AMC Eagle Den Forum

The Shop => Transmission Shop => Topic started by: 1981EagleSX4 on November 05, 2025, 07:15:25 PM

Title: Clutch Pressure Plate Bolts
Post by: 1981EagleSX4 on November 05, 2025, 07:15:25 PM
 :eagle: What specs do I need for the pressure plate bolts for the 4.2 inline-6? I'm currently swapping the auto trans for a manual t4 and I've got everything but these. Google keeps giving me different answers, but I trust you all know what they are.
Title: Re: Clutch Pressure Plate Bolts
Post by: AMC of Houston on November 05, 2025, 10:07:13 PM
According to the parts book, its J4004165.  The AMC standard parts manual says those are 3/8 x 16 thread; 0.810 long (not including the head), steel, and are Grade 8 with phosphate coating.
Title: Re: Clutch Pressure Plate Bolts
Post by: 1981EagleSX4 on November 07, 2025, 10:05:11 AM
Alright. What about the flywheel bolts? Google says ½-20×1 inch, but is that overall length or under head length? I read somewhere that someone pulled .750 UHL bolts out of the flywheel
Title: Re: Clutch Pressure Plate Bolts
Post by: AMC of Houston on November 07, 2025, 12:29:28 PM
Bolt measurements are always just the under-the-head length; at least they're supposed to be!

Flywheel bolts are J3170524; which the parts book says are 1/2 x 20 thread; 0.840 long (not including the head), steel, and are Grade 8 with oxide coating.
Title: Re: Clutch Pressure Plate Bolts
Post by: 1981EagleSX4 on November 07, 2025, 04:40:41 PM
Alright man. Thank you!
Title: Re: Clutch Pressure Plate Bolts
Post by: 1981EagleSX4 on November 07, 2025, 05:20:12 PM
Sorry to bother again, but no parts stores have a .840 inch long bolt. Only 1 inch. Would that be ok or would it screw everything up?
Title: Re: Clutch Pressure Plate Bolts
Post by: EagleSX4_5Speed on November 07, 2025, 05:49:10 PM
ARP sells a set of flywheel bolts for the Jeep 4.0 and they are the same size as the 4.2.

ARP Pro Series Flywheel Bolts 146-2801
Title: Re: Clutch Pressure Plate Bolts
Post by: AMC of Houston on November 07, 2025, 10:16:27 PM
ARP = good stuff.  But per your question; the extra length can only hurt things if they interfere with anything on the back of the block if/where they stick out past the crankshaft flange.