Brake Retarder vs. Pac-Brake

[Craig P.]

My coach came equipped with a brake retarder that basically downshifts the transmission to slow the coach. It doesn't use the exhaust like the Pac-Brake. It seems to do the trick 90% of the time, but there have been a few instances where I wish I had more braking. Have any of you with a similarly equipped coach switched over to a Pac-Brake?

Craig

[Craig P.]

My coach came equipped with a brake retarder that basically downshifts the transmission to slow the coach. It doesn't use the exhaust like the Pac-Brake. It seems to do the trick 90% of the time, but there have been a few instances where I wish I had more braking. Have any of you with a similarly equipped coach switched over to a Pac-Brake?

Craig

[hondo122]

Are you sure there is no exhaust brake? My '05 Discovery has one and the tranny downshifts also. Check your paperwork. I know mine has one as I've oiled it several times. They require service and could be hanging up. It's on the drivers side. Let me know if you find it.

[Digital Boy]

Is your "brake retarder" always on? Or is there a switch or button to activate it?

Your Allison is likely downshifting because it is programed to downshift when your Pac-Brake is activated. It is likely that you have one. Unlike a Jake-brake, Pac-Brakes are nearly silent. At least I can't make it out, even with my window open.

Check your engine compartment. Mine is accessed by raising the bed.

[Craig P.]

Thanks guys, I'll crawl underneath and check when I get home from work.

I have a rocker switch marked "Retarder", but was told by an "informed person" that it only downshifts the Allison. I wish now that I had checked personally before embarrassing myself with this post.

On a side note, I installed a BrakeSwitch shortly after I bought the coach, and really like it.

Craig

[hondo122]

Craig it's quite possible that it's hanging up. They sell pacbrake lube, a couple of drops per directions could help.

[Gary RVRoamer]

There is an optional "retarder" for the Allison transmission, but it does a lot more than just down shift. Downshifting doesn't do much when the engine has no inherent compression braking to start with, and diesels do not.

The Allison retarder is a fairly expensive option and not often seen on a Discovery or anything else in that price class. And it certainly is not standard on that chassis.

Checking the spec sheets on the Freightliner Custom Chassis web site, I see that the chassis on the 2005 Providence included an "exhaust brake". For full details on your chassis, see 2005 Providence Chassis Specs

I suspect your "informed person' is just plain ill-informed..

[Craig P.]

Ok, it's official, I'm an idiot.

I just inspected my exhaust system, and I do in fact have a Pac-Brake. Question, is there any special method to lubing this thing other than spraying the pivot points? I read in another forum that Pac-Brake lube or a synthetic spray called "Super-Lube" should be used. I bought some Super-Lube at Ace Hardware and sprayed all of the pivot points with the engine off. I tried to activate the Pac-Brake with the coach in my driveway, but I assume it won't work unless you're moving down the road.

[hondo122]

Craig, I think the pac brake lube is high temp. Regular spray will burn off. Just a couple of drops on the operating parts. Mike

[Craig P.]

Mike,

You got me thinking, so I looked at the Super-Lube can. It says that it can withstand temps up to 450 degrees. This didn't seem to be high enough. Concerned, I gave Pac-Brake Tech Support a call. They said Super-Lube is an authorized lubricant and that it will work just fine.

I almost forgot, are you able to get much lubricant on the Pac-Brake shaft? The tech support guy said to close the valve by hand and lube the shaft. I couldn't get the valve to move more than an inch or so because of the spring.