Changing the diff.

[Roy Gillett]

I have a replacement diff I want to fit to my +2. Reading the WOrkshop Manual it looks a very straight-forward job. Can anyone talk me through any problems / pitfalls or point me to a string on this site that will help me?

Thanks

Roy

[types26/36]

It is quite stright forward, just follow the manual.The only probs you might encounter are if you have the diff brace fitted, you must remove it befor taking out the diff (although some people have said it can be removed with the diff) ..................not for me!
An other prob is if the chassis has been jacked up under the diff it can distorted making it hard to get the diff out, its no big deal to rem. & ins. the diff but some people seem to battle.
Brian
Opps, I forgot, hope you have relplaced doughnuts befor as that can be a pain (unless you have c.v.'s fitted)

[blueseamonkey]

The best hint I can offer is to get the car as high up as you safely can - it gives you a lot more room to manouevre the diff (you'll need it!) Also if you going to the bother of replacing the diff, if you can afford the cost you might want to replace the rotoflex driveshafts with the cv jointed or sliding splines types, it'll save dismantling the whole back end again later on, and the difference it makes is well worth it.

[Foxie]

Roy,

Timely you should ask, I have just this evening put a 3.55 diff in to replace original 3.9 in my Plus 2. Although I have had the diff out quite a few times for various reasons, here is what's fresh in my mind. Disconnect the drive shaft first. Cut a standard 1/2 spanner in half and use the short ends to get a good turn on the diff nuts once they are loose. Disconnect the inner do-nuts with the drive shafts LEVEL (a few concrete blocks in the boot) I have a Spyder IRS and can then swing the lh drive shaft out, if you have original rear susp, you will need to remove lh drive shaft completely. Use a heavy duty pipe clamp to compress the donuts and take the tension of the bolts. Jack up the car and take the load off the left hand spring. Remove the A-frame, disconnect lh h/brake rod, (don't stretch the brake line) Disconnect the stay rods and the mounting bolts on the diff. Slide it towards the left, it's a bit tight until the rh top lug clears the rh mounting and can lift and allow the lower rh lug to lift and clear the chassis, then it slides across nicely. I have a diff brace, it doesn't need to be removed, but it has been trimmed to match the top lugs. If the output shafts are tight, make up a slide hammer, a little heat in the ally casing also helps. Refill the diff with l1.2 litres of lube on the bench.

Don't forget a few cans of beer for reflection during those difficult moments !

Sean Murray

[Foxie]

Roy,

Cut a standard 1/2 spanner in half and use the short ends to get a good turn on the diff nuts once they are loose.
Sean Murray

My apologies, it's getting late. The above of course refers to the drive shaft to diff flange nuts.

SM

[alaric]

I had great difficulties getting the diff out. Removing the brace was ok but didn't give enough clearance. In the end I used a crowbar - gently of course. As already mentioned jacking under the diff can cause slight bowing of the chassis plate, which is enough to stop you being able to slide the diff out. So my advice is to bear that in mind and try not to get too worked up; if it's jammed, have a cup of tea, calm down, then carefully lever it out of the left hand side (UK passenger side).

Good luck.

Sean.

[Roy Gillett]

Thanks everyone. Fortunately I have already fitted Mick Miller shafts so I don't have to wressle with Rotoflexes. Clearly I shall see how much jacking has deformed my chassis by how tight it is.

Diff brace?? What and where is that? Mine is a '72 S130. Will that have one?

Building up my courage for an onslaught at the weekend.

Thanks again for the advice.


Roy

[alaric]

Roy,
I think yours will have a brace, as they were introduced on both the elan and +2; I forget exactly when. My car is an October '72 +2S130/5, and has a brace. It's nothing more than a flat bar located between the two top mounts on the diff, and is held in place by the uppermost housing bolt. It was fiddly to get at, but easy to remove.
Sean.