Triumph Repair: 1977 Spitfire Speedometer Cable, speedometer gear, drive flange

Question
QUESTION: Speedometer quit so I pulled the cables.  The lower one attached to the transmission will not pull away from the pinion housing.  I assume it maybe rusted in or just stuck.  I don't want to force it and the manuals kind of indicate it should just slip out of the housing just like the upper so it can be lubricated or serviced.  I don't know what to do now.  Can you give me any advise?
Thanks very much.

ANSWER: Hi Gary,
If it is stuck hard, it is probably wrung off and pieces waded up inside. So you may have to force it.
Howard

---------- FOLLOW-UP ----------

QUESTION: Howard,
Thanks.  Got it loose and now I have found that the plastic gear inside the rear transmission extension is bad.  I can get a replacement, but I am wondering if I have to take the whole transmission out just to replace the speedometer gear or can I carefully raise it a bit, remove the drive flange, slide out the shaft and replace the gear.  My three manuals are a bit contradictory on this issue.  One says to remove the engine and transmission, one says to remove it from the bell housing back and the other says to access it through the top cover and through the rear of the transmission.  I am totally confused.  I live in Montana and there are not a lot of triumph people around.
Thanks again
Gary

ANSWER: Which gear are you talking about? There is a worm gear on the transmission main shaft and there is the small gear on the small shaft that the cable fits into. Which one is damaged?
Howard

---------- FOLLOW-UP ----------

QUESTION: Howard,
Thanks for the quick response.  The damaged gear is gear on the main shaft.  The gear that attaches to the cable is in really good shape.  The one on the main shaft seems to be really worn down.
Gary.
PS.  Just for curiosity's sake, where are you located?  I won't be offended if you would rather not say.
Thanks again.

Answer
I don't remember that gear being plastic but it has been a long time since I was into a 77 Spitfire gear box. However, if that is the gear that is damaged then the gearbox tailshaft housing must be removed to get that gear off of the shaft. I have never tried to remove a tailshaft housing with the trans still in the car so I can't say for sure it can't be done.

I am in middle TN. Back in the woods but I have an Indian guide to show me the way home each time I go to town.

Howard