Help needed with fluid leak on an R34 GT-R

[GSX-R35]

Hello everyone. I have an R34 GT-R Spec V here in the States - one of the few legally-imported Midnight Purple 2 ones - and recently noted it was leaking some fluid. I took it to a local mechanic and they said they could see what appeared to be leaks in two places - the transfer case and another further forward. Unfortunately here in the States it's very hard to find any shops or mechanics well-versed in Skylines but especially the R34 since only a handful have been imported legally so I was hoping I could get some help here to track down what could be causing the leaks and what fix is needed. I'd also appreciate any input on whether this is a sign of some major issue or not. The leaks aren't bad - it's mainly just a very slow drip - but of course I don't want to ignore a potential issue.

The car has about 140K of mileage on it. AFAIK the engine was rebuilt in Japan about 30K ago but other than a switch to an ATS twin plate clutch and routine maintenance the driveline hasn't been messed with. The car's been running well and I haven't noticed any changes in driving behavior before or after discovering the leak.

Here are photos the mechanic took of the leaks. I'd like to mention that I myself have just fairly basic mechanical knowledge (I can do basic maintenance and have done simple mechanical work like installing bolt-on parts like exhausts and such but I leave major stuff to experts) so please forgive me if I seem clueless on certain things. Thanks in advance for any help.

[Duncan]

OK, you are right, your mechanic doesn't know what they are looking at.

The best way to investigate an oil leak is to thoroughly degrease any apparent leak, drive for a day or 3, then put back up on the hoist and check again.

The first oil is almost certainly from when the oil filter was changed (unless the filter is relocated, you can check by looking under the front 1/3 of the plenum for the oil filter. From there you can see that whenever you change the filter, you will drop 300ml of oil on top of the front diff, which then runs down the front of the front diff (pic 1, 2, 7) and steering rack (6)

The other point that appears to be leaking is the ATTESSA/4wd actuator at the rear of the transfer case, the leak might be either the line that goes into the actuator or the flange where the actuator bolts to the transfer case. It is hard to tell because there is a bit of oil there. Step 1 I would back off the nut on the hose that goes into the actuator about 12 turn, then tighten it up again, this is a common leakage point over time.

[GTSBoy]

Duncan beat me to it. What he said ^^.  But making sure to interpret 12 turn as 1/2 turn.

[Duncan]

lol yes, / makes a big difference

[joshuaho96]

1 hour ago, GSX-R35 said:

Hello everyone. I have an R34 GT-R Spec V here in the States - one of the few legally-imported Midnight Purple 2 ones - and recently noted it was leaking some fluid. I took it to a local mechanic and they said they could see what appeared to be leaks in two places - the transfer case and another further forward. Unfortunately here in the States it's very hard to find any shops or mechanics well-versed in Skylines but especially the R34 since only a handful have been imported legally so I was hoping I could get some help here to track down what could be causing the leaks and what fix is needed. I'd also appreciate any input on whether this is a sign of some major issue or not. The leaks aren't bad - it's mainly just a very slow drip - but of course I don't want to ignore a potential issue.

The car has about 140K of mileage on it. AFAIK the engine was rebuilt in Japan about 30K ago but other than a switch to an ATS twin plate clutch and routine maintenance the driveline hasn't been messed with. The car's been running well and I haven't noticed any changes in driving behavior before or after discovering the leak.

Here are photos the mechanic took of the leaks. I'd like to mention that I myself have just fairly basic mechanical knowledge (I can do basic maintenance and have done simple mechanical work like installing bolt-on parts like exhausts and such but I leave major stuff to experts) so please forgive me if I seem clueless on certain things. Thanks in advance for any help.

The front diff/steering rack leak area could be a lot of things. Could be someone spilled the contents of the oil filter all over the front diff as others have said. The other possibility is the o-rings on the oil cooler are leaking. There's two o-rings, one on the oil cooler itself to the oil filter housing, another in the eye bolt that bolts the cooler to the oil filter housing. If you don't want a huge project disassembling the whole intake side of the engine you can reach from below behind the front diff using extensions and wobble joints to get the socket in the right place to undo it. Then you get to fight the hose clamps that feed coolant into that heat exchanger. Another possibility is a valve cover leak but that should be obvious from the top of the engine if you look carefully. Another possibility is that the front diff itself is leaking oil from somewhere like the front cover or axle seal. In my case it was all three and I didn't know until I fixed one problem only to discover despite cleaning off the front diff and everything else I was still getting oil at the bottom of my front diff.

I have started doing all my own work for these cars because I've realized that they aren't that complicated by modern standards (see: BMW N63, VR30DDTT, etc) and at the end of the day nobody is going to be as invested as you are in making sure the job is done correctly. Basically every time I have given the keys to a mechanic to let them do anything they have damaged something, usually discontinued and a huge pain to fix. Mechanics in my area are often used to being able to say that it could've been any previous mechanic that caused a problem but I am doing all my own work so often that I can pin down exactly who did something and it has turned into a huge fight every time I confront one about something I'm almost certain they did.

[GSX-R35]

Thanks for the helpful replies guys! I'll get back with the shop and see how it plays out. It would make sense that the oil at the front is from spilled oil - the car did have an oil change fairly recently and the filter is in the stock location. I'll bring up the suggestion on the hose for the transfer case and see how that works as well. Really appreciate the help and quick responses.