GKN Diff top up

[poorpeet]

I have done a search but can't find much info. I understand that the filler is hard to reach so any tips there will help but I also need to know how to drain it & what level do you fill it up to.
Its a bit leaky as well which I am told is common on the GKN. can the rear cover be removed & resealed with the diff in place? Access took a real pig!

[spend]

You cant get the finned cover off (its hard enough to get the diff out with the finned version!).

Filler is halfway up diff, drain is at bottom - get at both from drivers side. Just fill to level of filler plug ( I tilt the car to get a bit extra in - only leaks I get are through the vent on top) Diff oil is thick and you just need to take time to fill it, I rig a funnel and long tube so I can do something else whilst it slowly drians down.

Dave

[Ribol]

spend said:

I tilt the car to get a bit extra in - only leaks I get are through the vent on top

Do you not think the two could be connected?

[f1fx]

I have changed My oil recently After it being to fforest garages nr Swansea. after all the work that was done on the car by this TVR "specialist" the only job i thought he had done correct was my diff oil .. Until after 20 mins of driving.. the plates inside would chatter very bad .. And even pulling away. I have had to correct every single job he done on the car myself. And he had it for 50 DAYS.
So i had a feeling that he had put the wrong oil in my diff, I wanted to change it . So i called the place that rebuilt my diff. Dilwin at Promax, top bloke . he suggested castrol B373 LSD racing oil in the diff. and even come to meet me at the services on the motorway with the oil on a Sunday ! ever since the diff has stopped chatting
Anyway.. I drained the oil by . jacking the car up with the OS rear wheel off drained the oil easy ! Removing the plug off the bottom of the GKN diff " the one with fins" and then put the drain plug back in when your happy with what has come out. now for the filling up !!!
I got a nice long extension bar bout 13 inches long on half inch drive socket" it will come half way down the swing arms" and fits just right in the plug. The ratchet will then be easy to turn. Removing the plug.
I then took a funnel and a bit of hose pipe pushed it it to the filler hole, hung the funnel up , and lowerd the car to the correct height. as if the car was sat on all 4 wheels, this is important as you DO NOT want to OVER FILL, i then poured the castrol B373 diff oil "Treacle" in the funnel, 30 + mins and 1.5 ltrs later, it was full. take the filler pipe out . And leave it for 15 -30 mins for the excess to come out . Make sure you do this because if you over fill you can pop your oil seals. when it has stopped coming out . With the car level, put the fill nut back in. and jack back up wheel back on.. And done!
This Castrol B373 oil is thick! And may stop the severity of your leak.

And the last bit of advice NEVER EVER USE fforest garages.

Use Dilwin Promax 01554 784 070. Knows his stuff..

Edited by f1fx on Thursday 18th October 08:52

[poorpeet]

Thanks Matt, Great reply. 1.5 litres required then. It will be interesting to see how much comes out.
The problems you have had with the garage are one of the reasons I like to do as much work on the car as I can myself. Plus I enjoy tinkering & you get to know your car and it's foibles better.
Cheers
Pete

[spend]

Ribol said:

spend said:

I tilt the car to get a bit extra in - only leaks I get are through the vent on top

Do you not think the two could be connected?

If the GKN doesn't blow a bit out of the top - you must be driving like a giggling girl

If you under fill it is easy to kill the bearings so I just make sure I err on the high-side. These diffs are reputed to be susceptible to failure if towed any distance with the nose up.

Do check the level afterwards just to be sure. I suspect I may have killed my diff by not completely filling (within 2 miles) - but having it rebuilt was a good move overall TBH.

Dave

[Ribol]

spend said:

If the GKN doesn't blow a bit out of the top - you must be driving like a giggling girl

Or it has been overfilled by someone who is doing it wrong

spend said:

If you under fill it is easy to kill the bearings

That bit you got right

spend said:

I suspect I may have killed my diff by not completely filling (within 2 miles)

[f1fx]

poorpeet said:

Thanks Matt, Great reply. 1.5 litres required then. It will be interesting to see how much comes out.
The problems you have had with the garage are one of the reasons I like to do as much work on the car as I can myself. Plus I enjoy tinkering & you get to know your car and it's foibles better.
Cheers
Pete

Get 2 ltrs .. and fill till it starts coming out .. then leave it for 15 -30 mins to level out .. maybe give the wheel a turn to move the oil around the diff in the housing and get rid of any air pockets.

[spend]

Ribol said:

spend said:

If the GKN doesn't blow a bit out of the top - you must be driving like a giggling girl

Or it has been overfilled by someone who is doing it wrong

spend said:

If you under fill it is easy to kill the bearings

That bit you got right

spend said:

I suspect I may have killed my diff by not completely filling (within 2 miles)

Your petty jibes, and belief that sticking to the exact level represented by a hole in a casting just make me laugh BTW.

Dave

[Ribol]

spend said:

Your petty jibes, and belief that sticking to the exact level represented by a hole in a casting just make me laugh BTW.

I was being polite, what I really wanted to say is that you were talking rubbish.

It may surprise you to learn that the hole is not just stuck anywhere on the casting, I will leave you to work out why they put it where it is