Running Through The Gears

Published in the June 2008 Issue June 2008 Build, PowerStroke

toolsBuilding power is getting really easy for many diesel owners. There are more than 20 different plug-n-play power modules and programmers on the market for people to choose from. These can add anywhere from 40 hp to 160 plus hp over the stock power levels. Then you add aftermarket intakes, exhaust systems and the plethora of other power and you have a daily driver that has 450-500 hp pretty easily.

When OEMs are designing vehicles and components, they design them with specific parameters in mind. Most times they aren't designing them so people can go out and almost double the horsepower of the engines. As a result, there are weak links in the powertrain that just cannot handle the additional power. While some may be able to get away without any problems, most people aren't that lucky.

Richard Bennett has been slowly building more and more power in his 2004 F250 and is getting to the point that he is worried about not being able to get home one day because he got on the throttle and broke something. Since his truck is currently sitting at 430 hp, his transmission is probably the next thing to break. So, after doing some research in the market, he came to the conclusion that only a couple of companies make upgrades for the 5R110 (Torqueshift) transmission. After calling around, he decided that Sun Coast Transmissions was the best option for him.

We called Ron Wolverton at Sun Coast Transmissions and asked him if he could walk us through the build process. Wolverton said no problem and explained that after each transmission is built, they dyno test them""which means hooking them up to a transmission dyno and load testing them. On the 5R110 and Allison transmissions, they have to install them into their test trucks and drive them to verify everything is working properly, since they are electronically controlled.

We did discuss when someone should change or address the transmission and Wolverton said, "The 5R110 starts having problems with more than 400 hp. We recommend anyone doing any type of competition, whether it is sled pulling or drag racing, to upgrade their transmission as one of the first modifications they start doing. Depending on what type of use the truck sees, that will determine whether you need a billet input shaft, shift kits and which torque converter to use."_ He continued, "We build all of our transmissions with better clutches than the factory uses, as well as modify specific parts within to ensure we can use more clutches where necessary."_


Bennett was concerned that by adding shift kits and modifying the transmission, he would lose the comfort of daily driving. He was also worried about it shifting hard and the transmission being overly too aggressive. After the new transmission was installed, he and I were quite surprised by how smooth the transmission shifts (after the computer relearned the shifts) and we both agree that the transmission shifts smoother now than before.

In addition to the shift quality, the truck seems to accelerate quicker. Ron Wolverton said that we might notice a difference because of the torque converter and he was right. We both would highly recommend anyone looking for an upgraded transmission, to contact Sun Coast.


step 1

1. Chris Wolverton starts the day off by pulling Bennett's truck onto the lift. He drains the fluid, unbolts everything and pulls the transmission.

step 2

2. Next the transmission is handed off to Terry Bailey. Bailey starts off by removing the output shaft assembly.

step 3

3. Bailey is then very careful to remove the output shaft seals. He says they are often overlooked

step 4

4. With the seals out, after a couple quick minutes, the transmission is apart and into the cleaner.

step 5

5. When the transmission parts are clean, Bailey inspects them and hands everything off to S.L. Parker. Parker makes sure that every piston in the transmission is lubed with transmission oil to help prevent binding.

step 6

6. He then assembles the housing output shaft and housing.

step 7

7. Once the output housing and shaft has been assembled and the gaskets have been installed, they are mounted.

step 8

8. Next, the low and reverse hub is installed.

step 9

9. The pins that hold the planetaries in tend to walk their way out. So Parker scores them on each side to ensure they cannot walk out.

step 10step 10step 10

10. The direct hub assembly is then put together and checked. Afterwards, it is set on top of the forward hub, then the intermediate gears are installed and the sun shell is mounted overtop of them.

step 11

11. With years of experience, Parker has found that a bent coat hanger works best for holding the assembly together while setting it into place.

step 12

12. The next step after the low planetary has been installed is the forward hub assembly.

step 13

13. After each hub assembly has been completed, Parker blows air into the oil passage to ensure the clutches push forward (engage) and checks the tolerances.

step 14

14. Next, the intermediate clutches are installed and the center support is set into place. There are two bolts that hold the center support to the case that are located in the lower section of the transmission (where the valve body is). Parker leaves these loose until the entire transmission has been assembled.

step 15

15. The overdrive hub, planetaries and coast drum are assembled.

step 16

16. Then the overdrive hub and coast drum are flipped upside down and installed. Next, the overdrive clutches are installed.

step 17

17. With the majority of the transmission assembled, the next item to modify is the pump assembly. Parker removes all of the bolts and pulls the pump apart.

step 18

18. With the pump apart, the converter clutch regulator valve spring and blow off valve are changed to make the transmission work better with the new assembly.

step 19

19. The next step is to insert the input shaft. Parker makes sure not to force it in, but instead turns it and shakes it to get the shaft to seat properly. Notice the markings on the overdrive housing. There is a difference between a diesel 5R110 and a gasoline.

step 20

20. The pump assembly is then bolted back together and Parker torques the bolts. Then, the pump is installed in the transmission.

step 21

21. Now that the transmission has been put together, it is time to modify the valve body. Parker starts by removing all of the solenoids and wiring.

step 22

22. The next step is to disassemble the valve body and throw away the gasket/filter.

step 23

23. With the pump installed, Parker torques the pump bolts.

step 24

24. With a new gasket/filter the valve body is reassembled. Parker switches out the EPC (Electronic Pressure Control) solenoid in lieu of Sun Coast's proprietary EPC and changes the direct solenoid out for the modified solenoid.

step 25

25. The valve body and the shift linkage is installed next. The hammer is for the two pins that hold the linkage together. Finally, the pan is mounted and the assembly is complete.

step 26

26. Wolverton fills the transmission. Since this unit had already been tested on a truck, it wasn't quite empty. So he added 10 quarts and checked the fluid. He then went for a test drive and ensured everything was working properly and rechecked the fluid. Remember, to check the transmission fluid, the vehicle must be running.

27. He then reinstalls everything.

28. With the transmission assembled, Wolverton fills the converter with transmission fluid and slides it into place.

Source Box:

Sun Coast Transmissions
(800) 868-0053

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