4wd light on when change 2 front wheels - Mazda 6 Forums : Mazda 6 / Mazda Atenza Forum

swanso · 08-24-2009, 06:38 AM

Hi !

sorry about my english, i'm from spain.

yesterday i changed two frontal wheels on my m6. It has the same dimension like rear, 225, 40 18. During some miles 4wd light was on, later on, it was off, and again on/off about 10min each one.

what is the problem ? have i to change the four wheels ? or with some miles it turns off ?

thanks, forum has a lot of information for me.

regards

kmh001 · 08-24-2009, 07:22 AM

The 4wd system only has two reportable failure modes; 1. system fault and 2. diff over temperature. There is no centre differential, so front to rear rotational variation needs to be accommodated by slipping of the clutches in the diff coupling.

Given that the 4wd warning light coincided with the fitment of two new tyres I would guess there is now enough variation in front to rear rotation rate to over-heat the diff coupling.

You really need to replace all four tyres at the same time on these cars. If you can't afford two more tyres to match the new ones at the front, you could install a diff switch and turn off the rear diff when driving on the highway, which would prevent it over-heating. Good luck.

swanso · 08-24-2009, 07:35 AM

QUOTE (kmh001 @ Aug 24 2009, 01:22 PM)

Quote:

You really need to replace all four tyres at the same time on these cars. If you can't afford two more tyres to match the new ones at the front, you could install a diff switch and turn off the rear diff when driving on the highway, which would prevent it over-heating. Good luck.[/b]

the two new tyres are at the front and arent bad, they have good use.

thanks for your comments.

kmh001 · 08-24-2009, 07:43 AM

The reason you need to replace all four tyres when they wear out is to keep the rolling circumference of all wheels roughly the same. This will prevent the diff over-heating.

bova80 · 08-24-2009, 07:59 AM

can't just replace 2 tires on awd, gotta replace them all.

swanso · 08-24-2009, 08:04 AM

I just telephoned technical service and saids it was normal and in a few miles it desapears. Well, i'll tell you again in a few miles.

In other haldex car like golf R32 or volvo s60 R you dont have to change 4 wheels.

thanks !!

bova80 · 08-24-2009, 08:06 AM

ha its definitely not normal. how many miles are on the rear tires? what is the difference in tread depth?

don't be cheap, replace all 4 or you'll be replacing your differential.

swanso · 08-24-2009, 08:09 AM

it has about 5500 miles ( 9000 km )

08-24-2009, 07:59 AM	#5 (permalink)
bova80 Mazda Guru Join Date: Mar 2007 Location: Pittsburgh, PA Posts: 3,795 Thanks: 0 Thanked 3 Times in 3 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	can't just replace 2 tires on awd, gotta replace them all. __________________ 07 Mazdaspeed6 GT MzdSpd.com

08-24-2009, 08:06 AM	#7 (permalink)
bova80 Mazda Guru Join Date: Mar 2007 Location: Pittsburgh, PA Posts: 3,795 Thanks: 0 Thanked 3 Times in 3 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	ha its definitely not normal. how many miles are on the rear tires? what is the difference in tread depth? don't be cheap, replace all 4 or you'll be replacing your differential. __________________ 07 Mazdaspeed6 GT MzdSpd.com

08-24-2009, 06:38 AM	#1 (permalink)
swanso Learners License Join Date: Jul 2009 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	Hi ! sorry about my english, i'm from spain. yesterday i changed two frontal wheels on my m6. It has the same dimension like rear, 225, 40 18. During some miles 4wd light was on, later on, it was off, and again on/off about 10min each one. what is the problem ? have i to change the four wheels ? or with some miles it turns off ? thanks, forum has a lot of information for me. regards

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08-24-2009, 07:22 AM	#2 (permalink)
kmh001 Track Racer Join Date: Apr 2006 Location: Wollongong Posts: 221 Thanks: 0 Thanked 2 Times in 1 Post Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	The 4wd system only has two reportable failure modes; 1. system fault and 2. diff over temperature. There is no centre differential, so front to rear rotational variation needs to be accommodated by slipping of the clutches in the diff coupling. Given that the 4wd warning light coincided with the fitment of two new tyres I would guess there is now enough variation in front to rear rotation rate to over-heat the diff coupling. You really need to replace all four tyres at the same time on these cars. If you can't afford two more tyres to match the new ones at the front, you could install a diff switch and turn off the rear diff when driving on the highway, which would prevent it over-heating. Good luck.

08-24-2009, 07:43 AM	#4 (permalink)
kmh001 Track Racer Join Date: Apr 2006 Location: Wollongong Posts: 221 Thanks: 0 Thanked 2 Times in 1 Post Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	The reason you need to replace all four tyres when they wear out is to keep the rolling circumference of all wheels roughly the same. This will prevent the diff over-heating.

08-24-2009, 08:04 AM	#6 (permalink)
swanso Learners License Join Date: Jul 2009 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	I just telephoned technical service and saids it was normal and in a few miles it desapears. Well, i'll tell you again in a few miles. In other haldex car like golf R32 or volvo s60 R you dont have to change 4 wheels. thanks !!

08-24-2009, 08:09 AM	#8 (permalink)
swanso Learners License Join Date: Jul 2009 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	it has about 5500 miles ( 9000 km )