Creeper's Guide to Changing Your Diff Oil ---------------------------------------- Intro. -------- This is just a quick guide ive made up to help anyone out who wants to change the oil in their diff. It's by no means fully comprehensive and is based only my own experience from doing the job the first time. This is not the only way to perform the change but it suited me, having minimal equipment and only the usual level of backyard experience. Thanks. ------------ Before i start i wanna give credit where its due to both HSVSUX and ITSGMH, who both helped me out when I had stupid questions that needed answering. Thanks guys! oh and everyone else who replied to my many forum threads. Equipment/Tools/Materials ------------------------------------- I managed to do the job with only the below gear, but if you think something is better, obviously use that if its easier for you: 1x Socket Wrench 1x Extension Bar to fit socket wrench 1x reducer (not always necessary, depends on your socket set) 1x socket to fit diff bolts (sorry guys not sure of the exact size, but im sure you can work out which one fits...) 1x flathead screwdriver 1x small funnel 1x scraping 'tool' (i used an old paint scraper lying around, worked great. can also use a razor if need be) 1x bottle Kerosene/Turpentine Lots of gloves if u want to stay clean! Some rags. 2l ice cream container (or any other container if you dont eat ice cream for some strange reason) 2L Gear/Diff oil (my stock diff needs 1.7L when cold, but i could only get it in 1L bottles. The types that you can get are sae? 80w/90, 90, and LS/X90 (i think thats right, feel free to correct me) according to the valvoline book in the shop, my diff wanted LS90 so thats what i bought. Im pretty sure you can get away with using the cheaper stuff, but dont hold me to it.) 1x tube Red RTV silicone (this is what you actually use to create the seal between the housing and cover, make sure its high temp and high pressure. Now i know some of you will hang me for not using a gasket but having had trouble getting gaskets to seal properly before, i used RTV this time and it worked perfectly. So ha!) Disassembly ----------------- 1) with the handbrake on and car in park, jack the back up at either the left or right lift points. Support adequately 2) under the car, remove all diff bolts EXCEPT the top two. Loosen these about 3-4 full turns. (some need the extension bar, some dont) 3) position the container under the diff. This is where gloves are handy. you have been warned. 4) you might be able to separate the parts by hand, but i needed the flathead to lever the bottom open. Slowly but firmly crack the diff apart at the bottom, just enough to get the oil draining. 5) let all oil drain out 6) remove the last two bolts, and take the cover off completely Cleaning ------------- 1) to get rid of the gunk on the cover mating surface, lay it face down in some kero or terps and let it soak for maybe 10 minutes. 2) get your scraper and some elbow grease and get as much foreign matter off the mating face as you can. Remember, this is important as it can affect the quality of your final seal! 3) wipe down with kero or terps and set aside. 4) the above is the same for the diff housing surface, except obviously its quite hard to soak the surface. Just get a rag and soak it as best as you can. Your'e probably gonna just have to muscle it off though, so get to work. 5) take this opportuinty to clear the bolts and bolt holes of any rubbish, if only for cleanliness, but rather to ensure the bolts go in easily and hold strong. 6) flush the actual diff housing out with kero to get rid of the old oil, but make sure you wipe it out nice and dry after or the kero will thin your new oil. Reassembly ---------------- hopefully everthing has gone well, your parts are nice and clean and your ready to assemble. 1) get your RTV out, puncture the seal and cut the nozzle so the hole is about 5mm wide 2) on the DIFF COVER: run a nice ring around each bolt hole, check that there aren't any gaps. Important! Now 'connect' each ring with a nice thick bead , make sure there are no gaps again. You now have to let the silicone 'skin' - instructions suggest 10 mins, i found at this point the silicone was slightly tacky to touch but didnt string out when touched. 3) this is the part i found the trickiest, but only cos im impatient and easily frustrated. get under the car, and have the flathead and one bolt at hand. Position the cover over the housing but dont squash it on yet (dont worry if it touches lightly, no big deal) get the screwdriver and try and get it through one of the top holes and into the bolt hole in the housing, this may sound strange, but it acts as a guide. with the one bolt you have, screw that fingertight through the cover and into the housing, holding it in place. 4) by now the cover is probably sitting nicely in place, if not gently manouver it around until the holes line up. 5) now just screw the bolts in, but only until you can't do it anymore by hand. DONT FULLY TIGHTEN! this gives the silicone a chance to cure slightly away from its final position, hard to describe but it results in a better seal. 6) leave for at least 5 hours to cure, but longer is always better (cheers HSVSUX) 7) once the RTV has cured and is fully solid (but flexible) you can tighten the bolts up. this squishes the silicone inside, and because its cured, its kinda like a nice solid high pressure seal. No leaks hopefully! *nb you can trim off the excess rtv if you want, it looks better but i think its safer to just leave it alone rather than risk ripping a hole through your seal. Filling --------- 1) LOWER THE CAR! I negelcted this part first time round and overfilled by about 200ml. very messy! The space under the car gets tighter but its still enough to fill the diff. 2) wedge your funnel between the support bar running across the diff and the filler hole. it should hopefully reach the hole, if not just try different spots till it sits there by itself. 3) use whatever method you can to get the oil into the funnel! i used one of those little cups you use to fill the iron up, fitted into the minimal space fine. Keep going until the filler hole just overflows. dont get carried away and overfill, itll just waste anyway. 4) push the plug back into the filler hole, clean up and you should be done!!! Now im sure ive probably missed some things here, and like i said this isn't a definitive guide, but hopefully its helped someone out. I know i could've used it! Good luck guys, Creeper. Some original photos have not been recovered yet.

comprehensive, and well worded, I think you have done a bang up job, good on ya, cheerz morepsi

well done crepper, well written!!!!

Also what i have found is to hammer the diff cover flat where the bolts crush it out of shape with pressure, just tap the bolt hole back out flat, you will see what i mean when you look at it, this will give you a better seal, or as HSVSUX said use a diff cover off a ford, there alloy!

top work...

RTV all the way (if you use if correctly) gaskets suck! Well done.

Gasket AND RTV.......

Hey guys, thanks for all the positive feedback, i might have to write up another newbie guide soon Just to let yall know its 4 days on from changing my diff oil and there is not one leak from the RTV anywhere on the diff. Very impressed! cheers creeper Some original photos have not been recovered yet.

Quote: Originally Posted by CHAYSR Gasket AND RTV....... straight RTV is more reliable.

After i changed my diff over, now i have a leaking pinnion seal!

this will come in handy this weekend .... top stuff and thanks mate Some original photos have not been recovered yet.

verry well written,makes life easy for morons like me

well done creeper, keep up the good work

well done mate.

great article followed it step by step and got it done in no time, good work Crepper!

I will have to pass this on to a workmate, cheers!

Top article, just finished doing my car, though due to interruptions things had to be done differently. Saturday: One bolt was a little rounded on the head and I didn't have a hex style 13mm socket, only the type with all the notches around it, and it just slipped on the bolt. Off to Pep's for the right one, got the bolt out, drained the diff overnight, was too late to do anymore by then. Tip: Start the job early to give you time if things go bad, I started around 3.30pm, needed and got the socket at 4.45pm, just made it to Pep's. Sunday, clean old seal from housing and cover, not too hard. Make a seal on the cover, let it sit 20 mins, seems right to fit, but I made a mess trying to get it in (not much room with an adjustable panhard rod, being a bit thicker than standard, left hardly any room, next time I'll undo it at the diff and let it drop down, will give heaps of room), smeared RTV all over the place, had to clean up and redo the gasket. Then the MRS wanted to look at cars so I had to leave it, was about 2-3 hours before I got back to it, nice skin on it, still soft to touch so should be right. Unfortunately as I couldn't do it Saturday I ran out of time to let it set just out of place, had to fit it and do it up all at once, not much squeezed out and it looks like a good seal all round so should be right. Put in new oil, haven't driven car but no leaks yet. Fitted Penrite Limslip 90, was a clear blue liquid, old stuff was a grey/brown colour, and had some froth in it, not sure about that. All looks good inside the housing so I'll see how it goes over the next few days, hopefully I won't have to do it again.

mum is gonna be pissed when she finds out you used her iron filler

nice job m8. itl come in handy when i do mine

yeah good job nice article, will come in handy