Ford 8in / 9in Ring and Pinion Gears Install. With Pinion Preload, Gear BackLash, Pinion Depth Tool

I was installing new ring and pinion gears into an 8in rearend, for a 1968 Ford Torino GT, and decided to film the 3.80 gear swap process. Its basically the same procedure for a 9 inch rearend. I did my best to do everything as good as possible, but I did make a couple mistakes that I talk about, and would do a couple things different the next time around. I talk about a lot of general gear swap info, show the pinion preload, doing gear backlash measurement, and the ring and pinion contact patterns. I used a pinion depth tool, and talk about the process. I did make a general instruction sheet for my self to help with the whole process that is basically the same steps as in the video. I will post it below. If you have any questions please leave a comment, and I will get back to you.

8in Reassembly Instructions with New Gear and Carrier

Starting with Carrier Prep

  1. Check to make sure all bearings and parts are the right size.
  2. Grind inside case to get rid of ruff areas and casting marks.
  3. Can use old bearing insert as a piece to press or drive new bearings onto carrier.
  4. Lube shaft with standard light weight oil before installing bearings.
  5. Install bearing onto carrier with press or hammer on. Sound changes when you’re done tapping bearing on carrier.
  6. Remember to double check gear ratio that it is a set.
  7. Also check gears for any problems or cracks… etc
  8. Can also see manufactures contact pattern on gears from testing for duplicating.
  9. Back of ring gear should be oil stoned before installation or at least check for burs.
  10. Make sure ring gear bolt holes are clean and free of all oil so locktite will work.
  11. Drop carrier down into ring gear with ring gear supported.
  12. Start with 4 bolts and keep the gap even
  13. Then draw ring gear on slowly with **minimal effort
  14. Once ring gear is seated, remove bolts and reinstall all bolts with locktite.
  15. Snug all bolts by hand first with star pattern.
  16. Star pattern torque all ring gear bolts starting at 25ftlb, then – 50ftlb, then – 65ftlb
  17. Then double check all ring gear bolts with max torque in circular pattern.

Next is prepping the pinion and pinion housing.

  1. Lube pinion shaft with standard light weight oil
  2. Install bearing on pinion with press or tap on with punch going side to side.
  3. Make sure to only contact the inner race of the bearing.
  4. Go till its fully seated and / or the sound changes.
  5. Next is to install races in the pinion carrier.
  6. Make sure to lube before installing races.
  7. Can use old bearing or race to use as a driver if no install tool is available.
  8. Next install crush sleeve on pinion gear.
  9. Then install housing over the pinion followed by last bearing.
  10. Install seal with sealer and nut with locktite.
  11. Tightening until no play then check for preload.
  12. Rotational preload in new bearings is 22-23inlb without seal, (with seal installed 25inlb *Recommended), old bearings 15inlb.
  13. Keep Tightening in small amounts till proper preload is reached, making sure not to go over, and checking often. If you over tighten then must start over with new crush sleeve.

Install pinion pilot bearing.

  1. Make sure to lube housing before installation.
  2. Bearing should fit about have way before driving in.
  3. Drive in with a socket or driver that is slightly smaller than o.d. of outer surface.
  4. When sound changes the bearing should be completely installed.
  5. Install retainer with teeth facing back towards you.
  6. Driver should only contact raised ring of retainer and not the tooth edge.
  7. Tap retainer into place gently.

Pinion depth and ring gear backlash start

  1. Start with a 15 thousands shim
  2. Install pinion housing with no o-ring and three bolts.
  3. Check for pinion depth. With idea of discrepancy in axle center line.

    *Measure race and dived by two for center line, then measure from main cap seat to actual bottom of race mount for the difference in the center line. Must deduct difference for real depth.

  4. Adjust shims if necessary to get correct depth.
  5. Next is to install ring gear carrier with steps below.
  6. Lube case and caps adjuster threads.
  7. Also lube carrier bearings.
  8. Install carrier with races.
  9. Put screw adjusters in and make sure they’re moving good.
  10. Test backlash by hand and move over carrier towards pinion with no caps still.
  11. Place to where there is little backlash then install carrier caps.
  12. Lube bolts and install caps to correct side.
  13. Cap should go from top with little effort.
  14. Snug the cap bolts and make sure that they adjust and thread easy.
  15. Next tighten the caps at 50% torque at 40ftlb.
  16. Remove pinion assembly to set ring gear carrier preload or case spread.
  17. Correct way is to use wiggle bar and dial indicator for 8 to 12 thousands spread.
  18. Can also do it by feel / eye with info below.
  19. Tighten one adjuster with other adjuster holding pressure.
  20. Continue to spin test after tightening some, go till no free spin. That is roughly zero lash.
  21. Then tighten to next notch on adjuster.
  22. Do spin test… It will still spin after release but for a very short time. That is good
  23. Next Reinstall pinion to set backlash.
  24. Install dial indicator and set to zero
  25. Make sure pinion does not move during test.
  26. Now move gear to check backlash.
  27. 8-12 thousands backlash is ok, double check manufacture paperwork as it may differ.
  28. Loosen the adjuster the direction you want to move to adjust backlash.
  29. Make sure to move adjusters the same amount on each side to maintain preload.
  30. Check backlash again and keep adjusting till right.
  31. Remember to keep zeroing gauge for measurements.
  32. When close do a final 80ftlb torque on caps to double check backlash.
  33. Then check backlash at 3 or 4 positions on ring gear for final check.
  34. Readings should not vary more than 1 thousand of an inch.
  35. If problem check back of ring gear for variation.
  36. Now check everything with marking compound.
  37. Put compound on drive side of gear on about 3-4 teeth.
  38. Put a little pressure on back of ring gear for better test.
  39. Run the gear for a few more cycles to let the compound even out.
  40. 3 thousands off can make a huge difference.
  41. If pattern is proper move forward
  42. Next Final install pinion
  43. Install o-ring and lube with lite film of grease.
  44. Put in till o-ring contacts, use bolts to draw in while alternating with little effort.
  45. Torque bolts to 35ftlb.
  46. Install carrier bearing adjuster locks with locktite and torque to 20ftlb.
  47. Install back in vehicle.
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