27 replies to this topic

[Neil7744]

Hi,

Im currently overhauling my engine which ive removed from my mini.

I need to replace the gasket that fits between the gearbox differential housing and gearbox sump. I spoke to a friend who told me this is pretty simple, bend back the metal clips locking the bolts in place and simply take it off. He told me there was a spring and ball bearing that may pop out, and this is to do with oil pressure relief or something????

Anyway...can anyone give me any pointers. Currently my engine and block are out of my mini and the block is bolted to the gearbox. I dont plan to speerate the two.

thanks

[Pauly]

Ball and spring will pop out when you take the output side covers off, this is the detent spring for the selector. When putting it back together check your pre-load on the diff bearings, im sure guess works will be along to give you the details on this, I forget no sooner I have done it .

[Neil7744]

ahhh yeah, i read baout that in Haynes manual.

problem is the haynes manual (in my opinion) is rather poor when it comes to gearbox information.

so it should come off in one piece then?

Should i remove the differential unit first then split both output side covers, or do it the opposite way round?

[Kerrin]

1. Drain oil.
2. Revove driveshaft inner CVs from both sides of housing.
3. Remove the output shaft covers from each side 1/2" or 7/16 socket, the right hand cover holds in the gear detent spring.
4. Knock back any lock tabs and remove nuts/bolts to remove diff housing.
5. Leave diff and any shims on the bearings, clean off all gaskets, and remove oil seal o ring from round detent spring.
6. Put new o ring back and replace gaskets.
7. put it all back together with the correct torque settings, and use new lock tabs which should be knocked over once torqued up.

Are you sure it is the gaskets, as most of the leaks are caused by the rod change seal on the gear selector which is a simpler job. it is probably best to do ths seal as well while you have it apart.

Edited by Kerrin, 15 March 2010 - 09:39 PM.

[Neil7744]

first of all...kerrin you legend

this is exactly what i wanted. Yeah im pretty sure the leak is coming from there, however have gone into this 'engine overhaul' thing to start with just the intention of painting it up and changing ancillaries. After thought though, im trying to get round as many gaskets changes as possible, but this one is the issue im most concerned with.

I also need to check the selector rod for 'play' according to the workshop manual and haynes. This is something else i need to look into aswell.

thanks

[Kerrin]

There is a repair kit from mini spares which includes a new oil seal and also a little alloy spacer that will hold the rod in a better position and stop the seal wearing again.

[Neil7744]

can u link it for me?

[MRA]

Personally I never use locktabs...... they are so 50's ................. they are more likely to "give" and release the preload torque on the bolts or studs used to hold the diff in position

Also check the inner CV pot joint in the side cover as these wear and allow oil to leak past them

[Neil7744]

ok...thankyou very much for your help.

[david036]

from my understanding off diffs etc, when you refit the diff to the gearbox on earlier engines you don't use gaskets. Just sealant.
They cause more issues than they solve. Always thought this was strange my self, but after changing a few lately this is right as all the ones i've removed didn't have gaskets on.

[Neil7744]

hmm...interesting.

[Sprocket]

from my understanding off diffs etc, when you refit the diff to the gearbox on earlier engines you don't use gaskets. Just sealant.
They cause more issues than they solve. Always thought this was strange my self, but after changing a few lately this is right as all the ones i've removed didn't have gaskets on.

Late gearboxes do not have gaskets. you can use the rule of thumb, that if the diff housing is retained with bolts, there is no gaskets between the main gear case and diff housing, and that if the diff housing is retained with studs, gaskets should be fitted. I have rebuilt a few gearboxes where gaskets were fitted where they should not be! and this was double checked by measuring the roundness of the bearing housings If you have a gear case that uses no gaskets between the diff housing, make extra sure that there are no dings and knocks on any of the mating surfaces.

Also, I don't see the locktabs giving under torque or load, considering that the material they are made from is harder than the gear casings and the bolt torque value is not exactly huge. Remove the lock tabs by all means, but make sure you use some sort of thread locking compound. Personaly, I use the locktabs on the diff, as that was the only place the factory used them on bolts on late A+ engines, right up untill end of production. There must have been a valid reason

[Dan]

As Sprocket suggests, you can't just decide not to fit gaskets to your gearcase any more if it was made to use gaskets. The cases are machined to either use gaskets or not. The diff housing forms bearing shells for the two diff bearings and as such they are line machined either with or without a tollerance for gaskets taken into account. This is why diff housings and gear casings are matched pairs and not fitting a gasket that is meant to be present is as bad as fitting the wrong main bearing shells to an engine.

[Kerrin]

Gear oil seal..

Linky for you

Interesting about the lack of gaskets on the later gearboxes. All of mine have evidence of previous strip downs so I dont think I have an unmolested one.

Edit

What is the correct sealant to use?

Edited by Kerrin, 15 March 2010 - 10:56 PM.

[Guess-Works.com]

From the above script it's suggested that you're going to attempt this with the engine in situe. Good luck.