We did this type of stuff at the Cat house all the time on all types of things, 988/990 differentials(huge), off highway trucks, wheel loaders, dozers, transmissions, but we never welded them. Always used a torch, but the components were so thick you couldn't hurt them anyhow. The only thing it didn't work on was a swing motor off a 375 excavator. We heated the raises and put in large press to get the pinion out, think it was a 100 ton press with cage. It ended up exploding!! The old guy working the press about pooped on himself!!! About a $2000 housing and $4000 pinion later we had it rebuilt!
We also used this to get the roller bearings off on shafts, axle shafts. Cut the cage for the rollers and the heat the race. Sometimes it would drop off, other times one of the mechanics had a blacksmiths hammer(?) had a big V wedge on one side. We'd heat the race red hot, another guy would set the v of the hammer on the red and whack it with another hammer. Move around the race a few places and the race would pop off normally. Most of the time though we had some large prybars and one guy on each side under the race, heat it with the torch and it would slide up with pressure.
We tried the weld method on a hydraulic hammer once at a different shop to get the bushings out of the case, that didn't work. Ended up sending it out to have the bushings pressed out and new installed. This hammer was huge though, we had to stand on an 8 foot ladder(without the bit in it) to get the hydraulic wrench on the 4-5 inch nuts in order to torque them to some amazing number.
Thanks for the suggestions Tommy, BUT...
We do custom gaurdrails/handrails on new homes and remodels, stairs, landings, fire escapes, structural shop pre-fab and field erection, truck/ladder/pipe/lumber/etc racks for pickups (used to do 200-300 per year, down to about 6 per year now), equipment repair & maint (light and heavy), proto type work, Alum, SS, production runs, steel sales, inspections-TPI & Special, and more.
We have GMAW (short and spray), FCAW (gas & self shielded), GTAW, & SMAW. I have an ironworker, bandsaw, drill press, torches, plasma, airarc, chopsaws, magdrill, and much more.
Specialized?? Don't think so. Is there still room to diversify? Probably. But, right now I think I am too diversified for the amount of available work. I spend enough time inspecting that I don't have time to keep things going properly at the shop. That's why I am working at selling the shop. I'd rather be strictly inspecting. I can concentrate on one area better.
Have a Great Day, Brent