e-brake/auto trans revisited

[WBusa]

I want an e-brake in The Beast... we tow horses, and SW Pennsylvania can be mighty hilly.



So, I've read umpteen old threads on the topic of e-brakes on Rams with auto trans, but I'm no more informed than I was when I started. Opinions seem to range from "no problem" to "you'll need 60# valve springs" to "you'll need a new TC and VB," to "you need a TC lockup switch, to any/all combinations of the above, plus people disagreeing with all the above.



With some regret, I'm going to open the topic up for discussion again, to see if we can achieve something like a consensus. Given my vehicle's characteristics (see sig, and transmission/TC/VB are stock and work well; transmission cooler lines have just been replaced with the new flared fittings, no more quick-disconnects Oo. ) what do y'all think... can I get away with installing an e-brake (I'm looking at US Gear's) without trashing my transmission? I should probably add that unlike out West, we don't have miles-long grades around here... just hills. If I was conservative and just used it when really needed, on relatively short grades, might it be OK?

 

[RBratby]

the use of an exhaust brake on a stock trans can break a stock input shaft. you can use exhaust brakes on aftermarket transimssions with billet shafts.

 

[Joe G.]

I've used a Pacbrake on my '95 for over 180K miles. My transmission has a DTT VB and TC. I have a TST rebuild kit in it for clutches and seals. The rest of the hard parts are stock. I think you would really have to work at it to break an input shaft with an exhaust brake. My 32' travel trailer is not exactly light weight. If you use common sense you should be ok. I use mine all the time even just running around with no load. If you only use it once in a while it may coke up. The places I go with my travel trailer have plenty of steep long grades. Some of them are really crooked too. In fact, the road from my house has a part that has a 9% grade. I've gone down that using the exhaust brake with over two yards of crushed rock in the bed.

 

[WBusa]

I've used a Pacbrake on my '95 for over 180K miles.

Joe, do you have/use a TC lockup switch? Some have expressed the opinion that when your TC isn't locked up an e-brake won't deliver much stopping power?

 

[Joe G.]

Yes I do. If the TCC is not locked the engine drops to idle when you lift. No braking at all. Putting your hand out the window does about as much good as an exhaust brake without the TCC locked.

 

[ToolManTimTaylor]

the use of an exhaust brake on a stock trans can break a stock input shaft. you can use exhaust brakes on aftermarket transimssions with billet shafts.

The use of an exhaust brake on a stock trans will create ALOT of heat as the converter UNLOCKS when the foot is lifted off the go go pedal. There are products out there (DTT AND ATS AND BD) all make gadgetry to take the thinking of controling the transmission's functions to combat that. And as Joe pointed out (And I still chuckle) you could gain even more braking holding a pack of cigarettes in that hand out the window. Heat is #1 no no. HOWEVER SOME TRUCKS have broken shafts even with a stock trans and a lockup switch but that is few far and inbetween from what i can gather. I can brake down to just below 20 mph and it's the 3-2 downshift that makes ya wonder if the trans is still under the truck. The higher the RPM's the more efficient brakeing you will have too. Oh and they are GREAT warm up devices in the winter too Oo. Oo.

 

[Joe G.]

Tim,



The transmission is a 47RH with a fly weight governor. A lock up switch is the only practical way to go. No electronic boxes work on it like the 47RE. There are some gadgets that force an unlock on them, but that is not what he wants for an e-brake. You are certainly right about the heat build up going down a hill with the e-brake on with the TCC unlocked. Probably won't notice that because it will be going like a run away freight train.

 

[CarlJensen]

The PAC Brake comes with two butterfly valves, one with a hole for 30# valve springs and one without a hole for 60# valve springs. The hole limits backpressure to stop valve float and give the input shaft a break so it won't snap on you. You must have a lock up switch, mine has a switch that does a lockup, runs normal or prevents lockup. Easy to put in and all you need is a double throw, double pole switch from Radio Shack, or the like, store. The 30# valve spring plate gives less braking effect but will still slow you down fairly well. The 60# plate puts you at risk of snapping an input shaft if you let it shift while the TC is locked, not a good thing.

 

[Joe G.]

The 30# butterfly valve PacBrake does work better than I expected from all the posts on this forum and others. I have installed 60# valve springs and blocked the hole in the butterfly on mine. It is certainly not a good idea to let it shift with the TCC locked with a load on the engine. That can break something. If the VB is stock it will not kick down with the TCC locked. It will kick down with some aftermarket VBs like my DTT. That surprised me at first towing on I5. Lucky I didn't break anything. I do shift with the TCC locked if I'm not towing. It's kind of like clutchless shifting a manual and takes a little practice. I lift to allow the shift to OD and give it some fuel to shift out of OD. Shifting manually down to 2nd with it locked is NOT a good idea. My VB allows lockup in 2nd gear with the shift lever in 2. That works very nicely on steep very crooked grades when I'm towing my trailer. The Buckhorn Grade on SR299 just before Whiskeytown Lake is a good example of that. The manual lockup switch works very well, but you have to pay attention to what you are doing.



All this reminds me. If you have the stock 35# exhaust valve springs make sure you get an e-brake that will work with those or replace the springs with 60#. Otherwise you may get some valve float and bend a valve head.

 

[WBusa]

Thanks!

Hey, thank y'all very much for an informative and helpful discussion; I'm now much clearer on the issues. I'm clear now that until such time as I'm ready to replace the TC and VB and install a mystery switch, I don't get me no e-brake. Sigh. Since my transmission is behaving perfectly well, I don't see a TC/VB replacement in my future any time soon. Maybe I should just focus on more bombs so my transmission'll go belly-up faster :-laf