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MG MGF Technical - Stepspeed / Steptronic Problems

Hi,

Thanks for taking the time to read this, this is my first post on this forum as I have just purchased an MGF.

I bought the car in the knowledge that it needed some work including, a new hood, some minor paintwork and most importantly the gearbox is stuck in one gear.

I have purchased a rover technical manual on e-bay that covers the gearbox however it is does not help me with my particular problem which is as follows:

The 'gear' selector can be operated to allow the car to drive forwards or backward, it selects all of the correct modes and the dashboard indication is correct for the position of the 'gear' selector. When stationary in manual mode the display can be made to read either 1st gear or 2nd. Once moving you can use the 'gear' selector to increase the gear number on the dashboard all the way up to 6th. I understand that this is normal as the electronics prevent you manually engaging a gear above 2nd to pull away to prevent damage to the transmission.

The gearbox fault indication light does not illuminate under any conditions and hence I assume that the engine management is not recording any faults.

I have checked the resistance of the stepper motor which controls the ratios, this is 28ohms on each coil (the value should be 18-30ohms apparently so this appears ok)

When on the road the car struggles to pull away (to the point of being downright dangerous at junctions)and accelerates slowly to around 40-50 when it then drives fine, above 50 the engine is then reving to high (presumably 40-50 is the normal speed for this gear).

The fluid is topped up to the full mark on the dipstick. It is yellow/beige in colour (similar to ordinary engine oil in clour) however it smells a little bit like gear oil (it's not thick enough however)

My questions are two fold:

If the electronics are faulty, the rover manual and previous posts I have read on here suggest that the dashboard display would not work and the gearbox failure light would appear.

If the fault is with the gearbox, given its nature would it still not work even slightly? The hydraulic pump must surely still be working to hold the CVT pulleys in position and tension the belt to allow the car to drive as it does, the stepper motor which tests ok for resistance may not be adjusting the valve or what ever it does I surpose.

I am intrigued by this gearbox as the concept of its operation is fantastic and I would love to make it work again. I have an offer of a secondhand gearbox at a reasonable price but don't want to change the gearbox only to find its was something on the electronics side.

Does anyone have any experience with these gearboxes or has experienced any similar problems.

I have found a receipt in the car for a gearbox rebuild 9000 miles ago. However this was in 2004. The car has currently done 51k.

Any help that anyone can give me would be greatly appreciated.

Regards

Andrew Smith





A D Smith

Andrew,

I've heard stoties of the CVT gearbox acting rather strange it the correct fluid is not used. The colour of the fluid in my car is red and is similar to that used in PAS boxes. It might be worth trying to see if changing the fluid helps. As far as I'm aware the correct stuff can only be bought in 5 ltr containers and it cost about £28.
David Clelland

David,

Thanks for your reply, do you know where I can purchase the correct fluid, I went to my local motor factors but they just sold me some ATF Dextron II fluid!

Regards

Andrew Smith
A D Smith

try this link below. ask for guy he has a mass on info

http://www.opieoils.co.uk/lubricants.htm

he help sort out my oil ' cooling ' problems



gerry
gerry

The recommended fluid from the workshop manual is Esso EZL799 or Unipart CVT. However, when I went to my local MG parts counter I was sold Esso High Performance CVT Fluid. Initially the lad was going to sell me a litre of Esso CVT Fluid (I just wanted some to top up gearbox), but another chap said that that wasn't suitable for the MG and I needed the high performance fluid. Unfortunately that only came in a 4 litre container (not 5 as said above) and cost £27 or £28. I thought that it wouldn't go wrong and would be handy for the future. Try the link that Gerry has shown above if you can't get it locally. I know that he bought some for his wife's ZR 120 a while ago.
David Clelland

Andrew,
You do not say how it works in normal 'Automatic' in 'D' or 'Sport' without selecting Preselect.
It is doubtful that it is mechanical or electronic problem but the mechanical bits in between, ie the electrical connectors will cause the majority of your problems.
Geoff F
G. Farthing

In normal automatic mode it is still stuck in one gear.

I have now sourced and fitted a second hand gearbox which appears to have sorted the problem.

When I removed the old gearbox,the oil thatI drained from it was normal oil coloured (not red) and was quite thick. I can only assume that when the car was serviced they changed the oil for the wrong type which has worn somthing in the gearbox. The oil in the bowl is jet black like it has come out of the engine!

Thanks to everyone who responded to my first post. I will shortly be stripping the old gearbox to find out what was wrong with it, if I come to any conclusions I will post them.

Regards

Andrew Smith
A D Smith

Pictures please!!
Will Munns

This thread was discussed between 18/08/2006 and 22/08/2006

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