I've changed the wheel without removing the turbo on two trucks. Impact gun on the lowest setting and a short blip did the trick. Both trucks are still running fine.

 

Noted. I hadn't heard of the guy before but it was one of the methods that other boards had linked to as an example. Made more sense than wrestling the turbo out just to change the wheel.

Not buying the 'lack of lubrication' argument. You experience the same lack of lubrication on a cold start. Only the turbo is spinning considerably faster at idle during that few seconds it takes for the oil pressure to come up. Especially with non-synthetic oils in colder climates which millions of trucks manage.

In my opinion, retailers advising against the practice is just good business sense. The less liability you retain with your product, the safer you will be. With how easy it is to mess up these kind of installs, you want to remove as many variables as possible. In their shoes, I would do the same thing.

 

I noticed no problems when I installed one in my 38R. I installed it while the turbo was on the bench since I was doing a replacement swap of a defective unit. I had the exhaust side housing off and held the turbine wheel wrapped with a rag. I was able to hand thread the new billet compressor wheel all the way down before torqueing it.

 

How long do you think it takes for oil pressure to come up after the engine starts? Remember the injectors are fired off of engine oil.

Besides, exhaust gasses tend to be a bit smoother at spool up than an impact wrench. I was talking about the impact breaking the surface tension of the oil with no other oil coming behind it to replenish, but everyone is free to do what they choose.

Some have used an impact with no issues, others have rebuilt or bought a new turbo after using an impact. Your turbo, your choice.