r686st Posted May 20, 2013 Share Posted May 20, 2013 I have a 1991 Mack RD690S with camelback suspension. I'm having trouble finding the correct trunnion bushings. My old ones measure 8 inches and some change but Mack and the aftermarket can only fine 4 and 6 inch versions. I have what I believe is 38K rear ends. Does anyone have any ideas? Quote Link to comment Share on other sites More sharing options...
thomastractorsvc Posted May 21, 2013 Share Posted May 21, 2013 Take a picture of the axle assembly and springs and post it if you have 34/38k you will have a light torque rod, if they are 44k they will be heaver Quote Robert"I reject your reality and substitute my own." Link to comment Share on other sites More sharing options...
kscarbel Posted May 21, 2013 Share Posted May 21, 2013 Assuming you have 38 rears, is it an SS38 (rubber bushed trunnion) or SSB38 (bronze bushed trunnion)?If you have rubber, then you're being misled by the squeezed out distortion of the original dimensions. Don't go back with the Mack 10QK219P2 insulator. Upgrade to the Mack 10QK276 urethane insulator. The vastly improved service life is worth the addtional price. And always install the trunnion insulator with 20wt non-detergent oil, per the Mack service bulletin.You can also upgrade to urethane lower spring pads (10QK388) for significantly longer service life (The upper pads remain rubber).And don't forget to check the condition of your transverse torque rod. Quote Link to comment Share on other sites More sharing options...
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