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MG MGB Technical - tranny problem

had a clutch installed,seems to function properly
BUT the transmission now comes out of mesh in 4th
gear when coasting. not often but everu 3 miles or so.
did not do it prior to the work on the clutch,
does anyone have an idea.
rocco grillo

you have a tranny problem ,does that mean you wear womens cloths
daren

Rocco. I am not particularly good with transmissions. I did take the tranny rebuild course from John Twist a couple of years ago and he mentioned that the most common cause of jumping out of gear were worn syncros. Something completely independent of the clutch change, but influenced by it. If the clutch was not holding firmly--i.e. slipping a little, the worn sync rings may not of shown up.

However, since the engine and tranny have been out of the car, and the gear shift lever removed, all replaced and, perhaps a new shifter gaiter installed, your might, engine off, shift into 4th gear and measure from the front of the knob to the dash. Then, remove the hold down ring for the gaiter, move the gaiter upwards and put the tranny into 4th gear again and re-measure. The second most common problem when the tranny jumps out of gear is something causing it to fail to go fully into gear.

You might look up John's website, University Motors Ltd. and give him a call during his tech hour and discuss this problem with him.

Les
Les Bengtson

Rocco This is usually an alignment problem and if it did not slip out of gear before the things to look at are:
Loose clutch housing bolts, a slipped or missing dowel pin (engine to clutch housing) A warped housing,(through being forced), something jammed between the engine and clutch housing(a wire is common)or the clutch plate centre could be distorted, spigot missing. These are all things I have struck over the years. Start with the easy things first like loose housing etc. Denis
DENIS H

Jumping out of gear on overrun is usually because of endfloat in the gear clusters. The gears move, but the selector doesn't, and it pulls itself out of gear.

I don't see how a clutch change could affect it though.

Does the lever actually jump into neutral, or are you just losing the drive? Loss of drive could be an overdrive fault.
Martin Layton

Sounds like the pilot bush in the crankshaft fell out when it was apart. Another way of saying what Denis said, specifically "spigot missing". It is common that they are loose in the crankshaft. They should be replaced in that case, and should be tight. Without it the gearbox input shaft can flop around which will make it jump out of 4th.
Other worn bearings generally make it jump out of other gears - fourth is the lest likely to jump, even in a junk transmission.
FRM
FR Millmore

It may be easier than everyone has listed. I had a similar problem in a midget I had. I had installed a new rubber boot around the shifter. It was in a bind and caused it to jump out. I refitted it and all was good....otherwise.....everyone else is on the right track.
bcrazy

Similar to bcrazy, my 75 Roadster has a leather/vinyl cover over the rubber boot which I had left tucked down around the pivot area of the shifter instead of allowing it to extend up the lever. Popped out of reverse a lot before I figured out what was happening.

Wayne
Wayne Pearson

This thread was discussed between 03/05/2007 and 04/05/2007

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