Extreme Automatics put the 2004R on the map in the automatic overdrive 4sp market. We have been building and modifying the 2004R for 14 years. We have the fastest most reliable 2004Rs in the industry. We are famous for the transmissions we have built for the Buick Grand National. We also build units for Street Rods, Hot Rods and many other applications. We build units from stock to 850HP.
Extreme Automatics developed a VB (valvebody) 5 years ago we call the BRC. This VB was developed on the Answermatic VB Machine to duplicate the performance of the much desired and expensive Grand National BR VB. We are the only company who can duplicate the BR VB. That allows us to sell our 2004Rs out the door with no core required. We also have 30+ GM BRF & CZ cores in stock for those who want to exchange their transmission for the real GM version.
Options BRF Requires Core Charge $450 Reverse Manual Valve Body $200 Deep Sheet Aluminum Pan W/Bottom feeder sump $295 Billet Pump Rotor Assembly $285 Billet Input Shaft $275 Billet OD Planet $325 Billet OD Ring Gear $185 Precision Lock Up Tube for Multi Disk $75 Electric Trans Brake $495 (pan is required) Manual Trans Brake $200 Metallic Fiber Clutches $225 2.57/1.57/1.00/.67 Gear Set $760
Options Manual Trans Brake $150 Electric Trans Brake $395 Reverse Manual Valve Body $200 2.57/1.57/1.00/.67 Gear Set $595
The Facts About 2004r Transbrakes
There are 2 basic models of transbrakes for the 2004R. Electric and Manual. We believe Extreme Automatics builds the best Transbrake for the 2004R. I am going to explain the different models and how they operate pros and cons and let you decide for yourself.
The Manual Trans Brake (Slapper Brake) We sell and install this brake. Basic operation is to pull the shift lever in to low (1st gear) to engage the transbrake. When the shifter is moved out of 1st typically by slapping the shifter the car launches and all shifts are then automatic. This brake in the beginning was believed to be much like a neutral drop. When I looked at the fluid path closely its nothing like that. The brake was designed to slowly bleed off the Low reverse clutches so they are held on for the hit to the tire. This is why we have not seen the low roller failures over the years. This brake is very dependable works like a charm. Pro - Easy to install, Reasonable price, Works on all VBs, Great for the weekend warrior Con - Its a little slow to release, You loose manual control of the 1-2 shift. I install and sell these Transbrakes. Great brake for light racing or just having some fun.
Electric Transbrake (version 1) We do not build this brake This Brake is a one line unit that will engage the transbrake from the Drive position and uses stock pan. I don't think these are sold anymore but not sure. This Transbrake is the worst of all the transbrakes. It does not hold the low/rev clutches on after the launch. This Brake will kill low roller in short order. Pros - Very fast release much like the pro 400 brakes, Can be removed Cons - increased direct clutch wear, broken low roller clutch, Must work for transmission to operate. Builder must install and will need transmission to do so, Internal mods to the trans are needed. This is a parts breaker stay away.
Electric Transbrake (version 2) We do not build this brake This is a one line Transbrake that can be used with stock pan. This brake requires the shifter to be in 1st gear when applied. Pro - Its works mostly without fail, Holds low rev clutch, Trans will operate if it does not work, Can be removed if needed. Cons - Slow release, increased direct clutch wear,T-brake feed line fails it will kill transmission, Builder must install and will need transmission to do so, Internal mods to the trans are needed.
Electric Transbrake (version 3) This is a 2 line transbrake. I personally built and designed this version in 1994. Variations of this design was also built by 3 other transmission company's over the years. This is the most common of the electric transbrakes still built by most today. Extreme Automatics no longer builds this transbrake. Pros - Fast release, Holds on low/rev clutch, Retains full automatic shifts, Dual feeds 3rd for good clutch life, Requires after market pan for better oil supply, Very Reliable when its right. Cons - Expensive to manufacture, Requires intricate machine work, Very hard to duplicate so mistakes can slip threw the cracks, Brake must work for transmission to operate, If feed line fails it will kill transmission, Increased possibility of band failure, Can not be reversed, Can only be installed by the builder, requires special separator plate, Can not be installed by end user, Can only be installed on some VBs, Builder must install and will need transmission to do so, Internal mods to the trans are needed.
Extreme Automatics (New Transbrake) The Only Pressure Release Transbrake for the 2004R. We spent many hours R&D to develop a transbrake with no down sides. We were looking for a transbrake that could be installed on any valvebody with consistent results. This transbrake can be installed with any valvebody, any shift kit and can be installed by the end user. Can Be used with the stock pan.
Pros - Fast release, Trans still retains full automatic function, Can be used dual feed or regular feed 3rd, Holds Low clutch to prevent low roller clutch failure, Can be installed by end user, Transmission will operate under all conditions even if brake or feed line fails, Transmission will not be damaged if feed line fails, Retains full automatics shifts, Can be installed on every single 2004R valvebody shift kit separator plate etc., Can be removed or reversed, No internals mods to the trans are required, Transmission does not need to be shipped to the builder for installation.