I was told it was not good for the trany to use the engine to slow you down when going steep downhill. I use to put mine in first gear or second, not passing 3000 RPM, to slow me down on some steep Hill. It save on the hot brakes but:

Do you think it will damage my trany? Any experience with this is apreciated, I am going on a trip where theres is a lot of steep hill.

Thanks

 

Forgot to tell most every tranny I drive that it is hard on it...

 

I never had anybody tell me that. I see no problem with it. thats why they make exaust brakes and all for our trucks.

 

I have heard of such about the new trucks supposed ly having that issue, if so a testament of the new build quality...

 

By the way, mine is an E4OD automatic trans. I just phone the guy who installed a new trans in my truck and he told me using the tany is hard on the one way clutch. May be that is why I had to repplace mine? May be I gave it the last hit, but I had 170,000 miles on it.

Well, I do not know now, the brakes or the trany?

 

With a load on my f250 w/e40d I also downshift on the down hill runs. And, I have also wondered if this is too hard on tranny; however, I know the brakes would heat up if they were used to control speed (especially with TT attached). What other choice is there?

 

maybe should use in coordination? Automatics really weren't intended that way, it would be hard on First with the one way sprag your builder is talking about, but you should be able to have it slowed enough but that time. I can't see it taking any other gears out.

 

I use it in conjunction with the brakes, and I do not downshift once downhill. I shift in first or second before I start to go downhill.

I have a 3000 Lbs truck camper on mine, there is no brake on those of course.

On thing I did not know before is that you will burn your trany if you have your selector in second gear from start up. That trany will not do the first gear to start, it will start in second and stay in second.

I have a trans cooler but no gauge, probably a gauge would tell me if start to warm up too much.

 

it should not be too hard on trans but diesels don't have much retarding powre unless a compression or exhaust brake is installed.

 

oh yes they do, they have higher compression so they have better engine beaking witout the exhaust brakes, my 6.9 brakes quite well on it's own.

 

no, shorthair was correct. they have high compression, but no intake restriction, like a throttle plate. That's why gas engines slow down better.

 

Wel, I guess all the big semi's better quit simply downshifting, because not every truck out there has compression or exhaust brakes(they are not the same) to slow down, they are an option. Jacobs brakes, better known as jake brakes, use engine compression to slow down. At the last moment, they release compression, which is what makes the shock wave that can break windows. Both style engine brake require the compression to slow down, so if it were les effective, it wouldn't be used. They don't build higher compression due to these devices, they only control it's release.

 

semi's use a totally different type of retarder than we can use on our IDI's which changes the exhuast valve timing to achieve nearly as much brake hp as the engine devlops normally. IDI's valve train can not stand up to such us long term. we can use a exhuast pipe shutter valve and gain about 40-50% of our rated hp for aux braking without stressing our motors this can extend service brake life by 100% or more IF used properly.

 

but the point here is that a gas engine doesn't have the braking ability of our diesels, the throttle valve only creates vacuum, and yes, that's resistance, but engine compression will apply more resistance than engine vacuum. I have towed with both gas and diesels with manual trannies, and the diesel decels more than the gas. That would be due to engine braking force.

 

normally this is like preaching to the choir gas motors decelerate when you shut the throttle the butterfly valve closes and makes the motor work agianst a vacum which gives you deceleration. diesels are un throttled motors because they have no throttle butterfly to restrict air flow. if you doubt it go ride in a semi on a long 6% down grade with the jake brakes shut off when the brakes start burning and you kill all the sketters in a 4 county area you will find out just how little retarding a diesel has without an aux retarder be it cat's c-brake , jacobs , pac brake or any other style. remember the purpose of a semi's retarder is to keep the service barkes in good enough shape to save MY life when I realy need to jump hard on them.