datis250

Hello everyone,

i Am making this post as it seems quite rare to happen on our cars. I took my car in for its oil change, and my friend noticed I had a front diff leak. I had no discernible spots on my driveway/garage, so it was quite slow.

symptoms I did notice were a burning gear oil smell on park up. This is because a drip would hit the exhaust when driving, and well you know the rest.



Here it is, leaking

Leaking


The next step was getting parts. My buddy diagnosed it as a pinion seal leak so that’s what I bought - a differential pinion seal
https://www.lexuspartsdirect.ca/p/Lexus_2016_IS300-F-Sport-Sedan-35L-V6-AT/Differential-Pinion-Seal/94498017/9031143015.html

lexus also recommended I get a new nut for the flange. Cost about $5. After going through it, I would say the nut is not needed and can be reused. But for $5 I figured what the hell.

The steps are:

1. remove the drive shaft. This is pretty straightforward. It’s on there pretty tight so my buddy had to hit it out. That being said, you need to hit it indirectly to avoid damaging it. My buddy is a tech and knows how to do this. You don’t just take a hammer to it. Before removing the drive shaft, you MUST mark how it’s coming off to ensure it goes back on in the same exact orientation. You will get driveline vibrations otherwise. This is crucial before taking it off. Once off, he cleaned the rust off it. He also greased it before putting it back up.

2. now you will face that $5 nut on the flange. This was a problem area as it was on TIGHT. The air gun couldn’t get it off even. The other issue is the flange spins so you need to keep it in place. My buddy used a pry bar against one of the aluminum bolts which he placed back to use; subsequently snapping the bolt. Toyota has a tool for this but we didn’t have it (he’s a tech for the German competitors lol). He found two bolts from another diff job and put those two in and used the pry bar against those to prevent the movement. Worked like a charm. Turns out the Toyota tool works basically the exact same way!! We even called his buddy at Toyota and he was surprised how tight this nut was. These repairs are so rare that his buddys dealer has one tech who has done not even a handful of these in 10 years. Now you can remove the flange. Also, the bolt is krimped to prevent it coming lose. You must unkrimp it before take it off (chisel and hammer). Don’t forget to rekrimp on the installation.

2. Now you see the seal. You have to pry it out and eventually it come out. It’s in there good! To install the new seal, he had a tool used to go against the seal as you hit it into place. The tool is used to hit the seal into place evenly without distorting the seal itself. Once the seal is in, you put back the flange, put on your new bolt (torque to 90 ft lbs), then reinstall the drive shaft according to the marks you made when taking it off.



Seal on the car before removal.

Seal after


this concludes the differential seal replacement. Read on for additional things that were done. For a video guide, I looked at a video of it being done on a Lexus lx or Toyota Land Cruiser. The process is the same

following the seal replacement, we replaced the front diff fluid with fresh Toyota 75w85LT fluid. I was questioning what oil to use in my last post and was given some great advice. Decided to go ahead and use this grade fluid. My buddy said worst case, I can just drain it out and put in one of the suggested fluids on my other thread if I notice anything weird. Because we were on a hoist, the front diff drain and fill was easy. On your driveway, filling will be a challenge. The fluid was black and had a putrid odour.

Also changed the rear fluid. Super easy to do. Fluid was very clean… so likely was done by the first owner who leased the car. DIY Dan has a good video on both front and rear for those who wish to see

also had some rear inner tire wear so I had him align the car. It was aligned by him 6mo ago and was still in spec from then to now. He adjusted the rear toe though so we will see.

All in all, here’s the damage:

If you’re doing the seal alone, the parts cost was $35cad. Labour from Toyota would see this job reach about $4-500 as it is 3hrs of book time but can be done in 1-1.5h. He charged me $200 for this alone originally

if you add in the drain and fills, oil costed me $40cad/quart x3 for the Toyota fluid. Labour would be maybe $300 for both from Toyota but includes whatever oil they use.

alignment is minimum $100 or more if you’re at the dealer.
So all I had done would cost about $1000-$1100cad.

I was fortunate to know my buddy, so I paid $250 in labour for everything. With parts, my total cost for the seal, drain and fill, and alignment was $420cad.

Gerf

Usually when doing a pinion seal replacement most people will try to reuse the original pinion nut because when the diff is set up that nut is set to a specific rotational torque to get the correct preload on the inner and outer pinion bearings.

The indented area on the nut will give you a good idea where to stop tightening, some will go a little past the original indentation, with a new nut if 90 Ft lbs on an previously crushed (crush sleeve) is too much and increases the preload on the bearings you could have a problem.
Was the 90 ft lbs the spec in the manual for doing this job?

datis250

Hey gerf,

so my friend said the same thing as you did. We consulted the manual which did in fact specify 90 ft lbs. this was verified by my buddy’s friend at Toyota who double checked using their access and said the same. Given how tight the nut was to begin with, 90 actually seems less. But yes we did reference the manual and followed the torque specs outlined there. The repair is still fresh so I will be following it for the next few weeks to see how things unfold. Hopefully all is well!

Gerf

Glad you got it fixed, nice to have a friend that's a wrench right.

datis250

haha that’s for sure! And a friend that fixes properly. Lots of people that can “fix” but don’t do things properly or to spec. I’m a little particular (as you might’ve been able to tell lmao)