm member who knows loads about these and he has given me a few other things to look at

Give me a ring as its far to much to type lol

Neil

[dragon]

ive spoken to j.m autos (johnny pajero) and they are saying it is a very common fault its either the speedo head thats to fault or its the hexagonal sensor with the wires to it at the gearbox near the propshaft or drive shaft i think he said .(he did say passenger side tho)
about £50 for the sensor or £80 for the speedo head plus vat and fitting .
no more than £150 to rectify 

looks like its a very common problem and thats the cost for second hand parts not new .
now booked in at jm autos for thursday  afternoon so fingers crossed

[craig]

Phew, good news that they've got an idea of what's wrong.  Now lets hope it's the £50 part and not the £80 one!!

[dragon]

still going to try get to kirton but very much doubt it ,
pitty as it sounds like its guna be a great turn out

[TinyTim]

Good to hear you have it sussed.

My guess would be speedo head was shorted at some time after working on the radio then.

Keep us posted mate.

[Br00n1e]

or water ingress into unit on side of gearbox from offroadin

[craig]

or water ingress into unit on side of gearbox from offroadin

That sounds the most likely

[shoggyv6]

i would go with that one too. i had a similar fault on a vw bora i had and all it turned out to be was water in the speedo sensor plug creating a short circuit. dried it out and put some duck oil penetrating fluid in it problem sorted. i would try this first daz before spending any cash mate.

[dragon]

i know roughly the location of the sensor but does anyonr have a clear pic so i know i get the right one,
i personaly think its more likely to be the speedo as the gearbox doesnt play up untill the speedo starts going mental ,
surely if its the sensor on the box it would start the problems the opposite way round

[dragon]

so where is the original speed of the vehicle sent from in the first place .
is the speed reading actually produced at the gearbox to start with.
just trying to understand the layout as i dont know on this motor.
if so then i would say your probably right saying the sensor.