HOW TO: Differential, Manual Transmission & Engine Oil changes...

Well, yesterday I decided to change out all the fluids underneath the car. I changed out the fluids in my diff, transmission and the engine oil. I had my camera with me, so I decided to take a few pics and share them. This is probably one of many how-to guides on changing fluids... but this is my version, and I figure the more tech info to share... the better.

Keep in mind this is the first time I ever changed the differential and manual transmission fluid on the GTO. It's so easy, a caveman can do it.


First off... here are the fluids that I used:



Castrol Syntec 0w-30 motor oil (aka German Castrol or GC)
K&N Oil Filter, HP-1007

Torco RGO gear oil, 85w140
Torco Type F Limited Slip additive

Royal Purple Synchromax transmission fluid

I also had a hand pump that I bought at Advance Auto Parts. All it is, is a long tube that fixes to the end of the bottle. You squeeze the bottle and the stuff goes in.

Here is the hand pump. I purchased it from Advance Auto Parts for a couple bucks. The tube for it was actually longer, but I cut it in half so I can get to the hard to reach places easier, and it's also easier to pump when you have half the hose.





REAR DIFFERENTIAL:

Last year I suffered from the dreaded "whine" some of our diffs can make. So the dealer replaced the entire rear end, which you can read about here. Some people say you should do a 500 mile break in with the new diff, some don't. I decided to play it safe and break it in. After the 500 miles was up I wanted to swap out the stock fluid for something a little tougher.

Here is a pic of the drain and fill holes:



It takes a 30mm wrench to get the fill plug off, and a 15mm to get the drain plug off.

I drained the stock gear oil. It was a thick, gray-ish color. I could also see some metal flakes mixed in with the fluid. It wasn't alot, but enough that you could see it pass by. Oh, and like alot of people have said on here... this fluid STINKS! Once the fluid was drained, put the drain plug back in (duh).

Next, I used the hand pump and squeezed about half a bottle of gear oil in. After that, I measured 2oz of friction modifier and poured it into the half full Torco bottle. I did this so it would be easier to get the fricion modifier mixed in with the gear oil.

After adding the friction modifier, I opened up the other bottle of gear oil and added it to the half full bottle w/ the friction modifier. I did this because with a hand pump, it was a MAJOR pain in the ass to try and squeeze out the last half of a bottle. Either that or it was just me.

You can tell when you have enough fluid in the diff because the oil will start to come out of the fill hole. Once that happens, just put the fill plug back in, and you're done with the rear differential.




MANUAL TRANSMISSION:

Next I decided to up my tranny fluid from stock to Royal Purple. After reading alot on here, it seems the RP Synchromax was the way to go. So I figured since I was changing out the gear oil and the engine oil, why not change the tranny oil while I was at it?

Here is a pic of the drain plug. It's located on the rear passenger side of the transmission. I used a small rachet (with no socket) for this. Be careful, this fluid like to spew out... so just be prepared.



Once all the fluid is drained and you replace the drain plug, you have a few choices on where you want to fill from. You can remove the back-up light switch on the passenger side of the transmission, you can remove your shifter (from inside you car), or you can use the fill plug, which is located on the drivers side of the transmission. I decided to use this fill plug, which is pictured here:



Filling the transmission was alot like filling the diff. I used the hand pump, and squeezed in the tranny fluid, half a bottle at a time, until tranny fluid started coming out of the fill hole. Once this happens, just put the fill plug back in. Keep in mind if you use this fill hole like I did, you'll only get approx. 3.8 quarts of tranny fluid into the transmission. The owner's manual calls for 4.6 quarts. So how do you get the remaining 0.8 quarts into the transmission then?

Right here...



On the upper front passenger side of the transmission you'll see this. It is the reverse sensor switch. This is what tells your reverse lights to come on when you shift your GTO into reverse.

Disconnect the wiring harness from the sensor, then get a 7/8" wrench. I tried using a socket, but the deepwell socket was too tall, and a regular size socket is too small. Using the wrench, take the sensor out of the transmission. This may take several minutes if you're using the wrench, so be prepared for alot of 1/4 turns until it comes out.

Once you have the reverse sensor switch out, start to fill your transmission until the fluid starts to come out of the reverse sensor hole. put the reverse sensor switch back in, reconnect your wiring harness and you're done!

NOTE: You can start to fill your transmission straight from the reverse sensor hole and completly avoid using the Fill Hole on the driver's side. I only did the Fill Hole on the driver's side because I found out about using the reverse sensor hole after the fact (ALWAYS refer to your owner's manual before changing fluids and you can avoid this). (Thanks Fox Mulder, why2kmax and Cyclone Chris)

ENGINE OIL:

Everybody should know how to do this. I don't have many pics of this because the battery on my camera was dying, so use your imagination.

Just remove the four bolts holding the skid plate (13mm). Once removed, you'll see your oil pan and oil filter. On the passenger side of the oil pain is your drain plug. Use a 13mm wrench (thanks Kanding) to get it off. Once the oil is drained, replace the drain plug. Next, remove your oil filter. I use K&N oil filters, so I can use a 1" wrench to get the filter off.

Next, get your new oil filter ready. I like to fill my oil filter up with oil before putting it back on. It's a little easier on the car during that first start up. I also take a little bit of oil on my index finger, and lubricate the seal on the oil filter before screwing it back on.

Once you have the oil filter on, go ahead and put your skid plate back on. I took this opportunity to replace my stock skid plate with a fancy new one that I fabbed out of a spare stocker I bought in the For Sale section. The thread about my fancy new skid plate is found here.

Here is a pic of my new skid plate on the car. Sorry it's so dark...



With everything under the car in order, go ahead and pop your hood and fill your car up with your oil of choice.




HELPFUL HINTS:

- Buy extra fluids. If you're using a hand pump like I did, having an extra bottle of tranny/gear oil makes things a little easier. With the hand pump, I could only get about half a bottle into the car before I couldn't squeeze any more out. I would then open up another bottle and squeeze about half of it out until I couldn't squeeze any more. Then I would pour one half full bottle into the other half full bottle and repeat the process until my fluids were topped off. It was a long process because I didn't have gravity working with me (couldn't get the bottle in a good position for that). Hard to do? No. Just took a while.

- Bring something good to measure your friction modifier. I had to eyeball about 2oz of friction modifier. It would be nice if you could measure right out of the bottle, but you can't. Next time I have to change out the diff fluid, I'm going to buy one of those plastic syringes (the kind that you would use for children's medicine).

- Invest in magnetic drain plugs. I forgot to do this, but next time I change out the engine oil, I'm going to replace my drain plug with a magnetic one. This is purely optional, but you'd be surpised what that little magnet at the end of the drain plug can pick up. I suppose you could also do the same thing with the differential's drain plug. Having a magnet in there could catch any metal shavings before they get grinded between gears.

- Always remove the fill plugs before you remove the drain plugs! Not because you have to, but it's alot better remove the fill plugs first, just incase you find out you don't have the right tools, or can't remove the drain plugs. Nothing is worse than draining your fluids in your diff or tranny and finding out you can't get the fill plug off! (thanks 2k6 GTO)

- Check you tires for strut rub.Whether you're on jacks or on a lift, while you're under the car you might as well check your front tires for strut rub. What is strut rub? This topic has been extensively covered on this forum, so a quick search for "Strut Rub" will bring up plenty of helpful info.



Anyway, I hope this tutorial will be helpful to some of the newbies out there who want to do their own maintenance on their vehicles. I'm no pro by any stretch of the imagination, so if there are better methods out there, please feel free to post them up here.


Grave

This is a great post!!!! Thanks for including the pictures and text. Once it warms up a little and I bring the goat out of hibernation I am planning on doing both these lube swaps. I will only do this outside as Rear end lube / outboard lower unit lube stinks pretty bad and I dont want that rancid smell in the garage.

THank you so much for the details about the rear end. You said "put the drain plug back in duh". Well on an outboard you actually leave the drain plug out and fill through the drain plug until fluid emerges out the top hole. So your comment was actually very helpful. And no its not just you - pushing a viscous lube through a handpump can be a pain in the arse. I too do the fill the half bottle trick rather than pump out the last little bit.

I just have a couple questions:
1) would you mind posting the part numbers and a recommended vendor name for the RP and the Torco gear lube and additive?
2) where did you get the skid plate? Very cool!
3) Do any of the board sponsors sell the magnetic drain plugs (good idea)?

Thanks again for the information. C'mon spring!

In the M6 trans, if your car is level or even on ramps (front), you will only get 3.7 qts +/- .2 qts in before it runs out. The reccomended amt is 4.6 qts. you either need to fill from the reverse switch ( remove on pass side) OR jack up the drivers side about 19-21 inches (support it well) and then pour in the other half qt. through the fill hole It DOES make a difference in feel.

Quote: Originally Posted by borntosnag... I just have a couple questions: 1) would you mind posting the part numbers and a recommended vendor name for the RP and the Torco gear lube and additive? 2) where did you get the skid plate? Very cool! 3) Do any of the board sponsors sell the magnetic drain plugs (good idea)? Thanks again for the information. C'mon spring!

For the RP, I bought it on the Air Force base I'm stationed at. If it's not available in your area, and you're looking for a sponsor who sells it, I know Speed Inc sells Synchromax. There are probably others, but they're the only one that I can think of off the top of my head.

For the Torco, I went straight to their website: http://www.torcoracingoils.com/. Click here for the RGO gear oil, and here for the Type F friction modifier.

The skid plate I made myself. I bought an extra one in the For Sale section, then had the holes cut into it, then primed and painted it.

I'm not sure if any of the sponsors sell any magnetic drain plugs. Probably some of the Dealership sponsors do. I think you could just go to a GM dealership and get one, or I believe some auto parts stores carry them as well.

Quote: Originally Posted by why2kmax... In the M6 trans, if your car is level or even on ramps (front), you will only get 3.7 qts +/- .2 qts in before it runs out. The reccomended amt is 4.6 qts. you either need to fill from the reverse switch ( remove on pass side) OR jack up the drivers side about 19-21 inches (support it well) and then pour in the other half qt. through the fill hole It DOES make a difference in feel.

Cool... thanks for this bit of info. It makes sense too, because the reverse switch is a little higher on the tranny than the fill hole on the drivers side. I was wondering why I had some left over tranny fluid.

Luckily, my GTO isn't a DD. Probably later on this week I'll take it back to the auto hobby shop, get it on the lift, and fill the remaining fluid through the reverse switch. I could probably do the same through the top of the transmission via the shifter, correct?

On a side note... yes, I noticed a difference from switching from stock ATF to the Synchromax. The shifts are smoother, and it seems to shift just a little bit easier. I'm definately glad I decided to swap this fluid out.

Once I get to adding the remaining tranny fluid, I'll edit the original post, and add that bit in, complete with pictures. Should be later this week.

Great post, very informative, we really appreciate the time you took to detail the instructions and include pictures. Thank you very much !!!

This is a great post, it should be in the Knowledge Base.

Question - Dont most fill the tranny through the back up light switch?

Quote: Originally Posted by LS2 Pontiac GTO... Question - Dont most fill the tranny through the back up light switch?

I'm not sure, really. I just chose the plug labled "Fill", it seemed most appropriate. But, like why2kmax mentioned, even if you use the fill hole that I used, you may still need to use the backup light switch. I believe it's because it's a little higher up on the tranny than the fill hole, so if you fill it from there you should be able to get more fluid in there. I'm gonna check this out later on this week, and I'll change the original post as needed.

The manual specifies 4.6 quarts and says to use the reverse light switch as the fill, and that's what most people do. However there has been some debate over why that is and whether the fill plug should be used instead with a 3.8 quart fill amount.
There have been a few people who spoke directly to Tremec and were told that 3.8 is the correct capacity for the T56 even with the slight angle as mounted in the GTO.
Personally I went with the fill plug/3.8 quart amount when I changed my trans to Redline D4 ATF. That was a year and over 12K miles ago, and I've had zero trans issues. I have also never had any problems getting into reverse, this has also been reported by others using the lower fill amount.
You can go back and read through the discussion threads and decide for yourself how to proceed. If you do use the reverse switch hole, be sure to keep track of how much fluid is going in because a lot more than 4.6 quarts will go in there before it starts to run out.

http://www.ttcautomotive.com/English...ice_Manual.pdf



On page 1-1 (page 3 on the PDF) this manual recommends filling via the fill hole. Although it also throws in there to also check your owner's manual for specific lubricant amounts. If anything, I'll go by what the vehicle manual dictates.

My dealer used the fill hole and put in 3.8 qts. I ran it like that for 20,000 miles and just changed it last saturday. This Time I did it using the fill hole and jacking it up 19" on the drivers side to get the extra in. As good as the shifting felt with 3.8, it feels even better with 4.6. Read these threads for additional help and why the fill hole doesnt quite work for us.

http://www.ls1gto.com/forums/showthr...eferrerid=1591

and

http://www.ls1gto.com/forums/showthread.php?t=27870

The last post in the 2nd one is how I ended up doing it. Lots of good tips and links to other posts that help.

sticky material...i was just wondering about all of these

Good post, but check the oil drain plug size. I'm pretty sure its 13mm rather than 15mm. I think its the same for the skid plate bolts.

Maybe I'm sloppy, but when I change the GTO, oil always seems to seep from the fill tube onto the engine and passenger side header. The first time this happened I didn't notice it until I started the engine. In a few minutes when it got warm again, the oil began to burn off any wispy white smoke came from the engine bay--scared the **** out of me--I thought the oil somehow leaked out somewhere and my engine was burning up. And I really love the smell of burned oil in my car.

I have 2 questions

1. How did you get your stock rim so clean lol
2. The fill holes on both the tranny and differential seem to be on the side as oppossed to the top....how do you fill something up completely if you are filling it from the side and not the top.

p.s. If question # 2 is dumb just let me know I am a dumb college student that is trying to learn about cars.

Quote: Originally Posted by Kanding... Good post, but check the oil drain plug size. I'm pretty sure its 13mm rather than 15mm. I think its the same for the skid plate bolts.

DOH! You're right. 13mm for the skid plate/oil pan drain plug. God, by the sound of it, you'd think I never changed my oil either (unlike the tranny and diff, I've done engine oil plenty of times). Honestly, I have no idea how I made that typo. The diff is 15mm, though. I'll edit the original post. Thanks for catching that. I gotta lay off the crack.

Quote: Originally Posted by pallidamors... I have 2 questions 1. How did you get your stock rim so clean lol 2. The fill holes on both the tranny and differential seem to be on the side as oppossed to the top....how do you fill something up completely if you are filling it from the side and not the top. p.s. If question # 2 is dumb just let me know I am a dumb college student that is trying to learn about cars.

1. Well, my car isn't a daily driver, drive it on the weekends, but only if the weather is nice. So keeping the car clean is easy. But those wheels are a PITA to clean. Which is why I can't wait to buy my new Michelin Pilot Sport PS2's for the VZ Monaro wheels I have sitting in my garage.

2. You don't have to fill either the diff or tranny to the brim. Same with the engine, you don't fill that until oil comes out of the cylinder head! For the diff the only place to really fill it is on the fill hole, so once the oil starts to trickle out of that hole, you're good. For the tranny I used the "Fill" hole that's stamped on the transmission itself. But after why2kmax pointed out those two threads (see above) I did some more searching on here and there seems to be debate whether you put 3.8 or 4.6 of tranny oil into the transmission. If you put the oil into the Fill hole, you'll get 3.8L. If you go through the back-up light switch, you'll fill to the owner's manual specification of 4.6L. I'm gonna follow the books recommendation and fill to the 4.6L sometime later this week and update the HOW TO accordingly.



And I appreciate all the help/pointers some of the more experienced forum members gave to this thread. I suppose this HOW TO is going to be a Work in Progress, as I want it to be as detailed and accurate as possible... so I'm going to continually have to improve on it in order to make it useful to the average not-so-technical car guy (like me).

Thanks this was extremely helpful

Good post...I was thinking about going with Royal Purple in the diff, at least thats what everyone is recommending.

Quote: Originally Posted by Grave... DOH! You're right. 13mm for the skid plate/oil pan drain plug.

The only reason that I remembered that was I used a 1/4" socket the first time I changed the GTO oil and broke it, then ran around to three stores looking for a 1/2" 13mm because the first two that I went two were sold out of that size. A 30 min job instantly turned into a 2 hour job.

Has anyone had leakage from using Royal purple products? I will never use that crap again! Not only was my diff erratic from using it in the rear w/o a bottle of slip(it says on the bottle none requires) it caused a pinion leak, I didnt even overfill it. Same with my trans, word of advice use a bent WD-40 spray tip and fill the trans up thru the backup lamp switch about 1/2 below the threads, I found out that filling it up all the way causes some frothing and leaks

Thats a great tutorial. And with your lightweight skid plate I can see why you say to take it off but with my 12-15 lb. beast I just remove 3 bolts and pivot the plate. Whats up with the Dexron III label saying do not remove the fill plug and I can't make out the last word. Educate me about why we cant fill the tranny through the fill tube. Thanx.

When I changed my tranny fluid, I used some 3/8" clear plastic tubing I found lying around the house that I routed up through the engine compartment. I stuck one end in the backup light switch hole and filled the transmission from the other end of the tubing. I cut the lids of the RP bottles so they fit inside the plastic tube and then poked a small hole in the bottom of the bottles. Gravity did most of the work. I had my 9 year old son stationed under the car to watch until the tranny was full.

Very helpful.

Do you have a picture or link to the pump you used?

yea, the tranny gets filled from the Backup lamp switch hole. I looked at the GM Service Manual and it tells you to use the Backup switch also. I was never able to get the full 4.6 quarts, until I used that hole.

Once this article is updated I'll go ahead and put it in the knowledge base section.

Quote: Originally Posted by gtochris... Very helpful. Do you have a picture or link to the pump you used?

Here is an item very similiar to the one I used, click here. Once I fill the correct amount of oil into the tranny, I'll take a quick pic of the one I used.

Quote: Originally Posted by Cyclone Chris... Once this article is updated I'll go ahead and put it in the knowledge base section.

Thanks! It'll take no time to pump a quart of tranny oil, so I'll see if I can get some lift time after work today and git er' done.

Don't forget to use that white high temperature Teflon paste (Permatex) on the threads to help keep it from leaking...
Also, always remove the fill hole plug first, in case you can't!

Ok, tutorial updated with the reverse sensor hole method for filling up the transmission.

I copied over this article into the knowledge base.

http://kb.ls1gto.com/KB/article.aspx?id=10377

Thanks again Grave

Quote: Originally Posted by Cyclone Chris... I copied over this article into the knowledge base. http://kb.ls1gto.com/KB/article.aspx?id=10377 Thanks again Grave

No problem, just wanted to do my part for the community.

good post, looks pretty easy going on the diff and tranny fluid, I will have to give it a shot

Just wanted to point out the diff should be filled up on a LEVEL surface. If you jack up the rear, you'd put too much. I was able to change both diff and engine oil without lifting the car at all, but I know not all of you are 155 lbs.

One trick many use is to find an inclined driveway (many have one in their houses -not me) and have the rear tires at the edge, which will give you the level attitude needed, plus you can get underneath a lot easier. Later.
JC