J Type Overdrive.

Clutch, Gearbox, Overdrive, Propshaft, Differential, Drive Shafts, Hubs.
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tony
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J Type Overdrive.

#1 Post by tony » Tue Mar 27, 2018 3:19 am

Over the last 18 months I had my gearbox and overdrive overhauled by an "expert" who lives a distance from me. Gearbox good but o/d has never worked since. :shock:
Have acquired a manual from Ebay, taken o/d off gearbox and took it apart.
Think I've found the problem, One O ring on the operating piston was in two pieces. Obviously not replaced last time it was apart.
Fitting the bridge pieces that locate the pistons I find that mine are slightly curved. Can anyone tell me if this is correct or are they meant to be flat?
Thanks.
Tony.
1976 2500 TC. converted to S specs.

Lots of bits

1999 BMW Z3.
2006 BMW 325ti.
Hopefully not needing too many bits.




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Alec
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Re: J Type Overdrive.

#2 Post by Alec » Wed Mar 28, 2018 5:57 am

Hello Tony,

they should be flat but I don't think that slight bend will affect the operation of the overdrive.

Alec
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tony
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Posts: 744
Joined: Sun Jun 14, 2009 5:35 am
Location: New Zealand

Re: J Type Overdrive.

#3 Post by tony » Wed Mar 28, 2018 5:46 pm

Thanks Alec,
Both mine were bent, must be hydraulic pressure over the years. Found slivers of O ring on top of the piston. Seems like excessive travel may have pushed the piston out a bit allowing the O ring to exit the bore. Can't see any other reason. Mates got a large press so he's getting a visit this morning. :lol:
Tony.
1976 2500 TC. converted to S specs.

Lots of bits

1999 BMW Z3.
2006 BMW 325ti.
Hopefully not needing too many bits.




.

tony
Senior Member
Senior Member
Posts: 744
Joined: Sun Jun 14, 2009 5:35 am
Location: New Zealand

Re: J Type Overdrive.

#4 Post by tony » Mon Apr 02, 2018 4:52 am

Success :roll: :roll:
Recently had a cortisone injection in my knee which makes it a bit more user friendly. Decided to get beneath the 2500 and attempt the removal of the overdrive which a previous 'expert' had a go at. He did fix the gearbox (new bearings etc) but seemed to fail with the o/d. He did the bearings and clutch etc but didn't appear to touch the hydraulics.
As stated previously I acquired a Vauxhall J type overdrive training manual from Ebay. Stripped the hydraulics and replaced all the O rings. One of the big ones (operating piston) was in two pieces. Thought this was the main problem. This proved correct. Took it for a drive this afternoon and it worked, for the first time in 15 months.
Marginably easier to remove the o/d than the whole gearbox but still a lot of hard to get at bolts and nuts. grrr. First time in 20 odd years I've had anything but electrical problems with Mr Laycock's product. :shock: Overall a Happy Easter.
1976 2500 TC. converted to S specs.

Lots of bits

1999 BMW Z3.
2006 BMW 325ti.
Hopefully not needing too many bits.




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