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J Type overdrive harsh shifting


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8 hours ago, Nobbyc said:

My J type is ex saloon car and has a very smooth action in/out with no need to use clutch. The overdrive has minimal sliding  movement between the engagement of the internal and external surfaces of the cone clutch.  If the thrust washer on the shaft was missing or much too thin then the sliding movement would be excessive and cause harsh action. Not sure if the thrust washer is sintered bronze or solid bronze but know that sintered bronze bushes in A Type overdrives are known to break up and disintigrate.

 

 

Hi Nobby.  Thanks for the extra info, it makes a lot of sense in that no one else has been able to give an explanation as to why this harshness exists and it would also explain the concerning amount of fine silver particles shimmering in the oil.  It looks like the box is going to have to be split to find out exactly what the problem is so I've just ordered a service kit and thrust washer from ORS. 

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Well, after having ordered the parts from ORS I came across an advert for a guy not too far from where I live and who has 40 years experience rebuilding English gearboxes and overdrive units.  He is English himself and has had a lot to do with Pete at ORS over the years.  He supplies rebuilt exchange units for around UK 275 pounds so I'm going to send him mine with the gasket kit to repair or exchange, whichever is cheapest.  I've mentioned the possibility of the thrust washer having been left out and he'll let me know what the actual cause of the harshness was.

Will update again in due course.

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  • 2 months later...
8 hours ago, Nobbyc said:

what was the problem with the o/d has it been sorted

Well it"s one hell of a coincidence you should ask that question today!  At the moment I'm feeling pretty disheartened as I test ran the car on  my hoist this afternoon and there was no sign of the OD engaging.  Double checked that the solenoid is operating (have converted to a sedan switched gear lever) and yes it's switching.  Whats worse is that it's leaking oil from several bolts which I was assured it wouldn't.

I plan to throw the seats back in tomorrow without the carpets as I fear I'll be pulling the transmission out again to repair it myself.  Hopefully it works under load.  If not, I'll be asking for my money back!

Gavin

 

15805466528840.jpg

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4 hours ago, KiwiTR6 said:

Well it"s one hell of a coincidence you should ask that question today!  At the moment I'm feeling pretty disheartened as I test ran the car on  my hoist this afternoon and there was no sign of the OD engaging.  Double checked that the solenoid is operating (have converted to a sedan switched gear lever) and yes it's switching.  Whats worse is that it's leaking oil from several bolts which I was assured it wouldn't.

I plan to throw the seats back in tomorrow without the carpets as I fear I'll be pulling the transmission out again to repair it myself.  Hopefully it works under load.  If not, I'll be asking for my money back!

Gavin

 

15805466528840.jpg

Have you filled the gearbox with oil then run it for a while engaging and disengaging the overdrive and then topped up the gear box?

Stuart.

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8 hours ago, stuart said:

Have you filled the gearbox with oil then run it for a while engaging and disengaging the overdrive and then topped up the gear box?

Stuart.

Not quite, filled from top of box with 2L (the prescribed vol for a dry box and OD according to Haynes manual) of GL4  75W80 semi synthetic gear oil and ran on my 2-post several times switching in and out of OD watching for change in rpm, but no change so assumed it's not working.  Did this several times.

Checked wiring circuits several times and confirmed that solenoid is operating which it is.  Perhaps the only uncertainty is that I'm getting 10V not 12V, but there is 12V at the switch which drops to 10.5 at the fuse box.  Not sure what's going on there?

I've checked the oil level this morning and found it's well overfilled.  Will get this right and then put it on the road for the real test.

Gavin 

 

 

Edited by KiwiTR6
Corrected info in post.
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8 hours ago, Mike C said:

Do you have to set a clearance on the solenoid like with the A type.

No, it's a totally different setup to the A-type with the solenoid being direct acting rather than operating a lever mechanism.

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2 hours ago, KiwiTR6 said:

ran on my 2-post several times switching in and out of OD watching for change in rpm, but no change so assumed it's not working.  Did this several times.

With the road wheels off the ground there is no load on the engine so you probably won't see any change in revs as the O/D cuts in and out. You need to look at what the rear wheels are doing.  They should speed up and slow down. 

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On my A type I wired an indicator light direct to the solenoid connection to tell me when I have power to the solenoid. If I engage the OD switch and the revs don't drop then I just look at the indicator to see if the problem is in the wiring upstream of the solenoid -where it is most of the time. 

Neat indicator lights marked "Overdrive" are available from Landrover suppliers.

 

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1 hour ago, Mike C said:

On my A type I wired an indicator light direct to the solenoid connection to tell me when I have power to the solenoid. If I engage the OD switch and the revs don't drop then I just look at the indicator to see if the problem is in the wiring upstream of the solenoid -where it is most of the time. 

Neat indicator lights marked "Overdrive" are available from Landrover suppliers.

 

Thanks Mike, I have run a wire from the solenoid supply wire back to behind the dash for this purpose, but the light will have to wait until I pull the dash out to tidy up the wiring and more some stage in the future.  I have an idiot light on my dash just above the steering column which no one else seems to have - this will become my OD indicator.

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Took the old girl for a drive this afternoon  and the OD is not operating as I'd feared.  My last thought prior to gearbox removal is to replace the non-return valve in the sump of the OD.  I supplied the repairer with a new part ex OSR along with a repair kit but he didn't use  either which was disappointing.  I'll change this next and see what happens.

 

 

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1 hour ago, KiwiTR6 said:

Thanks Mike, I have run a wire from the solenoid supply wire back to behind the dash for this purpose, but the light will have to wait until I pull the dash out to tidy up the wiring and more some stage in the future.  I have an idiot light on my dash just above the steering column which no one else seems to have - this will become my OD indicator.

I mounted the light in the H frame just alongside the radio, makes for a simpler wiring run and I like it out of the direct line of sight while driving- I find the light switching on and off distracting.

Good luck with the NRV- did your repairer give any reason for not using it?

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1 hour ago, Mike C said:

Good luck with the NRV- did your repairer give any reason for not using it?

I didn't meet him face to face, just spoke over the phone.  When I asked him about using Hylomar on the gaskets to ensure it would be oil-tight and test running the unit up on the bench he replied that he'd been rebuilding them for 40 years so he new what he was doing.  I took him at his word.   In hindsight I should have insisted he use the new non-return kit.  I was possibly rushing things a bit I guess.

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Hi Gavin,

regarding the OD idiot light.  I replaced my column switch with a press button so I needed the light.

I fitted a bright LED in the small cowling up by the steering wheel. This shines upwards and is very easy to see as it reflects off the inside of the steering wheel at the 12-o-clock position.

It auto dims for night driving.

 

Roger

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4 hours ago, KiwiTR6 said:

I didn't meet him face to face, just spoke over the phone.  When I asked him about using Hylomar on the gaskets to ensure it would be oil-tight and test running the unit up on the bench he replied that he'd been rebuilding them for 40 years so he new what he was doing.  I took him at his word.   In hindsight I should have insisted he use the new non-return kit.  I was possibly rushing things a bit I guess.

As long as he didn't say there was a problem he knew about with your new NRV.

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What did your man actually find out about the harshness?  He seems to have fixed the harshness in his eyes!

Cant you get him to look at it now as its his work.

Do you have a pressure gauge?

John

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11 hours ago, John L said:

What did your man actually find out about the harshness?  He seems to have fixed the harshness in his eyes!

Cant you get him to look at it now as its his work.

Do you have a pressure gauge?

John

Hi John.

All he could tell me was that the box was generally in good order but that there was an issue with assembly of the spool valve.  Yes I do have a suitable pressure gauge which Ill put to use if I pull the unit out of the car again.

I drained the gearbox overnight after having decanted 500 mls through the level plug which seemed odd considering I'd added what was noted as the correct volume for a dry GB and OD and had run on the hoist for quite a while plus a road test.  Also this morning I removed the OD drain screw and got virtually nothing out of it with the normal volume out of the sump.  

I think I might be onto something at last!  If the NRV is faulty then I'd assume that the pump won't be circulating oil through the OD resulting in (a) the OD not operating and (b) a surplus of oil remaining in the GB.

I'll change the NRV this evening and see what difference that makes!

Gavin

 

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What a disaster!

I replaced the NRV tonight, redid a few fasteners to get rid of some minor leaks, filled the box with oil then ran her up on the hoist and bingo, the OD engaged and disengaged.  Still seemed harsh but with no load on the wheels I figured it was time for a road test which hopefully would produce a softer change.

Topped up the oil, lowered the hoist and backed slowly out of the shed then bang! No drive in any gear including reverse!  I could select all gears normally and I still had normal stroke and pressure on the clutch pedal, but not drive and no horrid noises that I could hear.

Pushed her back into the shed (well the wife did most of the pushing) and  put her back on the hoist (the car that is). Put the gearbox in second, spun the rear wheels and no resistance whatsoever, the driveshaft turning the OD output as one would expect.

Looks like a terminal failure inside the OD so looks like its coming out again.

I probably won't send it back to the same repairer!

 

 

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Sounds a bit like the one way clutch is damaged.  Have you got the isolator switches correctly wired, you shouldn't be able to get overdrive in reverse, that's what breaks the one way clutch.

Oh dear box out again..

John

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8 minutes ago, John L said:

Sounds a bit like the one way clutch is damaged.  Have you got the isolator switches correctly wired, you shouldn't be able to get overdrive in reverse, that's what breaks the one way clutch.

Oh dear box out again..

John

Hi John.

Yes I checked that multiple times before running the car and just now went out to the shed in the dark to check again (you scared me!).  There is only one isolator for the OD and it passes current in 3rd and fourth gears only, 1st, 2nd and reverse are open circuit. 

I'm sure you're correct though as to what has failed.  As much as it galls me I think I'll be making a call to the repairer tomorrow.  The problem is, I now don't have any confidence in his ability. 

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