I have a sierra diff with the 'push - in' type of driveshafts - the offside shaft slides into position perfectly however, the nearside shaft (which is the shorter one) goes in and the tips of the splines engage as the diff can be turned by hand, but then it 'clonks' and won't go in any further.

I have tried the offside driveshaft in the nearside socket - this sticks - 'clonks' - at the same point, but on jiggling it a little, it then goes in fully - a further 18mm.

Spent about two hours messing and jiggling with them up to now - run out of ideas....

I haven't filled the diff with oil yet, but it has got some in it as some dripped out when the car was on its side. - Maybe filling it will help?

There are pics of both the driveshafts and the diff in my photo archive.

I will be grateful for any advice or ideas / things to try.

[Edited on 13/7/09 by stevegough]

Make sure the circlip is not damaged or bent and is centralised in it's groove. A dab of grease can help hold in in place during fitting.

Thanks, Mike but these dont have a circlip or a groove for one. The shafts are bolted in place at the outboard end.

See enlarged photo - the grooves at the outer end of the splines can't be for a circlip as one wouldn't work at that point ?

[Edited on 10/7/09 by stevegough]
Rescued attachment driveshaft splines.jpg

I thought the Sierra diff had the circlips inside the diff rather than on the shaft, but might be wrong...

Having been up to my armpits in the flange and push in type diffs lately, maybe i can offer an insight here....

The push in types don't have retaining clips (the flanged Lobro ones have a copper faced circlip thrust washer that retains them.

Both pass through a guide and the splined portion of the shaft engages with the pinions (see diagram). Due to there being a lot of float (this is designed) in the pinions (thus the 'clonk' ), they can wander out of alignment with the end of the shaft.
Correcting this is easy with the diff casing open but trickier doing it blind.

Try turning the prop and repeat whilst hilding still the shaft that you can enter, causing the cage to rotate. Keep agitating while someone repeatedly offers the shaft into the splined socket. The hope is that gravity will pull the pinion into line as you rotate.



Differential

[Edited on 10/7/09 by Litemoth]

Litemoth, I think you have hit the nail on the head - you have put into words what I thought was the most likely answer. Unfortunately, I have actually been trying to do almost exactly what you have suggested for about 1/2 an hour - without sucess, but with not being quite sure what I was doing - there is, indeed some 'float' to the splined collars in the diff - the right one more than the left - the left one seems to stick almost as if it is dry - what do you think about me filling it with oil - might that help?

The only thing that makes me wonder is that the offside driveshaft will engage within a couple of seconds in the LHS - I have tried chamfering the tips of the splines slightly, but still no good.

Maybe I should take a leaf out of your book of black arts and take the backplate off?

The one driveshaft spline in your photo looks to have some surface rust on,give the spline a clean up may be binding going into the diff.

I had a feeling you were going to say that. How about some KY jelly?

Seriously though, you should be able to shine a torch down the hole and align the pinion by 'gluing' it with some grease and a wiggle with a screwdriver - at least enough to start the spline.


Is there any damage/foregn body in there? Was there a shaft in there before or did you buy it as is?

I'd say that a firm (but not hard) tap on the opposite end of the shaft (there are springs installed to thwart your efferts of course) should see that spine go in, if it does not then i think the back plate has to come off.

Filling with EP80/90 will be a waste at this stage but by all means lubricate/clean the splines and pinion up the shaft hole.

I doubt it's it but count and compare the splines on the two shaft ends......? I believe there are one or two variants with a spline extra. Try the other shaft in the hole?



[Edited on 10/7/09 by Litemoth]

[Edited on 10/7/09 by Litemoth]

If the one driveshaft fits both sides then i cant see it being the diff must be the shaft, damaged spline or surface rust

A couple of points-

1 - I have cleaned the splines and the shoulders up meticulously since the above photo was taken - they are now almost pristine! - mainly 'cos I thought the same as you Gary - the surface rust might be stopping it going in!

2 - I have counted the splines - both shafts have 23 and are, to the limit of my 50 - year old eyes identical.

I like the idea of sticky grease - especially if I use the right hand shaft to 'align' the grease - coated pinion first.

If I remove the backplate - what is likely to spring out or fall out etc? Are the gaskets readily available? (I have been able to remove the filler / level plug - another thread mentioned they are almost impossible to undo!).
What I am asking is how easy is it? - will it help? and is it easy enough to refit?

Regards, Steve.

Nothing will fall out except for oil. There's no gasket, so just clean up the surfaces and use some instant gasket on reassembly.

Personally, I'd try just a little more persuasion - of the block of wood and hammer kind. Stop being so gentle with it - it's a big hunk of metal

Liam

quote:

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Originally posted by Liam
Nothing will fall out except for oil. There's no gasket, so just clean up the surfaces and use some instant gasket on reassembly.

Personally, I'd try just a little more persuasion - of the block of wood and hammer kind. Stop being so gentle with it - it's a big hunk of metal

Liam

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It's worth popping the back cover off and having a look to see if there's any nasties going on.

Don't go down the route of mullering it with ever bigger hammers - it will lead to tears. Pragmatism is the key here methinks.

Ah yes, the cover bolts........

Thanks for all the advice and help, guys - now got it in - must have been the K-Y jelly!!

Seriously, used the gumming it up with grease, then a few taps on the rubber boot - covered edge of the joint with a mallet, and in it went!!

(Then I had to take it out again as I had forgotten the brake backplate !!)

Cheers, Steve.....now...on with the build!

OH !....... YES!........... YEs,......... Ahhhhh