Jump to content

Leaking speedo oil seals

Recommended Posts

All. Has anyone else experienced a leaking oil seal from the overdrive to the speedo cable? 

Ive just had my dials restored by speedy cables who advised me that the speedo was contaminated with gear oil and they suspected a leaking oil seal at the gearbox (d type overdrive for me )

i looked this weekend and unfortunately it looks like they might be correct. I’ve removed the angle drive but the main unit is stuck. I think I need to also remove exhaust pipe to access the locking bolt at the end of the overdrive - is this correct?

when I looked at the Canley web site I think the oil seals are not serviceable unless I have the wrong parts. There is one o ring but that doesn’t appear to be near the rotating shaft. Also the main unit ( the bit that actually goes into the overdrive) has a couple of flats that suggest it should be screwed in but isn’t tight and actually rocks back and forth a few degrees. 

Overall not encouraging. 

Has anyone else explored.? Do I bother? Can you get seals?  How do I remove with gearbox still in car but cover removed.  I’m sure someone out there has beaten me to this problem


thanks in advance


Link to comment
Share on other sites

There are two seals on the drive   the 0 ring seals the hsg. To the case ,

Yes retained by the short spigot bolt in the rear hsg.

Yes it just pulls out

The end of the body has the screwed in speedo cable  adaptor ,  hence the two flats this is screwed in   remove and under is a small oil seal

If not on normal suppliers  try od spares or overdrive repairs for spares   both very helpfull

Should be able to do this On car,   maybe undo the mount and lift the rear of the box  if access is tight 

Dry thr speedo inner and lubticate with graphite powder or non transitional grease

Always fit a 7/16" washer insde the angle drive , to space it away from the od drive


Link to comment
Share on other sites

speedo seal is available 50607s on here https://rimmerbros.com/Item--i-GRID005716

you need to remove the bolt that holds the unit in and then pull it out, drain oil first of course. The bearing should just unscrew to replace the seal however on some later models they are pinned which is a right PITA to drill out. The whole bearing assembly and gear drive if needed are available from the specialist Pete mentioned.

Link to comment
Share on other sites

Ok thanks. Where is the breather please. I’ve looked but haven’t found. Also. I’ve looked on the rimmer site for the d type overdrive which is on the spitfire site not GT6 one and yes they have seals listed but no image to show where fitted. Suggestions pls. Kevin

Link to comment
Share on other sites

The breather is a cylindrical 'bolt' on the top of the overdrive main case. The seal is fitted by undoing the retaining bolt on the rear of the OD case and pulling the speedo unit out. There is a gear which then pulls out of the brass bearing. The bearing is made in 2 halves which just screw together though may have a tiny pin which needs drilling out. The seal sits in the middle. There is also an o ring around the bearing. If your not sure just phone one of the OD specialists, they will have a complete new bearing unit, are very helpful and in my experience if it has a pin in the £30 or so is well worth it.

Link to comment
Share on other sites

A D type overdrive is a d type overdrive so it doesn't matter what car it is listed for (well they may have different output flanges and the number of teeth on the speedo drive varies but basically identical. I would deal with the overdrive guys mentioned not the normal suppliers as they have the knowledge and parts.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...