Transmission and differential fluid change/upgrade.

[Jb350]

Hey guys, it was suggested that after my hpde weekend I change my different fluid and transfer fluid. Just wondering what everyone is using that has changed/upgraded

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[Jb350]

Not a peep??? Come on guys a little help here lol

 

[Bob Loblah]

I'm giving BG Products a try. Sold through Optimum Performance, they also have a wiring harness to activate the diff cooler pump for a complete fluid change.
www.mustang6g.com/forums/showthread.php?t=48706

 

[THX 138]

What aspect of the OEM fluids do you find to be deficient and in need of improvement?

 

[Sprintamx]

There is no need to change either transmission or differential fluid after one track event. None whatsoever. A complete waste.

Now, if you want to change to a different fluid for a specific reason--such as different friction modifiers and/or more heat capacity before thermal breakdown (shearing)--that may be a different story. But, you should only be doing that if there are specific characteristics that you're trying to change. This has been the basis of some discussions about changing out the OE spec fluid for other stuff, such as the "BG" formulation mentioned.

Otherwise, it's money down the waste drain. One event does not "wear out" the fluid.

 

[Jb350]

It's not because of just the one event, it was a whole weekend(first day green group, second day blue intermediate, total of 7.5 hours), and the fact that the car is new.similar to how one would change oil after break in. I was recommended to use 75/140 for the diff if I was going to continue tracking the car often. I'm not very knowledgeable about these things hence the reason I created this thread. I'm not "looking" to change the oem fluids unless there is a reason it would be beneficial for track use, so any advice would be appreciated.

 

[Jb350]

What aspect of the OEM fluids do you find to be deficient and in need of improvement?

I don't find them to be deficient in anyway lol. I'm simply asking if there is other options that will preserve the components and /or be beneficial to use if I'm tracking the car often. I'm changing the fluids regardless so this thread is to find out if the oem fluids are capable of sustaining extended lapping sessions, or is there something better I should use in their place.

 

[Sprintamx]

Slightly off topic, but which event organizer did you run with that provided 7.5 hours of track time over 2 days? That's awesome and pretty darn rare.

Again, you have not crossed a line and worn out your fluids. As for changing the weight and formulation, do some research first as to why you might or might not want to follow the suggestion you were given. I'm not saying that to be an ass, but if you're going to start down the track day rabbit hole, then you're going to need to be able evaluate the advice you get. You'll get a lot, and most folks will be absolutely sure they know best! Me included!

So, why is 75/140 the right blend for our GT350 diff? What's wrong with the OE weight blend? And so on.

My advice, since you asked, is that you're fine. Change the fluids 1x per year at the start of the track season if you track the car 1x or 2x per month. If you track more often, then maybe a more aggressive change schedule. If you believe after research that the OE fluid is sub-par, then by all means swap it with something "better", but you still won't need to change more frequently.

Other folks will undoubtedly tell you to change more frequently, and will tell you that the OE fluid will break down quickly under high heat; particularly if you don't have coolers. Ask for their before and after use laboratory analysis.

Now, oil is a different story. Change that at least every 3 track events.

 

[xt6wagon]

The need to change fluids is massively reduced by the coolers. Overheating the fluids is the primary killer of said fluids in a performance application. A 2004 STi for example has no cooler for the transmission and can burn non synthetic in a single 1/4 mile pass thanks to the thermal load of 2 diffs and a lubrication pump on top of the normal gearbox heat.

In your GT350's case it would have dropped you into limp mode before you hit the temps that destroy fluids quickly.

 

[zombiekiller]

I'll say this much.. dont turn a single wrench until you take pictures of the entire underside of the car and validate that there is nothing amiss with the car.

Dont drain a drop of fluid, or even fart in the transmission's general direction.

 

[Jb350]

Slightly off topic, but which event organizer did you run with that provided 7.5 hours of track time over 2 days? That's awesome and pretty darn rare.

Again, you have not crossed a line and worn out your fluids. As for changing the weight and formulation, do some research first as to why you might or might not want to follow the suggestion you were given. I'm not saying that to be an ass, but if you're going to start down the track day rabbit hole, then you're going to need to be able evaluate the advice you get. You'll get a lot, and most folks will be absolutely sure they know best! Me included!

So, why is 75/140 the right blend for our GT350 diff? What's wrong with the OE weight blend? And so on.

My advice, since you asked, is that you're fine. Change the fluids 1x per year at the start of the track season if you track the car 1x or 2x per month. If you track more often, then maybe a more aggressive change schedule. If you believe after research that the OE fluid is sub-par, then by all means swap it with something "better", but you still won't need to change more frequently.

Other folks will undoubtedly tell you to change more frequently, and will tell you that the OE fluid will break down quickly under high heat; particularly if you don't have coolers. Ask for their before and after use laboratory analysis.

Now, oil is a different story. Change that at least every 3 track events.

I ran with Chin motorsports, at summit point.. from beginning to end it was a first class operation. Each day schedule -30 minute warmup/survey laps, (4)30 minute sessions for each group. And 1 hour open lapping session. From what everyone says they are a little pricey but I do not agree, you get what you pay for and I got my money's worth imo.....

The person who recommend 75/140 is the owner of tpc racing. They have several porsche cup cars they run in world challenge and IMSA classes. He drives one himself. They mainly work on porsche but also do suspension/track setup/prep for vetted, vipers, gtr, and several gt350s.

All the I trust his judgement, I always like to get other feedback, hence why I'm asking you all

 

[Optimum Performance]

Slightly off topic, but which event organizer did you run with that provided 7.5 hours of track time over 2 days? That's awesome and pretty darn rare.

Again, you have not crossed a line and worn out your fluids. As for changing the weight and formulation, do some research first as to why you might or might not want to follow the suggestion you were given. I'm not saying that to be an ass, but if you're going to start down the track day rabbit hole, then you're going to need to be able evaluate the advice you get. You'll get a lot, and most folks will be absolutely sure they know best! Me included!

So, why is 75/140 the right blend for our GT350 diff? What's wrong with the OE weight blend? And so on.

My advice, since you asked, is that you're fine. Change the fluids 1x per year at the start of the track season if you track the car 1x or 2x per month. If you track more often, then maybe a more aggressive change schedule. If you believe after research that the OE fluid is sub-par, then by all means swap it with something "better", but you still won't need to change more frequently.

Other folks will undoubtedly tell you to change more frequently, and will tell you that the OE fluid will break down quickly under high heat; particularly if you don't have coolers. Ask for their before and after use laboratory analysis.

Now, oil is a different story. Change that at least every 3 track events.

Owners Manual States Rear Axle Fluid Changes after first hour and every 12 after that. Several 2016 3.73 GTs have had over temp warnings for the rear axles. Heavier weight oil appears to be the short term solution. There are plenty of threads about it in the Roadcourse section.

 

[Sprintamx]

Looks like I have some research to do: GT 350 owners are supposed to refresh their differential / rear transaxle fluid after the first hour of use, and ever 12 hours thereafter? Or, the factory recommendation is after 1 hour of continuous track use, and thereafter every 12 hours of continuous track use? That would seem to be race-condition maintenance.

 

[Jb350]

The manual definitely says perform trans/diff service before and after track use. I saw no need to do it before my track day, because I only had 4k miles. But definitely want to do it now after. Another question I have is that if I went with a different diff oil (mobil 1,Bg, motul) would I still have to add the friction modifier?

 

[Optimum Performance]

Looks like I have some research to do: GT 350 owners are supposed to refresh their differential / rear transaxle fluid after the first hour of use, and ever 12 hours thereafter? Or, the factory recommendation is after 1 hour of continuous track use, and thereafter every 12 hours of continuous track use? That would seem to be race-condition maintenance.

From The Shelby Supplement:
"BASE WARRANTY
The GT350 carries the same warranty as
other Ford Mustang models. This
information is covered in its entirety in the
warranty information.
Warranty service for the GT350 or any Ford
Performance vehicle can be obtained at
any Ford dealer nationwide.
We do not recommend modifying or racing
(for competition or time) Ford
Performance vehicles, as they are designed
and built to be driven as delivered from the
factory. The warranty information
discusses vehicle usage and the
installation of aftermarket parts and their
effect on warranty coverage.
In the event the vehicle is intended for track
use, and the loss of warranty coverage is
not a concern, Ford Performance
recommends the car is equipped with the
Track Pack.
Additionally, perform multi-point
inspection and the maintenance outlined
in the 150000 mile (240000 kilometer)
normal maintenance schedule of the
scheduled maintenance before and after
track use. See the vehicle service manual
for removal and installation procedures.
Replace with Genuine Ford and
Motorcraft® service parts as needed.
These modifications may not necessarily
protect your engine from damage in
competition conditions. Subjecting your
vehicle to competition conditions even
with these proposed modifications may
render repairs non-reimbursable under the
warranty."

150K Mile Service:
"Change manual transmission fluid.
Every 150,000 mi
(240,000 km) Change differential fluid.
Replace accessory drive belt(s)."

From The Standard Mustang Owners Manual:

"Using your vehicle on a dedicated road
course may result in degraded function
and failure of major systems such as the
engine, transmission and rear axle due to
the overheating of these systems. If you
intend to use your vehicle on a dedicated
road course, we suggest that you equip
your vehicle with racing-type coolers to
protect these three systems.
In addition, if the vehicle is subjected to
dedicated road course use, we recommend
the following vehicle durability
maintenance:
• Change your axle lubricant and friction
modifier after the initial (first) hour of
high-speed operation; thereafter
change the axle lubricant and friction
modifier every 12 hours (under these
conditions).
• Change your transmission oil after each
event where your vehicle is subjected
to individual on-track sessions
exceeding 15 minutes.
• Change your engine oil and filter after
each event.
Additionally, perform a multi-point
inspection on items specified in the
scheduled maintenance section of this
owner guide before and after dedicated
road course use. See General
Maintenance Information (page 344).
See the vehicle service manual for removal
and installation procedures. Replace with
Genuine Ford and Motorcraft™ service
parts as needed.
These actions may not necessarily protect
your powertrain from damage in dedicated
road course use. Subjecting your vehicle
to dedicated road course use even with
these proposed precautions may render
repairs non-reimbursable under the
warranty."

So the OP has received excellent advice from his instructor. On the GT rear end fluid takes a beating, transmission survives better but the Shelby transmission is getting a lot more heat through it due to power, rpm and the abilities of the car. Where a very good driver would have to be in a GT to make the heat levels the Shelby is subjected to, a beginner could likely do it in a Shelby because of the chassis's ability.

The Shelby uses the same rear axle and fluid viscosity as the GT, and they use a horrible Low Viscosity Automatic Transmission fluid in the Manual transmission. That's why we have Dedicated Shelby fluid kits and recommend a change to BG Syncro Shift II and 75W-140 Axle Fluid. ATF is not ideal for Manuals.

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