Thread: TeamFA's Gearbox Repair '02 Defender R380

I'm curious about the sealant question as well. I had planned on using Permatex Ultra Blue, as I've been using it on pretty much everything automotive (except where near fuel injection sensors) for years, and never had a leak...

No idea on the technicalities.

Just the first time I did it, using 518, it leaked between the main and extension housings.

Second time using the LR RTV silicone it didn't.

That LR one is intended for gearbox casings / timing covers etc and seems pretty good.

I also used in on my Transfer case and it is all totally dry still.

Any decent sealant would probably be fine, but i didn't have a lot of luck in this instance with 518. (I have used it succesfully when asembling td5 heads though.)

The other advantage of the stc50550 is that it is black.

come on Pete, your the engineer ...My guess is where there is a gasket between to surfaces that will see alot of load, say like the swivel ball to axle flange, it is best practice to use the thinest gasket possible, ideally no gasket at all. For other places non structural, say like the cover of the transfer case, it doesnt really matter.

The problem is in reality is the quality of materials use and the standard of machining.....

I had no idea what the LR sealant was, but now that I see it is an RTV, Im guessing that wont be a problem. I have had good results with Permatex Ultra black on drive flanges and transfer case sump cover. This is Permatexs premium RTV sealant....it is also black.

Now in good practice I probably should not have used it at the drive flange. Im guessing from an engineering view point the flange to hub wants to be friction fit like the axle housing flange is with spindle and swivel ball....

I could be wrong though

Do a Google image search for that part number and it comes up with Loctite 598, 5910, and 5900. I've got no idea what the difference is, but it all seems to be a black RTV.

I wouldn't worry too much about where you use it, subject to the usual cautions, etc., etc. Just don't use enough to seal a bathtub.

In relation to sealing the gearbox together - it's not exactly which RTV you use, but how it's applied. In short, make the mating surfaces surgically clean, apply a continuous bead and then have a cup of tea. Yep, wait 10-15 min, and then assemble. So far I've assembled a couple of R380's and no leaks. My fav RTV is Silastic 732 in black. Just a note - if you remove gaskets and go with RTV, you have to re-do the preload/shim.

Originally Posted by langy

In relation to sealing the gearbox together - it's not exactly which RTV you use, but how it's applied. In short, make the mating surfaces surgically clean, apply a continuous bead and then have a cup of tea. Yep, wait 10-15 min, and then assemble. So far I've assembled a couple of R380's and no leaks. My fav RTV is Silastic 732 in black. Just a note - if you remove gaskets and go with RTV, you have to re-do the preload/shim.

Suffix L boxes are only sealed with sealant. No paper gaskets at all so that shouldn't be an issue in this case.

Originally Posted by Psimpson7

Suffix L boxes are only sealed with sealant. No paper gaskets at all so that shouldn't be an issue in this case.

That's what I was thinking... cool...

Okay, now that we have surmounted a seperate obstacle (getting loan approval from the bank to buy our 100 acres at Inverell), we're just about ready to order our parts.

I've looked at the kit required to do the end float measurement, and figure I can purchase for about $100 - the dial indicator and the clamp.

I figure this is a pretty rarely-used item, so I'm a bit disinclined to buy the kit. Normally I don't shy away from buying new tools, though...

Does anybody know if these things can be hired from somewhere?

Alternatively, does anybody have this kit that they could loan me in a week or two? I can happily collect from the Brisbane/Sunshine Coast extended areas...

Cheers!
Michael