Transmission Brakes - Truckers' Trucking Forum | Message Board

nbman · **^ Top** #1 11.29.2007

Hi everyone, I've got a question about Transmission Breaks. Some of the more experienced guys in my neck of the woods (who are hauling wood) are saying that Transmission Breaks are the way to go . To be honest I did'nt want to look any dumber than I am so I just nodded and agreed . I dont have a clue why a Tranmission Break is better that an Engine Break or even if it is . Could someone please help me out here ? To add some prespective I'm talking about hauling wood down some very steep hills on slippery roads .

Thanks

myminpins · **^ Top** #2 11.29.2007

Quote:

Some automatic transmissions modified or designed specifically for drag racing may also incorporate a transmission brake, or "trans-brake," as part of a manual valve body. Activated by electrical solenoid control, a trans-brake simultaneously engages the first and reverse gears, locking the transmission and preventing the input shaft from turning. This allows the driver of the car to raise the engine rpm against the resistance of the torque converter, then launch the car by simply releasing the trans-brake switch.

That's all I could find. They're not referring to gearing down, using your transmission to brake your engine or something, are they?

nbman · **^ Top** #3 11.29.2007

From what I could understand it was a part(s) that replaced an engine break , and it seemed to do a better job but was a little more expensive . I'm not sure if it is an application that is exclusive to the logging industry.

wallbanger · **^ Top** #4 11.29.2007

Sorry MyMiniPins, just like the description said, a trans brake is used to launch a drag car (or a doorslammer w/ an auto trans, like a powerglide) when drag racing. It basically lets you bring the rpms up, without the car rolling so you can launch with the engine revving where it can make good power.
What exactly those guys are talking about is beyond me. I'm sure someone here can shed some light...

broncrider · **^ Top** #5 11.30.2007

are we talking about a brakesaver???

the system where presurized oil slows the enginge....if so its not a tranny brake....its an engine system that uses oil in a valve system in the bell housing

works off a small handle on the steering colum, its right by and looks like a johny bar

25(2)+2 · **^ Top** #6 12.08.2007

Quote:

Originally Posted by broncrider

are we talking about a brakesaver???

the system where presurized oil slows the enginge....if so its not a tranny brake....its an engine system that uses oil in a valve system in the bell housing

works off a small handle on the steering colum, its right by and looks like a johny bar

I'm guessing that's what was meant, it's pretty rare, almost like full locking tandem rear axles, and if memory serves, it is a product from Caterpillar, kind of a competitive product for the Jacob compression brake(Jake Brake) which was first developed for the Cummins. It works by pumping oil under pressure which absorbs horsepower(torque). Please correct any of this that is wrong if you know better, I heard it from a couple of guys in Laredo over two years ago. I have never seen a tractor so equipped.

Burky · **^ Top** #7 12.08.2007

I can;t find any info on them, but I remember that there was an electromagnetic retarder that was popular in logging circles. Basically, (off the cuff here) it was a magnet unit that encircled the driveshaft and put an electrical field into motion, using the resistance to slow the truck. If I remember right, they were rated at around 400 hp of braking force, which would be equal to a decent jake brake unit. And I seem to recall that they were referred to slang as a trans brake, though the correct term was magnetic retarder.

In basic terms, it would be similar to the principles of dynamic braking used on locomotives. I'll keep looking and see what I can find on it, if anything.

Found some info, Aussie in nature, but it describes the unit I was thinking of.

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25(2)+2 · **^ Top** #8 12.08.2007

I just ran a check on Brakesaver, it's on google.

broncrider · **^ Top** #9 12.08.2007

i have run a couple of trucks with the brakesaver...one was a heavy wrecker with a 3408 cat ( kind of dates it ) ....but between the brakesaver and the jakes it would stop that thing at a gross of 140k...just better have some room
i miss that 78 kw sometimes

you can still get one thru kw if you order the arctic heavyhual package

Brickman · **^ Top** #10 12.10.2007

Quote:

Originally Posted by broncrider

i have run a couple of trucks with the brakesaver...one was a heavy wrecker with a 3408 cat ( kind of dates it ) ....but between the brakesaver and the jakes it would stop that thing at a gross of 140k...just better have some room
i miss that 78 kw sometimes

you can still get one thru kw if you order the arctic heavyhual package

Donny's black beast W9 has it too.

Some one mentioned full locking rear ends being hard to come by any more. You just have to order them. When I was hauling crude our trucks, even the 08 I was driving had full lockers. Two switches, one was the standard axle lock we all know and the other one would lock the wheels on an axle. That one would release as soon as you shifted to high range.

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