Hey, I have an ihi 55j2 and the gearbox on one of the finals failed. I've tried fixing it before with new parts and clearly that didnt last long. I'm just going to replace the whole drive, probably going with a chinese supplier. In your experience, is it fine replacing just one drive vs both? The drives won't be a perfect match, as the drives on my machine right now have cycloidal gear boxes, where as the new ones have a planetary gearbox. It's about $2600 if I buy two final drives, or $1450 each bought separately.
Honestly without knowing and seeing the machine / condition of the machine its hard to give an answer here. On a well maintained machine with lower hours replacing one that failed and not the other would not be an issue. Flip side to this if your machine is older, higher hours and or has not had a good life prior to you I would dig into the other final to have a look. Checking the condition of the oil when drained and get a look at the gears checking for slack in bearings and such. If it were my machine and the gears on the new replacement were planetary vs cycloidal I would replace them both so that they matched and would not be any issue with tracking faster or slower from one another. Plus you wont have to deal with any more final issues for a long time. If one side is crapping out it is fairly good to think the other side has just as many hours on it and went through the same maintenance or lack thereof.