Sluggish Overdrive

[FatJon]

Good Morning Everyone,

 

I noticed at the weekend that my OD has become very slow (up to 30 seconds) to engage and disengage. This came on very suddenly, it was fine last week.

Apart from the slowness it seems to work correctly with no noises or other problems.

Is there a standard fix for this problem?

[RogerH]

It could be low oil level

or

Dodgy oil - what oil is in there.  It could frothing/aerating.   I use Penrite GB40 and appears to work well.

or

mechanical issue

or

.......................................

 

Roger

 

[RobH]

When was the OD filter last cleaned?

[FatJon]

Thanks,

Will check the oil level. Is the OD oil shared with the gearbox?

Where do I find the OD oil filter, I have never cleaned it so it was either a little over a thousand miles ago when it was supplied "fully serviced" or quite possibly never.

 

 

[RogerH]

The GB & OD share the oil.

Underneath the OD there is a large Brass  'eared'  nut. Drain the oil using the square GB oil drain first. Then undo the Brass nut. It can be messy.

The Brass nut and filter should drop away together. Watch out for the magnetic particle rings.

 

Roger

[RobH]

 

5 minutes ago, FatJon said:

Where do I find the OD oil filter

Its the big brass plug on the bottom of the overdrive (assuming A type).  This old thread explains.  If it's only done that low mileage it should be OK but who knows? Yes the oil is shared with the gearbox:

 

[FatJon]

Thanks all. I will get it up on the ramp when my son gets his MX5 off it. Getting heartily sick of seeing the bottom of that Mazda. 

[matt george]

As said, checking the oil is your first port of call. I had a problem with intermittent overdrive engagement on my '6 and it turned out to be a sticky/weak solenoid, which I sorted by replacing said solenoid. Just some more food for thought.

Matt

[Rob Salisbury]

Or maybe just an adjustment of the solenoid/actuating lever is all that's required.

Cheers Rob

[BlueTR3A-5EKT]

On 9/1/2022 at 10:11 AM, FatJon said:

Good Morning Everyone,

 

I noticed at the weekend that my OD has become very slow (up to 30 seconds) to engage and disengage. This came on very suddenly, it was fine last week.

Apart from the slowness it seems to work correctly with no noises or other problems.

Is there a standard fix for this problem?

Which type of overdrive?

[FatJon]

No idea, it's a 1970 CP if that gives any clues. Unfortunately my car lift did't become free until Sunday evening so I've still not had chance to get a good look at it.

 

[rcreweread]

Well if it's original, it should be an A type  - does it work in 2nd gear? If its an A type , it should like the one in the 1st photo - if it's a Jtype, like the one in the 2nd photos

Cheers Rich

[FatJon]

Thanks Rich, will get under there and have a look.

 

[mrehke]

FJ...

If it is a Type A Laycock de Normanville Overdrive fitted to yours it will engage in 2nd, 3rd and 4th gears - with the later J Type it only engages in 3rd and 4th.

To remove the castellated brass drain plug Overdrive Repair Services sell a very good special spanner that exactly fits the castellations, and comes recommended...see https://www.overdrive-repairs.co.uk/buy-spares.php?cat=A Type Spare Parts List - part ORSSPN.  They also sell the mesh strainer basket oil filter ( 509884/OVD175) the castellated drain plug if yours is buggered (part 521814) and the magnetic washers (513205/OVD172) that sit inside the drain plug...

Enjoy!

Mark