I have a 1996 Bonneville SSEi, and am happy with it. It'* about 50,000 miles now. As far as I know, the superhcarger oil has never been changed. When I call the dealer service to ask how often it should be changed, one guy says every 15,000 miles, and another guy (the one who seems smart) says about every 40,000 to 50,000 miles.

1. Is a "flush" the same as a "change"? If "flush" is different than "change", should it be "flushed" or "changed"?

2. How often (in miles or years) should it be done?

3. Balllpark, how much would this procedure cost? It doesn't sound very hard.

The *really* annoying thing I found out (as a warning to others here) is that if you take your SSEi to almost any oil change place, they *do not* even check your supercharger oil level. Even when Pep Boys did their "deluxe" service on my bonneville, I asked them if they checked the supercharger oil level. The manager said, "No, we never touch that. It'* dealer service only." This was a shock to me, because all these places say they "check your fluid levels". Golly gee, I thought supercharger oil was a fluid. It sure isn't a gas or a solid. I guess they only check windshield fluid and other obvious things. I wonder what else they aren't checking when they "check everything".

Anyway, on a related topic, how often should the differential oil be changed/flushed/checked? I'm pretty sure that'* another thing they don't check when they "check all your fluid levels". I've lost my confidence now as to whether these guys are really doing their jobs anymore.

If you don't know when you did it last 50k is a good one, but after that 50k is a good interval... Wren should pop in here.

The '93 manual doesn't suggest changing it at all; it just says that it'* silicone-based, not shared with the engine oil, and is basically sealed for life.

'course, once it springs a leak, you have to replace it one way or another, and just because something is sealed for life doesn't mean that it wouldn't be a good idea to get in there and change it every 50K or so anyway.

So I wouldn't be too hard on Jiffy Lube-type places for not wanting to mess with it since they would need to have the right stuff on hand to put in it, plus know what they were doing in the first place (which is a bit of a challenge for some places ), so I would either let the dealer do it, or do it yourself with the instructions found here.

(15K intervals are needlessly low, though; I think the guy quoting 15K intervals at you just wanted a little extra money for his boat payments...)

Jiffy lube won't have the right oil, anyway. I change mine once a year, but I flush instead of simply change. I figure it likes being spoiled.

If you don't know when it was done last, do it now. Procedure is in Techinfo. You'll need to get the oil from a Pontiac Dealer. A Chevy dealer may have it now because of the SC MCSS.

The differential is lubed by the trans fluid. No seperate check for that.

What'* the difference between a flush and a change? I know I'm the ignorant one here, but I just don't know. Will a dealer charge about the same for either procedure?

When most people flush. The get all the fluid out they can. Then refill it, run the car for a day or two then change it again. Chances are the dealer wont do that for you unless you have it changed & pay. Then pay for them to change it again. Its is cake to do yourself. I did my dads Ultra and my SSEi in under an hour. The bottles are $8 each and all GM dealers carry it. I got mine at a chevy dealer in the early summer and the guy says it is a regular stock Item that they have had for years. The bottles were pretty dusty, so they were not just in.

Jay

I add oil every 10,000 miles and would recommend changing it out every 50,000.

http://www.bonnevilleclub.com/techinfo/?article=22

I guess strictly speaking, a "change" refers to draining the old fluid until nothing remains, then filling with new fluid; an oil change, for example.

A "flush" refers to circulating a flushing fluid under pressure; that is, dislodging the old fluid by pushing in new fluid, continuing until all the old fluid has been pushed out; a cooling system flush using a garden-hose connection to your heater hose, for example.

Some service places can do a transmission flush rather than a change: instead of just dropping the pan and dumping fluid (which leaves untouched whatever is sitting in the torque converter at the time), they'll hook up a flushing machine to the trans cooler lines, and push new fluid in until all the old fluid has come out the other side.

This is a good explanation, with that said you cant really do a sc flush but the closest thing to it would be change the oil then change it again?

Well, yeah, in the sense that you really don't have an "input" and "output" port to hook up to; the best you can do is drain it and refill (more than once, if you like).

Frankly I don't think you need to go nuts with multiple fluid changes; just do it right, once, and you should be good to go for another 50K.