Gearbox noises

[worzel]

Hi

I know that diagnosing noises from afar is nigh on impossible but I thought it worth a try in case some fellow sufferers have encountered something similar.

In brief- 2 attempts have been made to cure a noise on 3rd gear on a Type 9. The last involved all new bearings, new layshaft and bearings plus a new 3rd gear. I first stripped the box personally but a visual examination didn't point to anything so I passed the buck to a long-time restorer of gearboxes in general (and an early modifier of the T9) who's been rebuilding boxes in Liverpool for 30 odd years. He checked out everything but couldn't identify any problems. Re-fitted the box after replacing 3rd gear- same noise.

That was 3 years ago- took the plunge a few weeks ago and took the box back to him- completely stripped it and replaced all bearings, layshaft and layshaft bearings, all forks, all synchros and sourced a genuine very low miles laygear. Test drove it to9day and problem remains.

Some salient points-

Gearshift is switch-like on all gears, no synchro problems on any gear, no noise in neutral when idling hot or cold. Noise is only present on 3rd and ONLY on drive ie disappears on overrun. Difficult to describe but not a grinding or whining noise- more like a chipped tooth (there aren't any). Noise isn't horrendous but certainly noticeable and becomes louder if changing to 3rd at lowish speed (I'm not talking crawling pace) on a flat road. Box has been in the car for around 13 years and is a modded T9 ex a 2.8 Capri- noise has only been present last few years- but never got any worse despite using the car with the fault present.. Linkage has been moved to reposition lever. Desperation here- is it possible it's not the box internals but somehow linked to the lever position- the plastic saddle clip is fine but I wondered if 3rd lever position is placing the bottom of the lever (or its side face) in such a position that something is "chattering" below the lever.

One last thought (remote possibility) for those familiar with T9 boxes- to lock out 5th and reverse my gearbox uses a spring loaded cam arrangement. This is achieved by creating a short depression about 0.5 inches long in the "D" washer in the main casing (this washer effectively prevents 2 gears being selected together). At each end of this "depression" there is ramp effect. In the lid of the box is a spring loaded plunger which only operates when either reverse or 5th is selected- across the neutral plane the "depression" allows the lever to move without resistance. On engaging 5th the ramp on one end meets the plunger and to obtain 5th you have to overcome spring resistance. Is it possible that in 3rd there is a slight amount of play (possibly only thousandths of an inch) between the ramp part and the tip of the plunger and this is vibrating? Sounds feasible I suppose but why only 3rd affected as if this is in fact the problem I'd have expected 4th to do likewise since the rightwards movement of the lever remains the same for 3rd and 4th.

Help!

John

Any ideas

[worzel]

Hi- again.

Should have added- the cam arrangement on my car is somewhat similar to that on the Alan Voights conversion for locking out reverse (via the screw in plunger in the box lid in their conversion)- has anybody with one of their boxes ever experience a chattering (or similar) noise in 1st or 2nd/

John

[Thomas1968]

Hi John,

I just bought a Lotus Elan+2 with a type 9, 5 speed gear box , and have found that it makes a vibrating noise in 3rd gear. I didn't notice it during the test drive but the guy selling the car was driving it quite hard and the vibrating noise is less noticeable under these conditions. The noise is most noticeable accelerating at a more normal rate. No vibration from any of the other gears and none from 3rd gear when coasting.

All sounds very similar to your experience and I was wondering if you ever managed to resolve the problem?

Thanks

Tom