Speedo Drive Pinion

[DNK]

When you pull out that bugger does the threaded part come too? I need to clean the threads for the new cable. Any suggestions for pulling on it??


Well looking at 37-25-13 the drawing looks like it comes out. Now the big question. What is the best method to pull it out?

 

[Norton47]

Don
You mean at the tranny?

 

[DNK]

Yep

 

[Tinster]

Don-

I recently replaced DPO Pedro's broken speedo cable.
Pretty straight forward. Unscrew one end from behind
the speedo; put the front end on jack stands and unscrew
the other end from the tranny under the car.

It was easy, even I could do it..... in less than a day!!

dale

 

[DNK]

The cables no problem Dale. The trans tunnel is off. I want to freshen up the threads on the male side. I need to pull out the pinion.

 

[Norton47]

Don
I pulled out my old trans and took a look and checked the Bentleys. There is a bolt/pin that threads down to engage a groove on the speedo pinion. Pull that and the pinion is free to pull out.
Now there's the rub, it looks like there is an o-ring that will cause drag and also the fit of the pinion.
I see three choices, 2 prying devices to attempt to gently prise it out, being careful of the threads, find a nut that will thread on (difficult because of size perhaps and the fact that your threads may not be in top form) and you can pry against the nut. Or take off the tail shaft housing.
You might try wrapping the threads with several layers of duct tape and using a pliers. Ohh that is so savage.

 

[DNK]

I used the old cable nut that had 20 plus years of plier marks on it and used it to pry it most of the way out to check the thread size. I think it is 3/4 27 anybody ok that or have a different opinion?

 

[TR3driver]

It's important to remove the pinion BEFORE removing the tailshaft housing, as otherwise it's apt to break when it hits the part of the shaft with no teeth.

I found the "nut" from an old speedo cable (tach cable from a TR3 will work as well) and used that to protect the threads while prying with a pair of small pry bars. In addition to the O-ring & fit; mine seemed to be glued in by old, dried gear oil.

There are different configurations and I don't have them all straight, but ISTR those threads are brass on a TR3, so rather fragile. Here's Nelson doing it with one prybar.

 

[DNK]

That's what I did. Moss still shows the part available. Is there a link to Nelsons deal?

 

[DNK]

Possibly
0.6875
(11/16) inch 26 Tpi 0.0385 0.6465 ins 0.6496 inch
16.5 mm

Naw, rechecked,pretty sure it's 3/4 27

Dang- there is a 3/4 26 pitch
now I don't know.

 

[DNK]

Well I got it out cleaned it up and tried to clean the threads as much as possible (they are 3/4 26. Try to find that die). While it was out I screw the new cable on to it so I could get on good and tight. Is the hole in the gear suppose to be round to except the center of the cable. Boy, I hope so . Put a little lube on it jockeyed it into position and tightened it down. It better work.

 

[TR3driver]

I do seem to recall that the opening is round; but the inside of the hole had better be square to engage the flats on the cable or it's not gonna work.

 

[DNK]

I did check it out by spinning the gear and the cable was spinning at the other end. Looks like it is in 1 piece then too.

 

[DNK]

So,I jerked out the old speedo cable ,have it attached to the pinion drive have it threaded thru the frame member support by the trans. Now the real question. Is it suppose to be held to the frame anywhere with clips?

 

[Brosky]

Don,

Page 193 of the TRF Blue book shows only the cable, with no attaching clips or hardware.