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Hi, Here in the UK I have installed a brand new T5-Z spec in my Plus 8 Morgan (240 hp). Everything was Ok and quiet for the first 75 miles. When I took it out the next time as soon as I put it in 5th gear and put 5th under load, this loud whirring/rattling noise came from the transmission - the other four gears are quiet even with the car's sheet metal transmission cover removed.

I also noticed that the shifter also jerks back (1/8" at the top of the 6" lever) quite violently but a few seconds after load is applied and the noise starts. The noise is a loud whirring and sounds like someone gargling - like rotating metal to metal. Oil level is correct and ATF used.

The transmission is now out of the car and all looks ok inside both the case and the tail housing and the two snap rings on both gears are in place.

Any suggestions from transmission experts as to the cause would be most welcome as I cannot see or work out the cause? There may be a delay is response due to the time difference though. Thanks in advance.
 

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A Plus 8 Morgan!

Oh well, a T5z is a T5z...

Only in fifth gear, and everything looks ok.

How much preload is on the main shaft and the countergear shaft?
Was anything modified about the input shaft or input bearing retainer to adapt it to the Morgan?

If there was somehow some excessive endplay on the main shaft and/or the counter shaft, the two fifth gears would push away from each other a bit. Since those teeth are really shallow, they would be more sensitive to any mis-mesh going on and might make noise.
 

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Discussion Starter #3
Thanks for replying. I just spent 6 months installing this gearbox as original Rover gearbox's are not strong enough and are no longer available. Now this happens to a brand new Ford Racing box with no warranty! At least I don't have to remove the engine to access the gearbox anymore.

The steel nose of the input bearing retainer was machined as the bell housing is fitted with a central throughout clutch cylinder - but the shims underneath were not disturbed. There is no detectable end float on either shaft but the large 5th gearwheel assembly has a lot of end float on the shaft before it contacts the snap ring. Of course, once 5th is engaged, all of the parts in the tail housing are locked together.
 

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I know someone that buys new T5Z units and modifies them extensively for use on Jaguars. He says that many of them are inproperly assembled.

Let's focus on the end play on the fifth gear.

I don't know that there is a specification for that end play. I just checked one I have out on the workbench. That fifth gear doesn't have much play, but I will say it might be as much as 0.010 (inches). I didn't measure it, but guessed this visually.

When driving in fifth, I believe the "bias" of the teeth will force that gear against the rear bearing of the countergear. What is more important, and would affect that mesh would be the endplay of the countergear. Again, the countergear bearings as well as the main shaft bearings are CONE shaped, and any end play will result in lateral movement of the shafts. Can you check the end play of the countergear shaft? You said that the main shaft did not have any end play.
 

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Discussion Starter #5
Thanks again for your reply and for your PM, which I will follow up on. Unfortunately, due to other commitments, I cannot carry out any further work on the box for at least a couple of weeks. Thanks again.
 
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