Hello fellow EBers, picked up a 10 SHO for a DD. good shape, 117k miles. Its a PP and runs awesome.
As its has warmed up here in SC this spring, I have noticed after about 30 miles the rear diff is making some noise when turning. Sounds like a Ford 8.8 rear diff when the Trac locks limited slip clutches are failing. Only makes the low pitch growling noise when turning and up to operating temp, and noise is not consistant all the time. So, I can't find much info on this diff, other than how much a replacement costs. Is it serviceable? I can exchange the fluid. Does it require the Ford friction modifier?
Anyone know how the limited slip in it works? That info would be helpful.
Asked my preferred local Ford dealer yesterday about fluid change in the PTU, thay said its not possible. Makes you wonder about qualifications...the dealer wants $139 to identify the problem with the rear diff, lol. Parts guy couldn't tell me about the friction modifier... so I am coming here to the real experts.
This is my 4th Ford EB, had 3 F150's with the 3.5. Had great luck with them. Know a lot about 11's, 14's and now have a 17. Put over 300k total on these 3 trucks and never had anything serious with any. Service service, service, and they will last. Need a few mods on the 11's that Ford has corrected on the newer models. I see Ford has also added a PTU cooler on the new vehicles.
So fluid changes/flushes for all the essential items coming up on the SHO. but need to decide about the rear diff, also have a couple Mustangs and just spent a grand for new posi unit due to Trac Lock failure. Trying not to do that on the SHO. thanks for reading! any help would be appreciated.
Welcome to the forum.
As far as I know there is no limited slip differential in this vehicle (never read about it nor seen it any specs that mention it). Your noise could be a wheel hub, those start making noise when turning and the load changes.
You can either suck the oil out of the PTU and refill or do the drill and tap mod and add a drain nipple.
Rear dif is serviceable afaik.
Replace em all. Trans. PTU and Dif. See how the noise goes.
I'm on my 3rd RDU. 88k miles.
1st time had metal clicking and grinding when backing up and turning.
2nd time just 2k miles ago, started howling between 45-60 mph. Ford didn't identify it properly and wanted more labor charges to continue trying to isolate the problem. I took it my friends garage and within five minutes identified it.
Check the RDU fluid and see if there are metal shavings. You have to replace the whole unit if that's what it is.
I don't know with the PTU. I'm still on the original one somehow and haven't touched the fluid. I do have the PP version with the cooler but I'm running a decent amount of power mods and it's held up so far.
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Thanks for the info, going to pull the rear diff cover and take a look. And check the rear hubs while its up in the air. The PTU has leaked some at some point, doesn't look recent, it seems ok driving, fluid change this weekend.
Thanks again for the info all.
Quote from: rdmccrary on March 18, 2021, 07:19:11 AM
Thanks for the info, going to pull the rear diff cover and take a look. And check the rear hubs while its up in the air. The PTU has leaked some at some point, doesn't look recent, it seems ok driving, fluid change this weekend.
Thanks again for the info all.
If the PTU has been leaking check to see if it was at the 'port'. If it has been 'puking' as we call it out he port.. the unit is on the way out fast, get a new one on the shelf. last i recall ford now makes a revision-g of the ptu we use. It is supposed to handle idling better and have flow changes to better circulate the oil.
Greetings from Nebraska.
Service that PTU, there are threads on how to do it here. Not one of Fords best ideas making it a "lifetime" sealed unit.
Greg
@rdmccrary (https://www.ecoboostperformanceforum.com/index.php?action=profile;u=6394) updates? the RDU sounds like it is need of replacement. could be the gears or could be the viscous coupler (clutch part) at fault. the clutches control the amount of power transferred to the gears and axles.