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auto change down....is this normal?

Posted: Thu Aug 11, 2011 8:13 am
by downward dog
I noticed on the M5 a few days ago that when travelling at about 60-65, if I gently press the accelerator, I get a change down, ease off a bit changes up, hunting around for a gear....I was surprised this was happening at that speed on a motorway cruise, just wondered if that is normal on Bongos ?

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 8:47 am
by dext924
Not had the problem myself on a motorway, what revs are you doing at 60 mph? I find that once I get past 55, unless there is a hill involved, I can pretty much cruise in one gear and it pulls fine. Some one with a little more knowledge might shed a bit more light on the matter

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 8:56 am
by downward dog
Didn't look too closely, I think it was between 2500-3000, I assume the change down is related to rpm rather than speed, other autos i have driven however, dont seem to do this on the motorway unless I ask for 'kickdown'.....?

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 9:19 am
by dext924
Yeah, if you drop down to 1500, it will drop a gear or two. If you are already at 2500, unless you bury the pedal, it shouldn't drop a gear, or unless you engage the hold button. Still a bit of a newbie myself, so can't offer any concrete advice, only that it doesn't sound normal. :?:
Sure someone will be along to offer a more thorough analysis soon my friend, hopefully nothing too serious.....

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 1:10 pm
by nigelgibson
seem to think at a certain speed the gearbox 'locks in' [ bit like overdrive ] so it could well be what you are doing is making it drop out of 'lock in ' mode. member called Alacrity is your man here , he is the gearbox man. If he doen't see the post maybe you could pm him.

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 1:12 pm
by mikeonb4c
If I lift my foot off, even at motorway speeds, the box seems to drop a gear/come out of lockup before going back into lockout/top once I put my foot down again. Not sure if this is connected to your experience but.........

PS - nigelgibson beat me to it! 8)

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 1:18 pm
by Northern Bongolow
it is doing exactly what it should.
the top gear lock up is designed to be load sensative.(throttle sensative).
if there is little load on the engine (little throttle) it goes into (direct drive) to save the torque converter from overheating. when load is applied the throttle position changes the gear down via the ecu.
if you feel its not working at the correct time,either the throttle position sensor,or the fan switch may be a little out of wack.
but to me this sounds spot on.

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 3:48 pm
by downward dog
Good to hear it seems normal, I must say that the gearbox seems fine usually, just as an aside I popped out at lunchtime and chexked the autobox oil level. It is reading considerably above the max mark, and the little lines above the hatched section...a nice clear orangey colour....could it be my importer overfilled it.....does this have any effect ....Hmmmmm ??!!

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 4:54 pm
by dunslair
downward dog wrote:Good to hear it seems normal, I must say that the gearbox seems fine usually, just as an aside I popped out at lunchtime and chexked the autobox oil level. It is reading considerably above the max mark, and the little lines above the hatched section...a nice clear orangey colour....could it be my importer overfilled it.....does this have any effect ....Hmmmmm ??!!
Did you check it with the engine running and in N?

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 6:16 pm
by missfixit70
Static gearbox oil levels are usually above the mark on the dipstick, should be checked with a warm, running gearbox, brakes on, range slowly through the gears & then take the level in P. Check for condition too, if it smells like burnt toast & is dark in colour, probably needs changing, although, most peoples ATF is probably well past needing changing anyway - http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=30096.

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 7:01 pm
by downward dog
Ah! Didn't know that.....I will try it running, the colour is a nice fresh light orange so that's ok!
Thanks all.

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 7:05 pm
by missfixit70
downward dog wrote:Ah! Didn't know that.....I will try it running, the colour is a nice fresh light orange so that's ok!
Thanks all.
As was mine, but if you read the link, it may well be worth changing the ATF anyway, especially if there's no history of it being changed. At least you know that is ok then & less chance of problems in the future.

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 10:10 pm
by M 80NGO
It would be worth checking that your Throttle position sensor is correctly set, its a five min job to do, The TPS is located under the drivers seat on the top of the fuel pump with the ignition on, it should have a closed reading of 1.2v and 4.3v fully open, click the attached link :wink:

http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=50056

Re: auto change down....is this normal?

Posted: Thu Aug 11, 2011 11:34 pm
by Bongoplod
Ive read and re read this afew times in case i missed it,but cant see any mention of what model you have......2.5 diesel,v6 or 2ltr petrol auto.
Ive had 2, 2.5 auto deisels and now own a 2 ltr petrol auto.I had no problems really with my deisels,but the 2ltr petrol goes up and down the gears like a brides nightie,I assume cos its underpowered

Brian

Re: auto change down....is this normal?

Posted: Fri Aug 12, 2011 10:15 am
by downward dog
More info...thanks all....it's a 2.5D 4 wheel drive 1999 AFT. I will check levels running and TPS when it stops raining!