[TowerTalk] Issue with new gearbox on HDX689

[Rich Hallman - N7TR]

I was hoping someone on the forum may have seen this problem regarding a gearbox replacement for an original (5000lb) HDX689.   My original gearbox that is a 381 series 60:1 Hub City started to leak oil from one of the bearing seals so I wanted to get a new one and have this one rebuilt.  I received a new one from Hub City and when I apply any load to the gearbox, the main input shaft gets REAL hard to turn. To the point where the 1 ½ hp washdown motor will stall.

I just ordered a second replacement from US Towers thinking the Hub City one had an issue....the US Tower gear box they sell for the 689 has the exact same problem.   I did test the old box and it's a 60:1 Model 381 as well...so I have no idea why the new two different boxes have the same problem....but the old box works fine with raising and lowering the tower.  Not sure if there was a special modification they did to the original gear box or not.  All gearboxes have been filled with Mobile One 634 Synthetic gear oil as recommended by Hub City.

Based on the above...if you have any thoughts...let me know.  This for me just doesn't seem to make any sense.  I already have a call into US Tower, but with my past conversations with them, they do not have much knowledge around the original HDX689 x Brace version vs the new z brace model, which design wise is very different.

Thanks...
Rich

Rich N7TR
ex KI3V, N3AMK, WB3JOV
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