Any overdrive gurus?

[Doug Paterson]

Hi

Got a bit of a problem with my OD - its a J-type Laycock unit in a Spit 1500.

At the weekend, all was well, however of late I have been finding that it takes a few miles for the overdrive to start working (e.g. after the car has been parked for a week or so).

Anyhow - the latest issue is that on the way back to base at the weekend the following started to happen.

1.  Overdrive engaged - works absolutely fine both accelerating and on the overrun (decelerating).
2.  Overdrive disengaged - works fine when accelerating.  However when taking foot off the gas I get a few seconds where it feels like it is freewheeling and then it feels like its reverting to overdrive-engaged.

Some troubleshooting notes hint that this may be due to a blocked pressure relief valve/blocked pressure filter.  Have drained the oil out and replaced the filter & have fingers crossed that when I re-fill with fresh oil and start her up things will function normally.  

Anything else worth trying before my thoughts start drifting towards a recon unit?

Cheers for any thoughts.

Doug.

[Slimboyfat]

Temperature sensitive J type problems are usually down to dodgy solenoids. It's either been knocked, or more likely the shuttle O rings are cream crackered.
Slipping J types are common on 78 onwards Spit 1500's, GKN changed the UDC spec and they tend to wear more rapidly than earlier cars and cause slippage (usually under acceleration though).

http://www.canleyclassics.com/infodatabase.asp?article=overdrivesjtype

[Doug Paterson]

Thanks Slim,

Well looks like it may have been a relief valve issue - refilled with oil today after changing the high pressure filter and after getting it off the jacks took it for a spin - seems to be working again and in fact its much more responsive than its been for ages.

Fingers crossed it stays that way.

[Deleted User]

Wiring diagram attached.
could be a clogged oil filter, or crappy oil? Rob

[Jonny-Jimbo]

I've got a problem with mine too.

Initially it engages fine, and really kicks in hard, as if it's trying to throw you off the road!

Recently it's been slow to come in and some times get's stuck in, usually the car starts getting back up to temperature. It stays in throughout all gears, including reverse. As soon as this happens I cut the engine off and push it as I've heard real horror stories about overdrives being engaged in 1st and Reverse! As it is mines an uprated unit that runs in 2nd, 3rd and 4th.

I've changed the oil and all seemed well at first, but it seems to have gone back to being sticky in less than a day, so do we recon that's a solenoid problem too? Having read the Canley's website I think that it is a solenoid, but unfortunately I don't seem to have the spare cash right now for a solenoid. Bugger.

[Doug Paterson]

bobyspit wrote:

Wiring diagram attached.
could be a clogged oil filter, or crappy oil? Rob

Thanks - think it was a clogged oil filter - all seems better than ever now.

[Doug Paterson]

Jonny_Jimbo wrote:

I've got a problem with mine too.

Initially it engages fine, and really kicks in hard, as if it's trying to throw you off the road!

Recently it's been slow to come in and some times get's stuck in, usually the car starts getting back up to temperature. It stays in throughout all gears, including reverse. As soon as this happens I cut the engine off and push it as I've heard real horror stories about overdrives being engaged in 1st and Reverse! As it is mines an uprated unit that runs in 2nd, 3rd and 4th.

I've changed the oil and all seemed well at first, but it seems to have gone back to being sticky in less than a day, so do we recon that's a solenoid problem too? Having read the Canley's website I think that it is a solenoid, but unfortunately I don't seem to have the spare cash right now for a solenoid. Bugger.

Sorry didn't realise that Bobby was replying to your post.  I think its worth changing the high pressure filter (much cheaper) or even taking the old one out and giving it a good clean.   Mine had behaved like yours in the past .... rather than shutting the engine off I tended to keep driving but taking it easy until it disengaged.

Worth a try.

[Pete Lewis]

Had a J type in a Hunter that got slow and solenoid gunged up with rust and whatever
worth just take it off and have a look at the core condition  Peter

[Jonny-Jimbo]

The overdrive was newly built around 5 years ago, and has previously only been used as a race gearbox in a TSSC / TR race series car, so I doubt it's rusty. I'll try and get at the oil filter if I can, not too sure about taking overdrives apart... whats the worst that can happen...

[Clive]

JJ, take the solenoid out and inspect it. It may be worth getting new o-rings too while you are at it, and check it moves freely when connected up.
The filter IIRC is under a plate on the bottom of the OD unit. And I wonder if it is possible to flush a gearbox/od. Somebody suggested diesel to me, but I was never brave enough. May work though, wouldn't want to leave it in to drive it, maybe wheels off the ground forr 10 mins with od engaged to help clear any gunk? be no pressure on the gears then?

Clive

[Pete Lewis]

taking an overdrive apart is OK but read a proper manual and backwards twice before you start, and question each move.

and the Hunter was only 2 years old and had half the titanic   inside the sol..   Peter

[Deleted User]

I found people dont bother changing the gearbox oil when they should!
I would do it every other service!
My overdrive has worked like clockwork!
Rob

[Doug Paterson]

Another question .... I've removed the tunnel cover and got to the overdrive which is still playing up (on the overrun when NOT IN OVERDRIVE).... before condemning it I've taken a look at the operation of the solenoid.  Its working but it appears to move very little - around 2 millimetres movement between off and on.

How much movement should I be seeing when operating the solenoid when removed from the car?

Cheers,

Doug.

[Deleted User]

Not sure? Have you tried the solenoid with a fresh 12 Volt? and checked the earth on the solenoid? On doing this you can rule out a iffy switch or earth! I would try everything before changing the solenoid!
Rob

[Doug Paterson]

bobyspit wrote:

Not sure? Have you tried the solenoid with a fresh 12 Volt? and checked the earth on the solenoid? On doing this you can rule out a iffy switch or earth! I would try everything before changing the solenoid!
Rob

Yeah - its getting a full 12Volts at the solenoid.  My problem has been with OD not fully disengaging.  It engages just fine & runs well with OD engaged.  On the overrun with overdrive disengaged is where its behaving badly.  Have read of faulty solenoids causing such symptoms.

[Deleted User]

I am not sure about the movement of the solenoid, I will look at mine but this will not be possible until next weekend as I am at work until next Monday!
Rob

[Doug Paterson]

Thanks - don't put yourself out - got a recon one on its way .... for £50 it ain't gonna hurt to try ..... too much.

Saw this from an OD expert on the Volvo forums (one of my best mates is a Volvo fan and many of them used the J-type)....

The solenoid in its OFF position acts as a stopper to keep fluid from an area that creates the pressure build up necessary to move parts internal to the OD and "engage" the "fifth" gear.  When ON the solenoid valve moves only 1/8 to 3/16 of an inch and allows the fluid past.  The seals internal to all this are two very small O-rings.  There can be over time a small amount of leakage past the "end" O-ring and into the electrical area of the solenoid.  If this leakage is great enough the valve cannot return to the OFF position and the OD then becomes self engaging.  There are all sorts of causes for this to occur, age is one and poor electrical contact which causes heat which bakes the O-rings hard being another.

The solenoid has to be removed and shaken to test it.  Yes, that is the test.  It must rattle freely or it is bad.

[Deleted User]

I have found a bit more info on the Solenoid Test and adjustment!
I will copy verbatim.

1. Remove three screws and star washers.
2. Remove cover Plate.
3. Remove Gasket.
4. Move the operating lever until 3/16 in (4.762mm) Setting pin pushed through the hole in the lever aligns with the hole in the casing.
5. With the Solenoid energised screw the adjusting nut until it just contacts the operating lever.
6. Remove the setting pin.
7. De-energise the overdrive.
8. Energise the solenoid.
9. Re-check the alignment of the holes.
10. Check the current consumption is approximately 2 amps.
11. A reading of 20 amps indicates the solenoid plunger is not moving far enough to switch from the solenoid-operating coil to the holding coil of the solenoid, if this is the case the solenoid needs to be re-adjusted (steps 5-9)
12. Continual high current will cause premature solenoid failure.  

Hope this helps!

[mikeyb]

bobyspit wrote:

I have found a bit more info on the Solenoid Test and adjustment!
I will copy verbatim.

1. Remove three screws and star washers.
2. Remove cover Plate.
3. Remove Gasket.
4. Move the operating lever until 3/16 in (4.762mm) Setting pin pushed through the hole in the lever aligns with the hole in the casing.
5. With the Solenoid energised screw the adjusting nut until it just contacts the operating lever.
6. Remove the setting pin.
7. De-energise the overdrive.
8. Energise the solenoid.
9. Re-check the alignment of the holes.
10. Check the current consumption is approximately 2 amps.
11. A reading of 20 amps indicates the solenoid plunger is not moving far enough to switch from the solenoid-operating coil to the holding coil of the solenoid, if this is the case the solenoid needs to be re-adjusted (steps 5-9)
12. Continual high current will cause premature solenoid failure.  

Hope this helps!

I think this is specific to D-Type o/ds?

[Doug Paterson]

Yeah I think your right Mikey - don't think theres any adjustment on the J-type solenoid.

Thanks for looking that out though Rob.

[Deleted User]

Your right! I found it in my Repair opperation manual! I thought spits ran a J type! mine does! or did some work a D type as well?

[Doug Paterson]

Yeah - older spits had D-type.

Well I've received a re-con solenoid this evening and I believe that there is a good chance it may be the solution to the problem (fingers crossed).

The new one passes the rattle test (rattles freely) the old one doesn't rattle at all.

When operated, the new one has a much more positive movement - a solid clunk as it engages.  The old one is virtually silent.

THe other interesting point is that when switched off, the new one's plunger settles further back towards the body of the solenoid than the old one - this adds weight to the theory that the oil pressure isn't subsiding fully when the OD is disengaged leading to it trying to re-engage on the overrun.

I will bung the driver seat back in at the weekend and give it a spin.

D.

[Deleted User]

Right I now have the J type od rebuild and trouble shooting guide/training manual!
I will scan it mon/tue and post on here!
Should help everyone with a j type od.
Rob

[Doug Paterson]

That would be fantastic Rob.

Mine seems to be behaving itself following a bit of a run today.  

[Deleted User]

Great stuff Doug! So it was the solenoid?