Service Procedures
Buyer's Guide

Changing the gear oil on a Ferrari 308, 328 or Mondial
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by Robert Garvin

My dream is to share what I have learned working on my 1975 308 GT4. I am working on a book "Ferrari Service for Dummies or What I Learned on the Internet" If you find any mistakes please let me know and I will revise it. As most of you may or may not know, I decided 11 years ago that I wanted to do my own work as I loved my car so much I couldn't trust anyone to touch my precious Ferrari. I started on the original Ferrarilist.com and met many members who guided me along the way, many are here now also. I also had help from several experienced Ferrari mechanics whose names will be withheld as not to embarrass them with my acquaintance! I am also on several other Ferrari lists, as I am a nut and have all this free time when I am not working 10 hours a day! :-) I hope you enjoy what I have written and I can help some other poor soul who was as lost as I was 12 years ago. Please give me feedback, as I am in the slow process of becoming an amateur Ferrari mechanic! Respectfully, Rob (Robertone) Garven (This article was originally published here on Ferrarichat.com)

Tools and or supplies needed:

1. (5) Quarts suitable oil (Swepco 201 80W-90, Agip Rotra LSX SAE 75W-90, Redline 75W-90) Oil needs to have a friction additive for the clutches in the differential! (Jonathan's note: Many people including me have had excellent results with Redline 75W-90 NS).
2. 10mm & 12mm allen hex wrench
3. 19mm & 22mm open end wrench
4. Suitable drain receptacle to catch and recycle oil
5. Rags or towels to wipe up spills etc.
6. Funnel and a piece of hose approximately 10 inches long.

Optional tools:

1. 1 creeper
2. 1 large piece of card board (To catch any oil that may splash.)
3. 1 box of latex gloves
4. 1 shop apron

Note: Never get under your car supported only by jacks. I have done this personally but I love my car more than myself. If you do this, make sure you have a good insurance policy. Your family will thank you, and at you memorial I will tell them I warned you in advance and try to buy parts off your car!

1. Make sure all work is done on a level and clean surface, you are sober and at least someone is around, (in shouting distance) in case you have an emergency. Get all the supplies you need ready at hand.

2. Raise car to a suitable height or use a lift, make sure the car is stable and even. If you use jack stands make sure that they are placed so that they will not get in the way of your drain receptacle and are more importantly placed on the main tube frame in the appropriate locations.

3. Remove the battery ground cable. I have a green spin off knob that disconnects the battery ground cable and is very handy, not only when working on the car but when leaving it for an extended period of time as not to drain your battery. Note: I have never had any battery drain even when the car has set for over a month, some models have more drain and even need a trickle charger to keep them charged for as little as two weeks! Jonathan's note: I never disconnect the battery to change the gear oil, but be careful not to short the starter motor to ground!

4. Loosen the 22mm transfer case fill plug first, because if you drain the transfer case and can't get the fill plug off, well you get the idea! (See below)


5. Place the receptacle under the transfer gear drain plug.

6. Loosen the transfer gear drain plug with a 19mm wrench.

7. Let the oil drain from the transfer case. There is not much oil in there but I place a receptacle and funnel under the hole to catch it all and leave it there for a while.

8. On the GT4 you must remove a rear aluminum heat shield cover that covers the gearbox overflow plug and hole.

9. Remove the gearbox oil filler / overflow plug with a 12mm allen socket, you will need an extension to reach it. It is on the rear of the gearbox near the left side of the differential.

10. Remove the gearbox drain plug with a 10mm allen socket wrench. This plug is located on the bottom of the car very near the engine oil plug. It is marked OLIO CAMBIO. I have heard several horror stories of someone draining the engine oil thinking it was the gearbox oil and well as stupid as it sounds, they were true stories with disastrous results.

11. Be advised there is allot of oil in there so after you loosen the plug, I hold it up to the threads after it is completely unthreaded and with one quick motion, move it away from the hole allowing the 6+ quarts of oil to drain into your suitable receptacle. If you are using one similar to mine that are available and given out by may local cities to help manage oil wastes do not forget to remove the cap, drain plug and pop the relief cap. I unwittingly forgot to remove the drain plug in the receptacle only to have the oil start to overflow and reach into the hot gearbox oil to remove it what a mess. Learn from my dumb experiences.

12. Let the oil drain for as long as you can. One hour is sufficient to drain almost all the oil.

13. I must mention here that I love the smell of gearbox oil. This has nothing to do with the procedure but what the hell I said it anyway!

14. Now your oil is probably all drained. I now clean the threads and magnets on the OLIO CAMBIO drain plug and replace it, along with the transfer case drain plug. It is recommended to use a new copper washer. I have heard aluminum is good also. I use a fiber one as it lets me tighten the plug with some fudge room. (See figure 14 & 15) With the metal washers any tighter than tight is stripped! I have also heard that if you anneal the old washer it works like a new washer. This entails holding it over the stove burner until it turns red hot then letting it air cool. I think this makes it softer, but remember I am not a scientist! If I were, I would be paying a real expert to do all this!!! Note: If you use the fiber washer I have had some that were slightly loose when I went to change to oil, so if you use one use it at your own risk. Ferrari recommends a NEW copper washer each time the plug is fitted! I am sticking to the fiber ones! Jonathan's note: new copper crush washers are available from all the usual Ferrari parts places for cheap money, like $.25 each, so just buy 10 of them the next time you order parts.

15. Now the fun part, adding the oil. I improvised an oblong funnel with a piece of hose attached to it to just fit into the transfer case fill hole and sit neatly above my ignition coils. I am sure there are a thousand ways to do this but after 10 different tries this is my suggestion as the most efficient way. You can of course fill the gearbox from the side filler hole, but that is very stupid, needs more tools and is totally unnecessary. The transfer case has a small hole that leads to the main gearbox so filling it from the transfer case hole has two main advantages. 1. It fills the transfer case without having to resort to some kind of measuring cup etc. and 2. It is much easier. Anyway, I have bought 5 gallon buckets of the Agip gearbox oil and had a swell time shaking them to get the limited slip additive to mix correctly, only to have to hold the heavy pail at an awkward angle for a long time to pour the oil in getting down off my step stool to check every once and a while that the gearbox is full and that oil is flowing from the rear side overflow hole. I have recently found that Agip sells the same oil in 1 liter containers making it much less exciting but also much less a pain in the ass. Several famous Ferrari Service technicians have recommended the Swepco 201 80W-90 gear lube. It is non-synthetic and has a limited slip additive in it also. I have heard so many good things about this gear oil that I drained out some fresh AGIP to fill the gearbox up with the Swepco. I will let you know how it works. One friend who uses it says he can shift into second when cold and that since it is a blue color it is easy to determine what fluid is leaking, if you have that problem! You know the old joke if your Ferrari doesn’t leak it is out of oil. Rolls Royce calls it “controlled seepage”!

You continue to fill the transfer case fill hole until oil starts to run out of the rear vertical gearbox filler hole. (This should take between 4 and 5 quarts). After cleaning the rear drain plug now is the time to replace it with your appropriate washer. Don’t get it to tight or you will strip the box (read here $$) or to loose and it will fall out. Go read Goldilocks and the Three Bears and you will find the right compromise. I always tighten it then give it one little extra umph. I use as short a ratchet, as I do not want to strip the threads.

16. It is now time to replace the transfer case filler plug. I always add an extra pint or so gearbox oil in before it is all closed up in case of leaks etc. I have also heard that 5th gear is the highest and sometimes get starved for oil and since I want a little extra insurance I add a few drops more.

17. That’s about it. I usually spend about 4 hours (or 4 days depending on my mood) wiping everything off and cleaning everything accessible as that is the type of guy I am! Now you can check your clutch alignment hole (in early 308’s), bleed your brakes or change your coolant, since you are already there!!


Legal disclaimer: I am not an expert just an experienced owner so the techniques and procedures I describe should be used with care and caution. Any damage incurred to vehicle, property or persons is the sole responsibility of the owner. Note: I have a sense of humor, you may not, please take this into account while reading this, as this is therapy for me!