G Wagen Transmission

[flat6buster]

Could someone intelligent please help me out with what is going on?

Twice I have got into our G Wagen from cold and pulled gently away. It feels as though there is clutch slip (it is automatic).

I check the tyres and find one rear wheel is low on pressure (I think one has a slow puncture).

On inflating the low tyre the feeling of a slipping clutch disappears.

I imagine with such enormous sidewalls a reduction in tyre pressure makes a big difference in rolling radius across the axle but I would like to know why that results in a feeling of clutch slip (sorry the only way I can think to describe it).

Or is the feeling not going away once reinflated, the amelioration is all in my head and my gearbox is about to be toast (but with not even 70,000 miles I think this unlikely).

Thanks in advance.

 

[V12]

Have you checked the ATF? Should be red, not brown and should not smell of any burning.

 

[boxbrownie]

Possibly the G has a clever traction control which sees an difference in wheel speeds and assumes there is wheel slip and is moderating the transmission for the conditions it thinks there are?

Or..............maybe not?

 

[flat6buster]

Have you checked the ATF? Should be red, not brown and should not smell of any burning.

yes I did wonder, I asked at a local Suzuki garage to check it and they said (after a day) that they were unable to.

May have to travel I guess.

 

[V12]

Suzuki garage sound stupid.

Pull the dipstick out, check level, wipe it on a clean white cloth so you can really see what colour the fluid currently is and give the oil a good smell.

 

[flat6buster]

Suzuki garage sound stupid.

Pull the dipstick out, check level, wipe it on a clean white cloth so you can really see what colour the fluid currently is and give the oil a good smell.

Thank you I will have a dig around.

Yes the Suzuki garage proved themselves to be dipsticks.

 

[boxbrownie]

Don't know how old or what engine exactly you have but if its similar to my ML engine there is no transmission dipstick............so Suzuki may not have been as thick as you think

Then again they probably are anyway

 

[V12]

Presumably it's the 280ge he has listed as one of his vehicles, which means it's probably from the 80's and definitely has a dip stick.

 

[boxbrownie]

Presumably it's the 280ge he has listed as one of his vehicles, which means it's probably from the 80's and definitely has a dip stick.

In that case it also is highly unlikely it's anything to do with clever electronic traction control also..........

 

[grober]

If you have the hydraulically controlled 4 matic system it uses a number of sensors to make decisions
individual front wheel speed [ shared with ABS]
common rear axle speed
steering angle from the steering wheel
brake light switch

The heart of the system is the hydraulically controlled trans-axle differential- this is tasked with locking the centre diff and engaging FWD.
By default the car starts in mode 1 with 35 %front 65 %rear drive--- its to aid pulling away---- after 16mph if everything is well it reverts to mode 0 - rear wheel drive.
If a severe lack of traction occurs = wheel slippage= different wheel speed detected [outwith set parameters]--- the system can switch to mode 2 50% front 50 %rear or finally mode 3 50 %front 50% rear + rear diff locked ---at any time.
My guess is that on moving off the system is detecting what it thinks is wheel slippage and is either holding on to mode 1 or even momentarily switching to mode 2 or 3 .
the system is robust but quite sensitive to different wheel speed . CAR OWNERS have been caught out by merely having different treaded tyres front and back in the past.
Conclusion- if after blowing up the rear tyre things are OK probably nothing to worry about. HOWEVER a comprehensive fluid check all round would not be a bad idea to include your autobox and the 4matic hydraulic reservoir is at the correct level.

ps what you are feeling are infact drive clutches engaging and disengaging- this would not be apparent in true slippery conditions because there a true degree of wheel slippage would exist and not just the "semblance " of one

 

[V12]

4 matic on a 280GE? It has manual diff locks.
I don't think the 280GE even got the option of ABS, I think that started with the 300GE.

 

[boxbrownie]

In that case it also is highly unlikely it's anything to do with clever electronic traction control also..........

Aha....so maybe I was on the right track......just not fully electronic.

 

[boxbrownie]

4 matic on a 280GE? It has manual diff locks.
I don't think the 280GE even got the option of ABS, I think that started with the 300GE.

Oh well.......

 

[jaymanek]

i cant see the low pressure causing slipping.. what I can imaging is low fluid causing issues, I would check the level asap..

Car running, on flat ground at full operating temp. The dipstick is the one with the red top, the level must be near the second line up. If you need to add any its done through the dipstick tube. Only fill around 500 ml at a time and wait for it to settle before checking again.

 

[flat6buster]

I wanted to say thanks to all for your replies. Culprit was indeed low gearbox oil and I am pleased to say that Gertie the G is running like an absolute bomb once more. Defender drivers need to run for cover again. ......