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MG MGF Technical - Gear change issue

Hi all,

Wonder if anyone can help as I have come across a few possibilities for this problem?

Basically my '97 MGF VVC is having trouble changing gears. this appears to get worse as the engine warms up (which seems to be happening quicker recently, I assume due to the warm weather). When cold I can get into reverse with only a slight bit of force. When warm I have to grind it into reverse and all gears take a bit of force to drop in (No grinding though) but the 5th gear becomes much more difficult. The gears are clunking into place.

I have checked the engine oil and coolant (for the engine warmup) and these are fine. The clutch level was a little low (just above the blanking plate) and I have topped this up with D4.

I have come across articles for cables, gearbox oil, slave cylinder issues, but wonder if anyone can determine these symptoms before I have to put it in the garage and get charged a fortune just to find the problem! My thoughts are that the gearbox oil is low, but I don't have any ramps to check this (hence the garage). I have had a look at the slave cylinder and there appears to be a good 2cm push of the piston, although I do have a slave cylinder repair kit if needed.

Thankyou in advance

David Cunningham
D J Cunningham

Hi David

I don't know that I can offer a great deal of advice other than to say that the F is renowned for being difficult to engage reverse gear! The percieved wisdom is to select 1st or 2nd initially and then to reverse from there. However, you mention 'trouble changing gears', inferring more than just reverse.

After I bought the TF, I always felt that the gearchange was stiffer than that on my old F. I suppose I mentally put this down to the fact the car had been standing for several months and would loosen up after a few miles. That wasn't to be however, and I took the opportunity to have the gearbox drained and refilled at the MOT/Service this year which, yes, has made a difference, but not to the extent I had hoped it might. I will be looking at the cables next, but quite frankly it doesn't register that high on my list of must-do jobs. On the TF it's a minor irritation, but sounds as if it could be more of an issue for you. Have you checked the clutch arm throw is the same when both cold and hot? That, and the gearbox oil level, are the two obvious starting points.
Mike Hall

The fact that the problem gets worse as the engine warms up is I think significant. If the clutch release arm is binding in the tunnel on the gearbox casing, the expansion of the alloy as the engine heat soaks across will make it worse. While 2cm of slave arm travel ought to be enough, some of that effort may be being lost due to the slave cylinder flexing on its mounting.

With the engine up to temperature, try disconnecting the clevis pin between the slave actuator arm and the clutch release arm and see if you can manually move the arm further than the slave is managing. There's very stiff resistance so the scissor jack and some lengths of wood is the technique I use. If you can manually disengage the clutch better than the hydraulics can, i.e. no crunching (except maybe on reverse...) then the suspects are either the hydraulics or the release arm. If you find seeped fluid around the bottom of the slave cylinder, then the seals have failed and need to be renewed. But in my experience the slave cylinder only fails when it's put under excess workload, i.e. release arm seizing. There's no provision for lubrication of the arm, but dribbling engine oil onto the point where it disappears inside the gearbox casing while the clutch pedal is repeatedly pressed may, if you're lucky, get some oil down the shaft. If you're unlucky the seizure point will be down near the bottom of the tunnel, and the only solution is to split the gearbox away from the engine and remove the arm completely and replace, ideally with one with a grease channel (Mike Satur supplies these). That's quite a lot of labour (understatement alert...) so fingers crossed ;o)
bandit

I do believe that the alloy will expand greater than the steel shaft thereby increasing any clearance and releasing the shaft. This is what is normally reported.
When applying any lubricant, the oil should be hot allowing the increased clearance to accept the oil.
Geoff F.
Geoff Farthing

This thread was discussed between 03/06/2010 and 04/06/2010

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