Cold start-problems auto changing gear

Technical questions and answers about the Mazda Bongo

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Bodiebongo
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Cold start-problems auto changing gear

Post by Bodiebongo » Wed Jan 16, 2013 9:07 pm

Hi, I have noticed that these cold mornings/evenings are having a problematic affect on my bongo. I am a total novice so not sure if this is 'normal'. The auto gear box struggles to change up to the highest gear ( I only ever seem to count 4 changes, again not sure if this is normal). It takes a good 3000 revs at 5+mins and 50KPH+ before it changes. This is much quicker and smoother when the engine is warm. Is this normal? Is there some kind of automatic gearbox fluid that I might need to top up?
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Re: Cold start-problems auto changing gear

Post by scanner » Wed Jan 16, 2013 9:11 pm

Entirely normal the gearbox will not lock up in top until the engine and box are up to a reasonable temperature - it usually takes at least a mile or so when the weather is warm and can take much longer this weather.
Bodiebongo
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Re: Cold start-problems auto changing gear

Post by Bodiebongo » Wed Jan 16, 2013 9:22 pm

Thank you! You have put my mind at rest, didn't want something to go wrong!!
Darkstar
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Re: Cold start-problems auto changing gear

Post by Darkstar » Wed Jan 16, 2013 9:31 pm

Yeah, had the same worry when i got mine, didn't like the idea of doing 50 at 3000 rpm, so now its S*d the impatient fool behind me I'm doing 40, although the length of time varies to when it decides to "lock up" normally about a mile or two up the road.
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Northern Bongolow
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Re: Cold start-problems auto changing gear

Post by Northern Bongolow » Wed Jan 16, 2013 11:17 pm

the top gear lock up is governed by temp, if you let the engine and box warm up as much as possible before moving off this will help. this is partly why the winter pack is fitted,it makes everything warm up quicker so saving fuel.
forward movement cools through the front rad so slows the warm up process. also when the engine is revved above about 900 revs the glow plugs turn off, again not aiding warm up.
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helen&tony
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Re: Cold start-problems auto changing gear

Post by helen&tony » Thu Jan 17, 2013 6:14 am

Hi
Agree about ignoring idiots who want to mate with your rear bumper...they can kiss off...DON'T run the motor over 2000 RPM 'till the gears change properly, and the engine's warm. I leave the engine idling for as short while, and toodle slowly to the main road, then keep the revs down 'til I'M happy...not the idiot hanging on the bumper.
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winchman
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Re: Cold start-problems auto changing gear

Post by winchman » Thu Jan 17, 2013 9:24 am

Well I have just logged on to ask that very question, put my mind at rest too
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Driver+Passengers
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Re: Cold start-problems auto changing gear

Post by Driver+Passengers » Thu Jan 17, 2013 10:22 am

This is ECU controlled. I think there are two temperature thresholds that govern the top gear - I get about a mile before it moves into fourth and another mile before lock up, roughly speaking.
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teenmal
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Re: Cold start-problems auto changing gear

Post by teenmal » Thu Jan 17, 2013 2:30 pm

This is one of the reasons they fit a Warm up Valve system to vehicles for cold weather, save wear and tear and Fuel.
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