Hello all, I have changed the engine oil and next on my list of setting baselines on my new to me car is changing the gear box oil. Per the instructions in the owner's manual, I should drain the oil from the bottom of the gear box differential as well as the clutch housing. I will drain it warm and probably let it drain overnight like I did the engine oil. The instructions then say to refill the gear box thru the fill hole on the lower edge of the gearbox until it is full to the lower edge of the hole - sounds simple. Then it states to add 3.8 fl. oz. of oil thru the fill plug on the top of the clutch housing. The question is how critical is the 3.8 fl. oz. - seems like a very specific quantity! In my research, I have found that the clutch housing and gear box pan are connected so I am confused on ths. One YouTube video showed filling the entire gear box (slowly!) from the top clutch housing fill hole until it overflowed the lower fill hole. Another thread on this forum noted draining 10 fl. oz. out of the clutch housing and therefore adding 10 fl. oz. back. So, what does the collective wisdom of the forum recommend? Thanks! Jon
Fill the transmission thru the top of the trasnfer gear 'hole' until it comes out the overflow. The correct amount will be left in the top and the trasnmission will be full. No neeed to measure.
This is a good tip since there doesn't seem to be a risk of air pockets in the transaxle case on these cars (on other cars there could be a risk when filling from a top hole, which is why some procedures call for bottom fill first). But I think this might benefit from some clarification -- fill through the top transfer case fill hole until it overflows out the rear transaxle fill hole. Would hate for someone to assume the wrong hole is the overflow. I hear so many stories about people overfilling gear cases. Also, the procedure in Carl's writeup linked above is a little out of whack -- he drains and refills the transmission before draining and filling the transfer case. They should both be drained at the same time before refilling (no matter how you proceed). Seemed like there was some confusion in the amount he added in his second step and that's probably why. Also it risks contaminating the new oil with some old oil.
The top transfer case plug is usually where the disimilar metal corrosion trouble is. Put antisieze compound on it when reinstalling. Also, go easy on the horizontal sump plug, it can strip fairly easily. The copper washers need to be snug to seal, but I use a dap of hylomar on the copper washer and avoid having to use too much torque on it to get a leak free seal.
The QV's, 328's and mondials have an internal oil pump and filter. Passenger side housing where the Speedo sensor is mounted. Every gearbox I've gone thru looks as though that filter has never been checked and cleaned. Requires removal of the housing.
Well, this is news to me!!! Any more information on this filter? Since I just finished changing my gearbox oil this morning it might be too late this time.....
You can see it on the parts diagrams -- I noticed it a while back when scanning over the parts manual for my 328 and thought that was a pretty tough way to access a filter screen. Image Unavailable, Please Login
I wouldn't lose any sleep over it. It's more of a "further disaster prevention screen" (to prevent any big chunks from a failure from entering the pump and causing even more problems) than a filter. It's very similar to the screen on the engine oil pick-up tube, item 25 here: Image Unavailable, Please Login and no one is cleaning that at every engine oil change . Sure, if you have gearbox bits blow-up inside, or if you're doing something big gearbox-wise anyway, or maybe after a lot of miles, it wouldn't hurt to add that to the list -- but it's not a typical service item.
Hmmm... Can't really argue one way or the other. Can only say what I've seen when pulling them apart. Built up sludge, diff clutch friction material. Those would be the best ones. Others? Well everything from bits and pieces and notably the most common... Silicone bits. The filter tube is actually quite fine in it's mesh and utilizes an o ring to insure no bypass.
Funny, post #8 was the first time I had ever heard of that filter! As the old saying goes, "...learn something new every day!" Re silicone bits - I'm a huge NON-fan of silicone sealant except when working on a bathtub or shower. Except in very rare instances, I don't use it for engine/transmission work.
Don't disagree that cleaning that screen, say, at something like every 30K miles, would be living a pure life worthy of Heaven, but would bet that the vast majority have never had it done. When I read your first post with "Every gearbox I've gone thru...", I thought to myself: "Well, if it needed 'going thru', that can't be good anyway" . Would argue that cleaning that screen at every gearbox oil change would be a bit of overkill, and there's not a lot of panic to change it on a well working car (i.e., just do it next time). Although do agree that catching excess Silicone blobs is probably it's best characteristic (so cleaning it at the gearbox oil change after a shift shaft seal replacement would make good sense and be justified), but still have a hard time calling it a "filter": Image Unavailable, Please Login
Don't forget to change the shift seals at some point if they haven't been changed prior. Engine oil can leak into the transmission and effect shifting. Or leak on the floor. Easy job when the engine is out. More cursing involved if engine is in the car.
Engine oil comes out black. Gear box oil look clean when drained. If the gear box oil is black the shift shaft seal is leaking. Otherwise it's fine. Also, if the gear box oil is clean the screen probably is too. Don't over thing this stuff.
How many transmissions do you see with a screen or filter? Very very few. Thats because very very few have oil pumps. The screen is to protect the oil pump. It protects the oil pump from being damaged by a large piece of debris like a small piece of broken tooth. Ferrari transaxles (not all) have had screens since the 275 transaxles and not until the 360 were they ever mentioned in the routine servicing schedules and for good reason. By the time the screen has enough debris to have an effect on flow the transmission will have an obvious problem and the debris in the screen will be a symptom, not a cause. It serves the same purpose as the screen on the oil pump pick up in the engine. Like John said, don't overthink it.
Another tip re changing the gear oil - the filler plug is often overtightened. If yours is, and you wind up sitting inside the trunk to exert sufficient leverage to crack the plug even w.a breaker bar like I did, you may unwittingly jostle one of the left-side wiring harnesses causing countless hours of trying to remedy non-functional speedo!
just drained my gear oil and re-filled with a pump, a shell pump I borrowed from a friend, we put the car on a lift, so much easier, I do this about every 3-4 years or with the major when I do cambelts, we did the gear lever seal on the previous service and it still seemed fine, I used a silicone seal instead, my gear oil looks really clean with every service, it's my third time changing gear oil in 10 and half years of ownership and about 12000 miles, the drainplug magnet shows a little metal debris each time I never had any sludge. I always had smooth gear shift and I can shift to 2nd within a few minutes on start-up. Around here Synteq or Motul 75w90 is quite popular among the guys and they are happy with that. cheers !! Johnny
Just a follow up. All went well with the gear oil change and the transmission shifts easier/smoother than before. So, happy with that. I used a handpump to fill - never again! Way too many pumps required. Will be purchasing a 12V drain/fill pump for future changes. The old oil was darker than the new oil. I might need to replace the gear lever seal as noted by other posters but that will wait until I change the motor oil next year. I will check the gear oil color then and decide if I need to change the seal then. Thanks again to all that helped! I did discover a leak at the passenger side drive shaft boot but I will start a new thread on that!
You don't really need any pumps at all. The drain (obviously) drains it all and you can attach a funnel to a piece of hose and, from the engine compartment, position the hose into the fill opening at the top of the transaxle and just pour the fluid into the funnel. You can measure the amount if you feel the need or just open the fill level plug and add fluid at the funnel until it just starts dribbling out of the level plug opening, wait until it quits dribbling from the opening then install the level plug and the filler plug.
