Gear box oil change

[Quincey]

Howdy all.
My gear box was kinda noisy so I changed the oil last weekend. All gears were easy enough to find prior to changing the oil, now 1st is damn near impossible and 2nd is almost as difficult. Abount 500ml of thick, gelatinous black sludge came out and 3.5 litres of fresh gear oil went in, now I got this problem.
Any thoughts, as always, would be appreciated.

 

[Trikky2]

Howdy all.
My gear box was kinda noisy so I changed the oil last weekend. All gears were easy enough to find prior to changing the oil, now 1st is damn near impossible and 2nd is almost as difficult. Abount 500ml of thick, gelatinous black sludge came out and 3.5 litres of fresh gear oil went in, now I got this problem.
Any thoughts, as always, would be appreciated.

Only 500 ml came out?? Half a liter... :shock: Where did it go?

What oil did you put in the gearbox?

 

[Quincey]

Yes, only half a litre. I suppose it slowly leaked out over the last 40 years. There are no tell tale signs of any leaks at all on my driveway so I am at a loss. I put SAE 90 Hypoid as per the Haynes manual. I thought I might get some immediate results ie, a quieter box but instead I have this gear change issue. I filled the box using a length of hose and a foot pump. Don't know if it's a coincidence but had no trouble with any gears prior (other than 4th gear being a little noisy) this was the original reason it was suggested I change the oil.

 

[Trikky2]

Well I have to admit I am surprised you have a gearbox left.

When you say the gears are difficult do you mean they are hard to get it to go into gear but ok when stationary engine off?

If this is the case then your answer lays in the oil - the recommendation was changed to ep80 after the haynes manual was published. Ep90 causes the synchro rings to baulk when the oil is cold. Change it for some ep80 or if you cant get ep80 then you can used the ep80/90 that is widely available.

 

[Quincey]

Funny you mention it but yes, seems no problem when cold. It's after 10 minutes or so that the problem arises. When I first take off, 1st and 2nd are fine.
Thanks for your response. I'll change the oil as per your suggestion and see what happens.