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Wedge Mystery TR7 Rattle

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MichaelF

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81 TR7 FI - 5 speed.

Looking for good ideas to check out this noise.

At 3500 - 4000 RPM I hear a rattle. This is definitely in the drive system somewhere and not a body noise. This happens

- in all gears
- only under power not deceleration or holding steady
- not when out of gear
- fades out by 4500 or is covered by engine noise

It's exactly the kind of sound that a badly sticking valve makes - metallic tapping - but since I don't hear it in the engine compartment, I assume it is not that.

It's not terribly loud in the car but is noticeable. At highways speeds I barely hear it.

Poking my fingers around the shift linkage makes a few lighter rattles go away but not the one I'm sleuthing. I do notice that the power on/off that can make the sound disappear co-incides with movement in transmission position I can feel. I'm not sure that is related but mention it anyway.

Transmission & clutch otherwise fine. PO had broken the speedo so I estimate 60-70K miles on the car. Compression good.

Any suggestions on what to poke, prod or twist to locate the sound -- much appreciated.
 
Michael,

I've got a 79 TR7 that make a sound close to what you describe. I replaced the rear axle bushings and it went away, (upper & lower), another area to look at would be your prop shaft. Remove it, and move each joint through its full range of motion, look for slop, or binding.
 
Michael, is the rattle noice accompanied by a vibration? If so, do you feel the vibration in the steering wheel, in your seat, or both?

Hopefully, it's just a rattle which is par for the Triumph course, I think!
 
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by steve99:
Michael,

another area to look at would be your prop shaft. Remove it, and move each joint through its full range of motion, look for slop, or binding.<hr></blockquote>
Think I would start with the prop shaft too. The CV joints are great and should be good for ever except the dirt seals tear up and then the joints go to heck quickly. Good Luck and let us know what you find out.
 
My bet is the rear mounts that live under the shifter have dissolved. The lite oil in a 7/8 tranny leaks past the O rings on the shifting rods and onto the tranny mount. My solution is to put the new mounts into a ziplock bag, poke the studs through the plastic and install.It might look a little strange but it works well.
MD(mad dog)
 
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by MDCanaday:
My bet is the rear mounts that live under the shifter have dissolved. The lite oil in a 7/8 tranny leaks past the O rings on the shifting rods and onto the tranny mount. My solution is to put the new mounts into a ziplock bag, poke the studs through the plastic and install.It might look a little strange but it works well.
MD(mad dog)<hr></blockquote>
Am assuming you mean the rubber grommets (4) under there. Mine were shot when I rebuilt last year and replaced with new. I'm guessing they may be gone again. Will take to heart your suggestion about the zip-lock bags(would a regular baggie work?) They would probably enhance the overall appearance of my undercarriage. Thanks for the tip
 
Thanks -- these are very good suggestions.

All bushing were replaced not long ago and this did not change the rattle. There's no vibration associated with it I can feel.

The sound seems much more 'inside the car' than a prop shaft but I think it's wise to look at it.

>> rear mounts that live under the shifter have dissolved

This 'sounds' right and makes sense of the sound coming and going 'on power/off power' as the transmission shifts a bit. I can feel it move slightly.

Is this a from the top or 'remove transmission' type of check ?
 
It's really easy to check your universal joints. Just (safely) get under the car, with the transmission in gear, grab the propshaft and twist it vigorously as if you were trying to make it rotate.

If there's play in it, more than a fraction of an inch, replace both universal joints.

Bad universal joints are common in older cars, and can be very dangerous if not fixed.

Let us know how it goes, and good luck!
 
Michael,

The task of replacing the shifter assembly bushings on your trans of course is very simple to do if you have the unit removed from the car. However, if you were to remove the console and the shifter boot to gain acces from the top, you may be able to do this. I dont know, but you may have to drop the prop shaft and the cross member to allow the trans to "sag" enough to make room. PLEASE BE CAREFULL TO SUPPORT EVERYTHING WELL IF YOU DO THIS.
 
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