bench test gearbox/overdrive

[Mark69]

Evening All

 

I would like to try a find out the condition of my gearbox and overdrive whilst they are out of the car .

 

Having not had the pleasure to drive car , condition unknown

 

Recommendations of anyone who could assess or bench test , local to me in south Wales would be a bonus.

[Superaquarama]

Not an overwhelming response ! I wouldn't think a bench test is practicable other than under workshop conditions with a test rig etc. I have the same issue, but upon taking off the gearbox lid everything seemed hunky dory so I'm going to take a chance on it.

 

I would say the same applies to the o/drive, just check that the solenoid's clunking in and out then maybe hope for the best. Our overdrive's a different matter, though ! Went to do a simple little job - changing the O ring seal on the actuating lever - when a bit of mangled metal came out with the oil ! So maybe change the oil and see how much debris comes out with it on yours too ?

 

Our car is and was a resto project so I've no idea whether the o/d works, but it seems that it may be a good idea to at least look at it before the body goes on.

 

As most of the parts are available, does anyone know if a diy rebuild is a viable proposition (e.g. any special tools etc needed ?), or is it best to bite the bullet and just get an exchange item from Moss, the guys at Rugby, or wherever ? Time is also a factor since the body is, or at least was, going onto the chassis next week and I'm pretty busy work-wise at present.

 

Anthony

Edited November 22, 2013 by Superaquarama

[johnny250]

A bench test is certainly possible, as is a rebuild of gearbox and overdrive, there is good information available online. (i've sold that motor rig now though) was a big help in checking all OK before installation and getting the correct oil pressure etc, .

 

john

 

 

Edited November 23, 2013 by johnny250

[AlanT]

I have done this. Its cheap and easy:

 

http://www.buckeyetriumphs.org/technical/AOD/AOD4/AOD4.htm

 

Here is my set up:

 

http://flickr.com/gp/90670218@N04/Si056P/

[Nick Jones]

I used an electric drill with chuck directly on the input shaft spigot. The 550 watt drill was fairly close to it's limit when the OD engaged, so long term testing would not have gone well for it. However, I was only checking that the OD did engage so it served my purpose.

 

Nick

[AlanT]

Some risk of marking or bending the spigot if you do this.

 

One thing you find out is the amount of oil drag in these boxes when the oil is cold.

The drill method will be harder to do in the winter.

 

A big benefit is the ability to trace and fix oil leaks easily.

[graeme]

Some risk of marking or bending the spigot if you do this.

 

One thing you find out is the amount of oil drag in these boxes when the oil is cold.

The drill method will be harder to do in the winter.

 

A big benefit is the ability to trace and fix oil leaks easily.

 

 

Hi Alan,

 

I used a drill before but not to test the O/D. I have two boxes to overhaul so I will make a test rig.

 

What power electric motor do you use to drive the box?

 

Cheers

 

Graeme

[rogerguzzi]

Hello Graeme

I rebuilt a gearbox for my spitfire out of about 3 gearboxes and 2 J type overdrives so I wanted to test the overdrive pressure as it is not as high as on TR,s(same overdrive) I used a 1/2hp motor and pulley that gave about a 3 to 1 reduction I think?.

 

It all worked fine and you can adjust pressure if necessary and select all gears and test interlock switches if you like with bit of simple wiring.

 

Its no guarantee the gearbox will be quite under load but still better than just putting it in the car to test overdrive function(and easier on the old back)

 

Roger

 

ps if its noisy under load fit a noisy exhaust!!!

Edited November 24, 2013 by rogerguzzi

[AlanT]

I just bought an import motor from eBay.

 

Remember we have 50Hz power not 60 Hz so standard mains motors here do 1425 rpm. And motors here go by HP not Watts as in the USA. Dont know how you do these things.

 

250W, 1/3 HP will do, but only just. A washing-machine motor would do.

 

An important thing is reversibility so you can set the correct direction. No reversing in OD remember.

 

I have a two step pulley so you can start slow and warm up the oil. Starting in high speed will prevent the motor reaching run speed and it will trip out.

 

You need to choose pulleys so as to get about 1500 rpm mainshaft speed.

 

When mounting the tailshaft pulley remember the fixings holes are not on a square pattern. Actually two bolts will do fine.

 

Please remember that belt drives are dangerous. Keep fingers and clothing well clear.

[Mike Collins]

I found out the hard way that motoring the gearbox from the input shaft makes it almost impsssible to remove the overdrive later.

 

Using the output flange to drive leaves the splines unlocked and the overdrive slips off with ease.

 

Mike.