Are there any Ford 8.8 Detroit TrueTrac owners here?
There appears to be a common mode of "failure" where the stock/Tractech Grade 8 bolts holding the side caps onto the carrier body stretch over time and snap off.
The side caps (which are the bearing surfaces for the pinions) are then held in place by the carrier bearings/races so catastrophic failure isn't likely.
The reason why the bolts fail is still unclear but it's suspected that the pinions slamming against the caps frequently causes the cheap bolts to stretch over time and eventually snap off. I've seen some pics of the bolts posted on Corner-Carver and they do not appear to have sheared off. The bolt heads actually separated from the threaded portion OR the threaded portion has snapped off (clean snap, no shear).
The bolts are either:
3/8 x 16 tpi x 1.5" for driver side
3/8 x 16 tpi x 1" for passenger side
OR
3/8 x 24 tpi x 1.5" for driver side
3/8 x 24 tpi x 1" for passenger side
The "newer" models are supposed to use the fine threaded 3/8" bolts, but it's unclear as to what is a "newer" model.
Use Grade 8 minimum, partially threaded (do not get fully threaded bolts)
ARP bolts are recommended replacements and they have 170,000 psi min tensile strength, about the same as Grade 9 (which BTW is used for the ring gear bolts and carrier bearing caps from the factory... go figure!).
Unless I find other info to say otherwise:
recommended torque is 40 ft-lb, threadlocker use is recommended.
The more horsepower you have, the better your chances of snapping these bolts.
I'd avoid using Grade 8 in this application due to the type of application and what Ford chose to use in the rear end (Grade 9 bearing cap bolts, Grade 9 ring gear bolts).
There appears to be a common mode of "failure" where the stock/Tractech Grade 8 bolts holding the side caps onto the carrier body stretch over time and snap off.
The side caps (which are the bearing surfaces for the pinions) are then held in place by the carrier bearings/races so catastrophic failure isn't likely.
The reason why the bolts fail is still unclear but it's suspected that the pinions slamming against the caps frequently causes the cheap bolts to stretch over time and eventually snap off. I've seen some pics of the bolts posted on Corner-Carver and they do not appear to have sheared off. The bolt heads actually separated from the threaded portion OR the threaded portion has snapped off (clean snap, no shear).
The bolts are either:
3/8 x 16 tpi x 1.5" for driver side
3/8 x 16 tpi x 1" for passenger side
OR
3/8 x 24 tpi x 1.5" for driver side
3/8 x 24 tpi x 1" for passenger side
The "newer" models are supposed to use the fine threaded 3/8" bolts, but it's unclear as to what is a "newer" model.
Use Grade 8 minimum, partially threaded (do not get fully threaded bolts)
ARP bolts are recommended replacements and they have 170,000 psi min tensile strength, about the same as Grade 9 (which BTW is used for the ring gear bolts and carrier bearing caps from the factory... go figure!).
Unless I find other info to say otherwise:
recommended torque is 40 ft-lb, threadlocker use is recommended.
The more horsepower you have, the better your chances of snapping these bolts.
I'd avoid using Grade 8 in this application due to the type of application and what Ford chose to use in the rear end (Grade 9 bearing cap bolts, Grade 9 ring gear bolts).
