exhaust brake question?
I have never had an exhaust brake before, nor have I driven a truck with one, but I Just installed my ebrake and 60lb exhaust springs this weekend on my CTD auto(47RH). I put my own system together with a completely manual system. The factory units as I understand all have a feature built in that automatically disengages tte e brake when the accelerator is depressed. Like I said, I have a totally manual system where I use a momentary toggle switch on my shifter that locks up my convertor and also activates my brake at the same time. My question is, will it harm anything to have the engine at fast idle with the ebake on at the same time to accelerate warm ups in the cold mornings, or is it only safe to have the ebrake on while the accelerator pedal is not depresssed as the factory units are?

 

any pics and specs on the brake?? I'm looking at doing it too, and I have a 4" downpipe off the turbo as well.

 

I bought my ebrake off of ebay a few months back. It was an inline 4" unit from Cummins/Jacobs that I think was originally for a Top Kick or something with a 4" exhaust. It came only with the ebake with actuator, band clamps, gaskets and the air switch to control the actuator. I already had on board air and 4" exhaust, and it was CHEAP! $150.00, and it was brand new, so I figured it would be perfect. I just need to know now that I have it installed and wired if it would be ok to run my truck at fast idle( i have a fast idle cable) with the ebrake on to make truck warm up quicker or if it will harm the engine by doing this.

 

It's perfectly ok to use the exhaust brake at idle to help warm the engine up. On some engines this has been a standard feature. International did that on some of the T444E engines (and consequently the PowerStroke as well). Some larger Cummins (linehaul trucks) I've worked on do something similar as well.

I notice that you said the switch also locks the converter. You will want to make sure that the trans is in neutral at all times. leaving the converter locked when coming down to a stop is very hard on the clutch packs and one way clutches/spragues. You can turn a well built trans into a pile of pieces in the pan if you lock the TC in gear at low speeds. I would suggest not using the brake at road speeds less than 25 mph to prevent that.

 

What I did was wire in a seperate ebake toggle switch only for warm ups that is seperate from the momentary toggle I use when stopping. The warm up switch allows only the ebrake to engage without locking up the convertor. I did this by installing a diode in between the two switches so the current would not back feed to the lock up wire. When stopping, it grounds both the ebrake and lock up. But when I am warming up, it only grounds the ebake.

Are you saying that if I am going down a long steep hill in town at say 15-20 mph, it will not be safe to downshift to a lower gear, lock up the convertor and engage the ebrake to keep from building up speed?

 

Well, not exactly. What I'm saying is you do not want the converter locked up when you are trying to hold the truck back at very low speeds or at a stop light, at these low speeds the Tc would act like a manual trans clutch. You will have to get a feel for how the truck responds, but generally below about 25 mph it is not advisable to keep the converter locked. It also depends on how well built the internals are on the transmission. Is this a custom built, HD trans?

I've spent a lot of time driving as well as wrenching on trucks. I've driven heavily loaded trucks in the worst conditions on and off road. There is a fine line to be walked at low speeds between safe operation and abuse, IMO. At 15 MPh you would need to pay very, very close attention and unlock the converter ASAP when the load on the driveline starts to reverse (e.i. when the engine is trying to drive instead of the weight). I realize you are hauling a lot of weight, but at lower speeds the service brakes are still the best bet, if they are not enough than you just plain don't have big enough brakes and I would look into putting bigger brakes on. Hope this helps.

 

Thanks W900 for your thoughts and opinions. I have only driven the truck about 20 miles since I installed it. Like I originally said, this is a completely pieced together ebrake system that I put together myself. As you can see in my info, there wasn't a kit that fit my truck exactly, so I had to buy the individual parts and wire it all myself. The transmission has been built by my my local transmission shop with the normal upgrades, but I would have to go back and speak to him to find out exactly what all was done. I know that if I try to slow down with the tc locked, the truck will start to shutter,(which I know is BAD, so I don't let that happen), but I also tested it going down a hill like I decribed above about 10-15 mph, downshifted to get the rpms up around 2,000, and engaged the brake and all seemed fine and the brake was holding the truck back. Would it be reasonable to say that if the truck is not bucking and all seems well that I am not harming the trans. Will it tell me that I am being hard on the trans by bucking, or will it do damage without warning me? I thought everything was looking good until I got back on here and started reading about all of the horrible things that would happen to the trans under those conditions. Sine this is a put together system, I have no owners manual to go by, just my good friends here to help me out on it.

 

The factory kits use a microswitch on a bracket off the timing cover, the throttle lever hits the microswitch at idle and activates the brake. I'm sure you could rig a similar setup...