A4LD Center Support Mod - Drill hole

[XLTByAccident]

I'm finally putting my 1992 A4LD back together and I had to replace the #4 thrust washer to get the proper endplay. The new thrust washer is plastic instead of metal. The transmission shop that I got the washer from said that they can no longer get the metal one and have used plastic thrust washers with no problems. As a modification the ATSG update manual says you can drill a hole in the center support for better lubrication to the #4 thurst washer. I can't tell for sure, but it looks like if I drill at the location specified, I will cross through an internal fluid chamber allowing more fluid to reach the center support thrust washer. Anyone done this modification before? Thoughts or advice one way or the other.

 

[92exp4x4]

I'd say if its common rebuild practice, then go ahead with it. It also may be the only way the plastic washer will hold up. Just a thought. I have not rebuilt any trannys yet.

 

[XLTByAccident]

I did the modification. A couple of things to point out for anyone else considering to do the same. Once this modification is made, you probably can not do the torrington bearing upgrade to the end of the center support that Glacier991 did in his A4LD rebuild diary (a must read for anyone rebuilding this trany!). Also later A4LD tranys do not have this washer as they have the bearing. I think Ford did the bearning upgrade in 1993.

If you do a future rebuild and want to do the bearing upgrade, you throw away the washer. The extra fluid hole would then be un-restricted and there will be a loss of fluid and pressure not available for downstream components. It may not be a significant loss since the hole is small (.086"). Just a warning. Three other things to watch out for; 1) Use a drill press. The hole should end up in the middle of where the bushing sits on both side of the center support. You'll probably miss with a hand drill, 2) A .086" drill bit does not come in your standard drill box. It's not 5/64 or 3/32. (I think I pulled a 44 from the index), and 3) the plastic washer that I got had excess plastic on the back side of the washer from the mold. This added another .010" thickness to the washer which would have caused the washer to sit unevenly. Carefully remove the excess plastic from the backside of the washer.