So, with delivery now just some weeks away (finally got my VIN and build date -thanks Deysha), I am attending to a few track prep accessories. Question - for those that know, is there anything special about our diff covers? Does anyone know if any of the standard 11-12 GT diff covers fit? I was looking for one with extra heat sinking and a drain plug.

 

The Boss has the GT500 finned aluminum diff cover. There are bosses for drain and fill plugs, but they are not drilled.

 

I'm going to replace mine with one with fill and drain plugs also. I plan to run a rear diff cooler down the road too so I want to swap it out. Not sure which one to go with though.

 

I don't know if my local speed shop is just looking to drum up a little additional business but... They recommended to remove the Diff cover for service because the lower hole does not drain completely and the bottom is where all the "Crap" will accumulate. Sounded like a sound assessment so I changed my mind about the Diff drain holes. Just a little food for thought.

 

I do like to open it up and look inside just to see what's going on, just in case.

However, wouldn't the fill plug be useful at the very least?

 

The show cars they ran through the car show circuit all had drain and fill plugs. Plus, Ford is rather specific about changing out the fluid for track days. Honestly disappointing, as including the plugs seems like a no-brainer.

 

No, they are correct. There is a "trough" in the pumpkin below that hole that can hold quite a bit of fluid. The only way to evacuate it is to remove the cover.

The bosses on the diff cover should only be drilled if you're intending on running a diff cooler setup.

 

There is nothing about this in the Boss supplement "Track Preparation" section.

Even in our race car, we only change the diff fluid like 1x/season unless the cover has to come off for some problem.

 

I'm assuming that without fill/drain holes, we should fill the diff by unscrewing a bolt at the top of the diff, and then just pay close attention to the amount of fluid added?

 

In the supplement at the back, where it discusses fluids and quantities, it states this quite clearly, in fact. Pg. 32, Footnote 2 states it should be changed first after your first hour of high-speed driving or track conditions, and every 12 hours of track conditions thereafter.

 

OIC.

 

If that is the case then yes, I did not know about that but have not stuck my head up there to look. I still feel it would be better to drill and plug it anyway, even if you remove the cover to drain. At the very least it would make less of a mess and easier to fill for sure.

 

Agreed - I do like to take the cover off for end of the year cleaning, by I generally do basic drains and fills and use magnetic drain plugs for ordinary track weekend changes. I was looking at the Ford Racing cover, which has extra girding and a drain plug, and I am leaning that way.

 

To fill the diff, there is a plug on the frontside of the pumpkin that comes out using a 3/8 extension. You want the fluid to be one inch below that hole. You can bend a zip tie to the proper length to create a makeshift dipstick. It is also HIGHLY recommended to pick up a hand pump to do the filling. They are about ten bucks at most auto stores.

 

Cool, thanks. This is what I was expecting.

 

I've used a long hose to allow me to pour from beside the car and above the rear wheel.

 

I've done that too, but due to the viscosity of the diff fluid, it takes a LONG time. Hand pump can do the whole fill in like 2-3 mins depending on how fast you can pump. There's a joke in there somewhere...

 

You're welcome!

Deysha

 

Are you guys removing or moving the panhard bar to pull the cover off? I'm about to do the diff oil change and also do you have to lift the car at all? It looks like I might be able to squeeze in there. I haven't made any ramps yet. In my 4x4 Ford truck I remove the spare and I can sit "Indian Style" right there to do the operation!

 

You will need to drop one of the PHB bolts to swing it out of the way; otherwise the diff cover will not be able to clear the ring gear. It's easiest to get at everything if you can get the rear of the car in the air, with the rear axle un-supported.