RT C190P - Which axle do I have

[MikeK5117]

Hi all. Just bought a 2004 Chevy Roadtrek 190P.

Been reading and enjoying all the threads on suspension and drive train, as these seem they would be a weak point on these heavy vehicles.

I was lucky enough to get both the original order sheet as well as the owners manual for the RV and everything in it. The order sheet lists the rear end as a "Locking differential - 4.10 gear ratio". The owners manual says this means I should have 16000 GCWR.

Anything I need to look out for on this axle. Seems it should be the preferred choice in the factory setups, just wanting to make sure I am figuring this correctly.

Thanks, Mike.

[markopolo]

I'm not sure what the GCWR would be but maybe someone here will know.

You might want to decode the RPO codes: http://www.classbforum.com/forums/f5...oder-1748.html

- that will tell you if it also has the auxiliary coolers for transmission and oil.

You'll get slightly less MPG than the 3.73 but better towing and less upshifting for hills.

[MikeK5117]

Originally Posted by markopolo

I'm not sure what the GCWR would be but maybe someone here will know.

You might want to decode the RPO codes: http://www.classbforum.com/forums/f5...oder-1748.html

- that will tell you if it also has the auxiliary coolers for transmission and oil.

You'll get slightly less MPG than the 3.73 but better towing and less upshifting for hills.

Thanks thats a great resource, already ran my codes.

I have listed the following:

KC4 NG SYSTEM ENG OIL
KD1 NG SYSTEM TRANS, OIL

Despite the "NG" in front which I don't know what it stands for, are these the listings for the aux oil and tranny coolers?

Regarding the 4.10 rear end, my past experience on more standard pickups and SUV's is I don't notice the mpg difference but sure enjoy the better pull it gives me.

Thanks. Mike.

[markopolo]

You probably were able to confirm the 4.10 and heavy-duty locking rear differential as RPO codes GT5 & G80.

I also have KC4 & KD1 in my van's codes.
KC4 NG SYSTEM ENG OIL
KD1 NG SYSTEM TRANS, OIL

V14 & V16 are the auxiliary coolers on my van.

V14 R OIL, TRANSMISSION, AUX
V16 R OIL, ENGINE, AUX

I've seen V14 display like this on newer RT vans:

V14 - Transmission oil cooler, external

NG could some abbreviation / truncation of cooling.

[MikeK5117]

I also have the V14 code but not the V16.

Yes, I have both the GT5 and G80 codes for the rear end.

[MikeK5117]

Did a bit more googling and found this on the RPO Codes.com website.

KC4 : COOLING SYSTEM, HEAVY DUTY ENGINE OIL
KD1 : COOLING SYSTEM, TRANS OIL

So, looks like I have both those options as well.

Thanks again.

[booster]

Easiest is to just take off a rear wheel or just the center cap if the steel wheels, and look at the hub of the axle. If it is flush with the wheel center, you have the stock 9.75" semi-floating non locking axle. If the hub protrubes several inches through the wheel and has 6 big bolt heads on it, you have the optional 10.5", locking, full floater rear axle.

There will also be a stick on tag on the driver side of the axle housing facing rearword, just inside the springs perch. You can see it be just poking you head under while lying on the ground. If the axle is very rusty, it may be gone, though. There will be a model # on it, and 60s is stock 70s is the optional axle.

[MikeK5117]

Thanks Booster. The sticker was still there and surprisingly good shape for a 14 year old chassis. I have to find out from the previous owner how he kept the underside so clean, other than some road grime there is little to no rust or dirt.

Checked the Onan oil while I was there.

Anyways, here is what the sticker says.

Broadcast - UJ4 (whatever that is).
Ratio - 4110 (4.10?).
Plant - CBA.
Diff - L/S
Model - 70S

So seems I got lucky and this van is equipped with the optional axle.

Thanks again. Mike.

[booster]

Yes, you did hit it good on that one. That will be a Dana Super 70. 10.5" ring gear, full floating hubs, axle. It has substantially higher capacity than the rear tires have, so more window of load, and it also will run much cooler at the hubs than the standard axle.

You should also have a G80 RPO code on the sticker, which will indicate that it has a GM Govlock differential, which is a mechanical locker initiated by rpm difference of the wheels. Very safe because it won't engage at above about 20mph.

[BBQ]

.

Diff - L/S means Limited Slip?

[MikeK5117]

Booster, yes, I do have the G80 RPO code. Cool would never have known what that was.

I am really happy with this van, in addition to being very clean, the engine pulls really well, tranny shifts nice and smooth, and after 1000 miles since I picked it up the engine oil is still as clear as the glass of Crown and water I am drinking right now. Plus great to have both the oil and tranny coolers.

Called my local GM service and will likely be getting a full flush, filter and upgrade to Delco Dextron VI in the next couple of weeks, and likely get the diff serviced and full synthetic there too.

BBQ, yes, I assume L/S is for the limited slip.