Just brought my `04 Intimidator. not happy with the plating peeling off the wheels. I know it`s old but after grinding the rims for new tires still got a slow leak. Looks like I got to do some more grinding. Lathe in shop not big enough to hold these rims. I`m just whining about it. Got a bunch of miles on it, planning for a trans replacement. Supposed to be a heavy duty trans, is that so?

 

I take it you've got corrosion in the bead area? That's too bad - hopefully it cleans up for ya!

As for the transmission, if you've got the supercharged 3800, then you've got the "heavy duty" transmission. Unfortunately, its really not much different than a standard 4t65:

-the differential / diff cover/ output shaft length/ passenger axle is different (but there have been people at 400+ whp on standard 4t65s, so its clearly not a weak spot)

-the overall 'gear ratio' is different. HD are 2.93 vs 3.29/etc with non HD models for monte carlos

-the HD converter is bigger / lower stall speed (at least on w bodies)

-there is one one internal bearing that's different as well, but its a pretty minor item


Unfortunately the HD label appears to just be a marketing thing - they're not really notable stronger than the standard transmission.

 

it`s the plating that wraps around the rim peeling...ground off as much as I could but not enough

 

I can`t find any forums on superchargers. looking for maintenance info, rebuilding, etc.

 

Unfortunately not many Monte Carlos came with them, so there isn't much discussion on here.

I can help though as Ive owned a few of them.

Maintenance:

You'll have to check your manual, but I suspect there's no oil replacement interval listed. My 99 GTP didn't mention it at all, but Ive heard other owners claim theirs noted a 100k interval for checking the level.

Certainly plenty of regular owners who drove the car its entire life on original oil. But of course auto enthusiasts tend to like to go above and beyond to avoid any potential issues. I personally think changing it every 50k is plenty - it just lubes the drive gears and snout bearings. The bearings also aren't known to fail.

To change it, most use a (clean) hand soap pump. You take out the plug on the snout, push the tube to the bottom of the hole and pump out the old. Then you refill with new through the same hole to the plug level. Takes about 1.5 bottles. Use AC delco / GM supercharger oil. Then you just put the plug back in.

By far the most important thing though is making sure to keep it full, especially if you find it low (indicating its leaking somewhere).


Rebuilding:

Depends what is wrong. If its worn out and the rotors are trashed, just stick it in the garbage can. Gen 3 M90s are a dime a dozen, so you're better off just getting another vs a full blown overhaul.

The main pieces:
-Coupler. This is by far the #1 failure mode. Its a plastic disk that connects the snout drive shaft to the rotor gears. Over time, the holes oval out and it can slap back and forth as the engine idles. Usually sounds like a rock tumbler at idle - its very obvious. ZZPerformance sells replacements. Its good to time this with an oil change as you have to pull the snout to get to it (which will dump all of the oil if you didn't already pump it out). Id be willing to bet that failure rate is near 100% on these once in the lifespan of every 3800.

-Snout stuff - bearings and end seal. Again ZZP sells replacements (along with a complete rebuilt snout if you'd rather just drop one in). As with the coupler, the snout must come off. The bearings should never fail as long as you keep the oil full. The problem is that many people never check the oil and it gets low from either an old snout seal (as these cars are all pretty old at this point) or from the case seal leaking. Theres only about 6oz in the snout, so it doesn't take much of a leak to drain it dry.

-Case bearings. This is the only other rebuild part I can think of. If you pull the whole blower, remove the snout, and pull the rotor pack out, you'll see two needle bearings that supported the opposite end of the blower. I don't know of a current source for these, but Im sure they're out there if needed. They're lubed for life with a dab of grease, but are a pain to remove (most drill behind them and force them out with grease). Ive never seen these actually fail though (and if they did, they probably tore up the end of the rotors too which would make the whole thing junk anyways).

 

thanks for the info. I have no idea what it looks like on the inside. I assumed there is some kind of seal on the rotors. just wondering if I was getting the boost I`m supposed to. Have not yet hooked up with any other owners. Oil was low when I got it. Found out it`s just synthetic gear oil.

 

Yes and no. If you're thinking the old school drag blower Teflon lip seal, its not that. The rotors are completely coated though to help with efficiency. That coating generally stays fairly well intact unless the car has been run without a filter or has had water injection run through the blower. If you do pull it to look though, don't expect it to be perfect - they usually have some minor damage to the coating here or there unless it's exceptionally low mileage. Whatever you do - don't clean it. Ive seen plenty of people go nuts with a scrubby to get carbon off and absolutely wreck the coating.

But realistically theres not much you can do about it anyways. There are places that recoat SC rotors in general, but for what they charge, you could buy a lifetime supply of replacement stock blowers. Ive never seen minor damage have any notable impact on boost anyways - we're not talking gaping holes here, just small gaps in coating that's otherwise intact everywhere else.

How much boost are you measuring? Stock has a fairly wide range depending on tolerance stack and weather. But generally its about 6-8 psig unless its exceptionally hot or cold out.

I will say though, if you are seeing very low boost (0-3 psig max) the issue is almost always the boost bypass valve / actuator. The valve is supposed to close under load - eliminating the air path between the front and bottom of the blower. If it gets stuck open, the outlet air can reciruclate back to the inlet which tanks boost.

The only other issue I've ever seen is belt slip. But for a belt to slip on a stock pulley, its either the wrong size belt or the tensioner is done for.

I've never seen normal minor coating wear have any notable impact on boost.

Yeah, exactly - makes it easy. The oem specified ac delco stuff is stocked at most dealers and even some aftermarket shops as some aftermarket blowers use it too. Helps its dirt cheap too.

I will say since you just got the car, I'd check the level at every oil change until you get a feel for how much its losing.

 

I don`t get positive read on boost until 2500/3000 rpms. Is this normal?

 

What throttle position? The BBV is vacuum controlled so its possible to get to that rpm with light throttle and no boost.

If youre going WOT from a dead stop and aren't getting into boost until 3k, then something is wrong.

When it hits boost, how much is it hitting? Are we talking it feels lazy across the board and only hits 1 or 2 psi max? Or are we talking a lag down low- but suddenly jumps from 0 to 7 psi at 3k and feels strong from there out?

Either way would likely be a BBV issue. Look at the little arm beneath the black cylinder of the BBV - is it immediately closing with a quick snap of hard throttle?

 

For reference, anytime I put the throttle down all the way im immediately in boost. Even from idle.