Injector Cleaning, Differential/Transmission Service
I just got my 2004 Subaru Forester back from the dealer where I purchased a set of P215/60R16 (T speed rating) Pirelli P4 All Season tires, subject of another thread on this forum that helped me decide to buy new tires. The reason I purchased from the dealer was the price, yes lowest price. I got the set out the door for $419.19 including even the 7% NJ sales tax.
I figured, correctly, that the dealer is selling tires at low profit to get the cars in for an inspection which will "yield" lots of other work that should be done. Well, that's fine with me, I'm happy to hear what an experienced mechanic thinks the car needs. Among the accepted news was it needs new front disc brake pads... I may do that myself. To the point of the post subject (I did read some helpful threads on injector cleaners) the dealer shop also noted I had not had the car in for 30,000 mile service, notable of which is included (and not done by me already):
Fuel Induction Service, Transmission service, and differential (front and rear) service, and Throttle Plate Service.
The injectors is just a cleaning and I've had good luck getting 150,000+ miles out of a set of injectors by just adding a bottle of injector cleaner a couple of times a year. I also buy Shell gas often which is advertised to have really good injector cleaner (who knows?).
I have never changed fluids or oils in an automatic transmission or in differentials - is that a mistake? The service offered by the dealer includes a "Flush" which is stated to clean filters and screens. I think the differentials just get drained and refilled.
I also note a Throttle Plate Service, which I also wonder about - clean and service the plate and idle control valve to remove deposits... Never done that on past cars either.
I will check my owner manual again, but I don't think it calls for the above work in its recommended/required maintenance service.
I know people who do all the dealer service procedures, adding at least another $1,000 per 100,000 miles in preventive maintenance cost. These same people sometimes get 200,000+ miles out of their cars, there may be a relationship here.