gearbox/overdrive oil leak

[Dazzer]

Ok I'm presuming the gearbox oil covering the underneath of the body on our TR4 is leaking from the rear of the overdrive output shaft and I wondered if anyone had replaced the seal in situ?

 

Alternatively, could it be that they are prone to this and I'd just be wasting my time.

 

Is it easier to just keep topping up?

 

We'll be departing on a 4000 mile round trip in the summer and didnt want to be constantly thinking about gearbox oil on the journey.

 

Thanks guys

 

Darren

[Smokey]

It would be a good idea to check out where it's leaking. Dry it off, drive it for a while, and then check underneath. Has it been leaking since it was installed or did it just start? A major cause is a warped adaptor plate between the transmission and the overdrive - that's what caused the oil puddle under the car in my case, and unfortunately the only cure is to replace the adaptor plate. That can be checked by drying off the overdrive and letting it sit, because the plate will leak when the car is stationary.There is a later reinforced version of the plate that is less prone to warping.

 

Check out the Buckeye Triumphs site - they have some excellent technical articles on the foibles of the overdrive, although it's not for the faint of heart. Afraid I can't help on the question of whether the seal can be replaced in situ, but the first order of business should be to confirm exactly where it's leaking from. Ahh, British cars - why add a couple of gears to the transmission when you can play with 500 psi hydraulics, electrical realays, switches and solenoids, springs, clutches, Boolean algebra with detent switches, and engine oil in a transmission?

[Ade-TR4]

You definately need to find where the oil is coming from.

 

As Dazzer says, dry it of and go for a short spin, or even just let it stand.

 

If the oil is coming from further up the drivetrain/ engine, the air pushes it rearward as you drive.

 

I thought I had a leaking G/box, only to finally trace it to the rear of the rocker cover where an old gasket had split! (thankfully a very easy fix in comparison!)

 

Good luck

 

Adey

 

Remember: when a TR stops leaking oil; it's run out

[Dazzer]

Thanks Smokey & Adey

 

I'll check out the buckeye site and yes it is a complex arrangement when you now look at six speed boxes.

 

I guess its going to be a complete clean off and test run then... Quite a new gearbox & O/D uprated unit as well... less than 5000 miles and the synchros on 2nd and 4th are starting to fail. The baulk rings must be made of pasticene.

 

Next time I'll pay top money for something that actually lasts.

 

Cheers

 

Darren

[ChrisR-4A]

Hi Darren, my 4A had a leak from the rear seal and I put up with it for 2 years, checking the oil level before a long trip, and finally fixed it when the box was out to fit a new clutch.

 

To facillitate easy top ups it's worth cutting a hole, (about2"dia) in the side of the trans trim cover, so top up can be done from inside the car by removing a suitable bung. Takes about 5mins to check and all you need is level ground. To undo the level plug I use a 3" long 3/8 extension turned round with the square female fitting over the square plug which may need slightly fileing down to fit. I then welded a socket to the other end of the extension to drive it.

Make the plug a close fit and it won't drop off as you remove it into the car footwell.

 

Chris

[Dazzer]

Hi Chris

 

Thanks for the tip. I like it.

 

I'll definitely do as you say and can check it half way through the trip.

 

Many thanks

 

Darren

[Grahamgl]

Hi Darren

If, when you say the output shaft seal, you mean part number GHS179, as shown in the Moss catalogue, I have been told that it is easy to replace it without removing the gearbox and overdrive. You have to remove the gearbox cover from inside the car with all that entails, remove the four bolts holding the propshaft flange to the flange on the overdrive, undo the castellated nut that holds the flange on the overdrive shaft, remove flange and nut and what you then see is the back of the oil seal. Prise it out and carefully fit a replacement seal then re-assemble the removed parts. I was also advised to jack up the back of the car and put it on axle stands so that the oil in the overdrive/gearbox runs away from the seal area and thus should not leak out when you remove the seal.

Graham

Edited March 13, 2009 by Grahamgl

[Dazzer]

Hi Graham

 

Thanks for the info, sounds very doable.

 

Into the garage once again it is.

 

Cheers

 

Darren

[Smokey]

Hi Dazzer, were you able to replace the rear seal with the tranny in place? I may be facing the same task, and I've been told it's possible but very difficult.

[Trperson]

Definitely need to replace mine, have the seal. Need a special tool to pull the old seal?

[dingle]

It won't fix the leak, but drilling a hole in the tunnel cover adjacent to the trans. fill plug will make checking and refilling the trans. much easier. The hole can be filled with a rubber plug, like the one in the floor board for the jack.

Berry

Whoops-Looks like I duplicated a previous post. You can also replace the square head plug with one having a hex or socket head.

Edited September 9, 2017 by dingle

[james christie]

It is certainly possible to do this on a sidescreen car once you have removed the transmission cover but I don't know my way around these modern things with windows. You'll need a puller with short legs to get the rear flange off and then one of those 'parrot beak' devices to get the old seal out without damaging anything else. Clean up the faces where the seal fits and have a good look for wear on the rear flange. If necessary consider a 'speedi sleeve' .

It's easy for me to tell you this as I've got my gearbox on the bench at the moment

 

James