auto change down....is this normal?

Technical questions and answers about the Mazda Bongo

Moderators: Doone, westonwarrior

downward dog
Bongolier
Posts: 185
Joined: Wed Sep 22, 2010 10:45 am
Location: Derbyshire

auto change down....is this normal?

Post by downward dog » Thu Aug 11, 2011 8:13 am

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 ?
dext924

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

Post by dext924 » Thu Aug 11, 2011 8:47 am

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
downward dog
Bongolier
Posts: 185
Joined: Wed Sep 22, 2010 10:45 am
Location: Derbyshire

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

Post by downward dog » Thu Aug 11, 2011 8:56 am

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'.....?
dext924

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

Post by dext924 » Thu Aug 11, 2011 9:19 am

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.....
nigelgibson
Tribal Elder
Posts: 652
Joined: Fri Aug 06, 2010 1:33 pm
Location: n.e. derbyshire

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

Post by nigelgibson » Thu Aug 11, 2011 1:10 pm

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.
User avatar
mikeonb4c
Supreme Being
Posts: 22877
Joined: Sun Nov 05, 2006 10:49 pm
Location: Living with Mango Bongo in the North West but with a tendency to roam
Contact:

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

Post by mikeonb4c » Thu Aug 11, 2011 1:12 pm

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)
User avatar
Northern Bongolow
Supreme Being
Posts: 7722
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

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

Post by Northern Bongolow » Thu Aug 11, 2011 1:18 pm

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.
downward dog
Bongolier
Posts: 185
Joined: Wed Sep 22, 2010 10:45 am
Location: Derbyshire

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

Post by downward dog » Thu Aug 11, 2011 3:48 pm

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 ??!!
User avatar
dunslair
Supreme Being
Posts: 1966
Joined: Sun Feb 01, 2009 9:07 pm
Location: scottish borders

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

Post by dunslair » Thu Aug 11, 2011 4:54 pm

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?
User avatar
missfixit70
Supreme Being
Posts: 12431
Joined: Fri Jun 01, 2007 3:53 pm
Location: weymouth

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

Post by missfixit70 » Thu Aug 11, 2011 6:16 pm

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.
You can't polish a turd - but you can roll it in glitter.
downward dog
Bongolier
Posts: 185
Joined: Wed Sep 22, 2010 10:45 am
Location: Derbyshire

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

Post by downward dog » Thu Aug 11, 2011 7:01 pm

Ah! Didn't know that.....I will try it running, the colour is a nice fresh light orange so that's ok!
Thanks all.
User avatar
missfixit70
Supreme Being
Posts: 12431
Joined: Fri Jun 01, 2007 3:53 pm
Location: weymouth

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

Post by missfixit70 » Thu Aug 11, 2011 7:05 pm

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.
You can't polish a turd - but you can roll it in glitter.
M 80NGO
Supreme Being
Posts: 1913
Joined: Wed Sep 01, 2010 9:24 pm
Location: Usually in My own wibbly wobbly lill world ! Otherwise Huntingdon.

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

Post by M 80NGO » Thu Aug 11, 2011 10:10 pm

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
User avatar
Bongoplod
Supreme Being
Posts: 3655
Joined: Wed May 09, 2007 7:03 am
Location: Wiggin,Lancyshire.

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

Post by Bongoplod » Thu Aug 11, 2011 11:34 pm

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
Confucious once said " To be fluent in Bongolese is to hold the key to the world!"
downward dog
Bongolier
Posts: 185
Joined: Wed Sep 22, 2010 10:45 am
Location: Derbyshire

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

Post by downward dog » Fri Aug 12, 2011 10:15 am

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!
Locked

Return to “Techie Stuff”