oldlugs Posted January 27, 2015 Report Share Posted January 27, 2015 Hi folks, I just picked up one of the finned aluminum diff covers, supposedly the type used on GT500 '13-'14 cars with Track Pack. I'm upgrading my '08 Bullitt, which came with the stamped steel cover, and would like to know what length bolts to use (guessing they're either 1-1/8" or 1-1/4"). Also, is there a reasonably priced Ford factory bolt available for the application, or should I just go with some ARP and Loctite 'em? Thanks for any help. Quote Link to comment Share on other sites More sharing options...
Robert M Posted January 27, 2015 Report Share Posted January 27, 2015 (edited) Hi folks, I just picked up one of the finned aluminum diff covers, supposedly the type used on GT500 '13-'14 cars with Track Pack. I'm upgrading my '08 Bullitt, which came with the stamped steel cover, and would like to know what length bolts to use (guessing they're either 1-1/8" or 1-1/4"). Also, is there a reasonably priced Ford factory bolt available for the application, or should I just go with some ARP and Loctite 'em? Thanks for any help. Here is what I have........................ As close as I could get to the bottom side of the captured washer with the bolt laying at an angle. Don't forget the vent (or a plug) in the top............. When I bought this cover it came with the bolts. The vent I had to research at Ford parts. R Edited January 27, 2015 by Robert M Quote Link to comment Share on other sites More sharing options...
oldlugs Posted January 27, 2015 Author Report Share Posted January 27, 2015 Thanks, Robert! Quote Link to comment Share on other sites More sharing options...
oldlugs Posted January 31, 2015 Author Report Share Posted January 31, 2015 Thanks again. It went on today with 1-1/4" long, stainless ARP hardware and blue threadlocker. BTW- for the vent I used a -4 AN fitting with one end turned on the lathe to take a piece of 5/16" fuel hose, then a small, cheap fuel filter to keep the dirt out. Weighs a tiny bit more than the rattle vent, but cost less than $5 - the AN fitting was a freebie. Quote Link to comment Share on other sites More sharing options...
Robert M Posted January 31, 2015 Report Share Posted January 31, 2015 (edited) Thanks again. It went on today with 1-1/4" long, stainless ARP hardware and blue threadlocker. BTW- for the vent I used a -4 AN fitting with one end turned on the lathe to take a piece of 5/16" fuel hose, then a small, cheap fuel filter to keep the dirt out. Weighs a tiny bit more than the rattle vent, but cost less than $5 - the AN fitting was a freebie. ^^^That looks nice, I like the ARP bolts! What is that green plug looking thing on the lower side of the cover in the picture? I don't think my cover has that. So tell me............I see black paint on the left axle tube (and maybe a "1800" assy. line marking replicated) to the cast iron center section, but the oem bare metal right side? Are you in the process of working across your 8.8 coating/protecting it? It looks good. R Edited January 31, 2015 by Robert M Quote Link to comment Share on other sites More sharing options...
ZEROED Posted January 31, 2015 Report Share Posted January 31, 2015 oldlugs, I really like the looks of those bolts. What is the ARP part number or the thread size? I would like to purchase some. Also, since the KR has the diff. expansion tank, how come you still need the vent on top of the cover? What is brand and part number of the adjustable panhard bar also? I love the color combo on your car. Thanks. Quote Link to comment Share on other sites More sharing options...
msb64 Posted January 31, 2015 Report Share Posted January 31, 2015 I was also looking into new bolts for my FRPP axle girdle, because it came with unplated allen head bolts. When looking into the stainless steel option, I came across repeated warnings against using stainless steel fasteners against or into aluminum. I am going to try the stainless allen key bolts, but use plated washers as a buffer between the stainless bolts and the aluminum cover. I currently have that same cover that you have on my diff, pretty sure that the green plug is where you can add a temperature sensor. I believe It goes into the cover fins, but does not actually reach into the inside where the oil is. Quote Link to comment Share on other sites More sharing options...
Robert M Posted January 31, 2015 Report Share Posted January 31, 2015 I was also looking into new bolts for my FRPP axle girdle, because it came with unplated allen head bolts. When looking into the stainless steel option, I came across repeated warnings against using stainless steel fasteners against or into aluminum. I am going to try the stainless allen key bolts, but use plated washers as a buffer between the stainless bolts and the aluminum cover. I currently have that same cover that you have on my diff, pretty sure that the green plug is where you can add a temperature sensor. I believe It goes into the cover fins, but does not actually reach into the inside where the oil is. You are right about the green plug. I do have that threaded hole, but no plug. I had not noticed it before. R Quote Link to comment Share on other sites More sharing options...
msb64 Posted January 31, 2015 Report Share Posted January 31, 2015 Here is one of the pdf I looked at regarding the interaction: https://www.fastenal.com/content/feds/pdf/Article%20-%20Corrosion.pdf The degree of corrosion may depend on the type of stainless steel and aluminum, but it is probably a good idea to take precautions. Hate to see the nice aluminum cover turn into a white festering mess Quote Link to comment Share on other sites More sharing options...
msb64 Posted January 31, 2015 Report Share Posted January 31, 2015 They probably put the green plastic plug in there to protect the threads. A sensor/temp gauge back there would probably be a good option on a track raced car. Quote Link to comment Share on other sites More sharing options...
oldlugs Posted February 1, 2015 Author Report Share Posted February 1, 2015 To answer a couple cuestions... I put the green plug in to keep the dirt out of the threads. It just pushes in and was something I'd kept in my tool box to cap brake lines with. This axle assy, while the same part # as the KR used, is actually in my '08 Bullitt. The Bullitt and KR shared the same factory 3.73 assy straight from Ford. Only difference was that SAI installed an aluminum cover (sourced from Explorer, then modified) on the KR, along with the KR's axle expansion tank. The bullitt came with neither the aluminum cover nor the expansion tank, and had only a rattle vent on the right axle tube. The 1800 paint was there from the factory and I guess was assembly line marking. I'm just letting the rear tubes rust for now; maybe I'll pull the assy and paint it in the future. Corrosion of the aluminum cover is something I hadn't considered. Thanks for that, I'll keep an eye on it. The bolts are a 300 series stainless. Maybe I'll pick up a spare cover, just in case. I don't think I'll have any issues for a long time, but I'll watch it now that I'm aware. Neither my Bullitt nor the KR are driven daily, and rarely in bad (wet) weather. Those ARP bolts are 5/16"-18 x 1.25" long. ARP # 612-1250. They come with stainless washers and in 5 bolts / washers per pack (need 2 packs). I got mine from Summit within a couple days. Quote Link to comment Share on other sites More sharing options...
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