Installing the Turtle Racing Diff Saver and HD Drive cups.
February 3, 2009 by Baja Planet
Filed under Tutorials
Beefing up the rear drive train of your HPI Baja 5B is a necessary upgrade once you decide to increase the Horsepower over the stock engine. There has been many issues of the diff case warping, flexing, and separating due to the additional torque created by the massive horsepower of upgraded engines and pipes. Along with this issue, the dog bones need to be upgraded due to twisting, the drive cups and diff shafts will also start to flex and bend at the ends.
Turtle racing has addressed theses issues with two separate packages. This tutorial will cover the installation of both kits as well as the installation of the “Missing Bearing”
- Turtle Racing Billet Differential Case Saver Kit
- Turtle Racing Reinforced Axle Set for HPI Baja 5b
Parts needed:
Optional Items:
Step 1: Preform Brake Maintenance
Step 2: Removing the Baja differential
Step 3:
Once the case is separated, remove the gear. It just sits in the case but may stick due to the diff oil. I chose to remove the cross pin set screw before taking the gear out but it is not necessary (See the next step.) You can do it now or later.
Remove the screw securing the cross pin with a 3mm wrench. Its assembled using locktite and my be difficult to remove. Use a screwdriver placed in the diff shaft slots to aid in its removal.
Remove the case plug with a 3/32 wrench and slide the pin out through the hole. Keep an eye out for the little rubber O-ring. These parts are supplied in your New Turtle Racing package but if your like me you will want to save everything just encase.
Remove the cross pin from the side hole. I used a needle nose pliers to help.
Pull the diff shaft from the case.
Remove the outer bearing. You may need to apply GENTLE pressure from underneath with a screwdriver. Be careful doing so as not to damage the bearing. Just work it off a little at a time going around the bottom of the bearing little by little.
Using a pick remove the diff washer on the inside of the case along with the copper bushing under it.
Remove the remaining bearing and the O ring under it.
Now grab the 2nd diff half with the diff gear assembly in it.
Remove the diff gear assembly by simply pulling it out of the case with your fingers. If it comes apart, dont worry just set it aside on a paper towel.
Repeat the steps above on this diff half to strip it down.
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Now the fun part, lets put it all back together now.
Remove the aluminum housing from your new Turtle racing dif half. As you assemble them you can do both at the same time or one half at a time its up to you. There is no difference between the two halvs so just get busy.
Install the rubber bearing seal supplied in your Turtle kit into the case Make sure its seated. I like to lube up all O-rings and rubber gaskets before I install them. Use some diff lube. Im sure there is plenty of it all over the place by now. Just rub some on.
Install the bearing.
Install the outer bearing. Make sure both are properly seated all the way. Press them with your palms. You feel the outer bearing seat and my even hear a pop when it does.
On the inside of the diff install the supplied copper bushing.
Install the diff washer.
Slide one of the two shorter Turtle Racing diff shafts all the way into the dif half.
Install the cross pin from the side hole.
Install the setting screw to secure the pin. Use locktite on the screw. Make sure the pin is centered then tighten it good and tight. Use a screwdriver in the slots of the diff shaft to hold it so you can get the screw good and tight.
Use the Stainless steel case plug and rubber O-ring supplied with your Turtle Racing kit and install it into the side of the diff case. It needs to be seated tight but not so tight it blows out the O-ring seal.
Drop the gear onto the cross pin. If it doesn’t fully seat flat check the cross pin and make sure its centered properly.
Drop in 1/2 of the gear set and cage. It doesn’t have to be all in place. As long as it look something like this your fine.
Work the gears into place against the cage. Make sure the pin is centered and the notch is pointing up.
Drop the 3rd cage in.
Put the 4th cage and the 2nd gear set together like this.
Drop it in. Again, it doesn’t have to be all in place at this time.
Work the gears and the pin into place. The notch in the upper pin must be pointing down and fit into place with the notch in the lower pin that is facing up.. It should all line up and fall into place with a little work. There are other ways to do this but this method works for me.
Lubricate the gasket supplied in your Turtle Racing Kit and drop it into place. It should sit in the groove that goes around the lip on the case. Always us a new gasket when assembling your diff. Turtle Racing was kind enough to include an additional unit with the kit. You should have also received several additional gaskets with your 5B kit.
Fill the diff with the lube of your choice. Make sure to spin the gears to allow the lube to distribute evenly. Fill it up to the top of the cross pins.
Put the two diff halfs together. Make sure you align it so the case plugs are on the same position as shown in the photo.
You will see that one of the aluminum case halfs has notches in it. We will install the large gear onto this half.
Align the screw holes on the case with the holes on the gear.
Press fit the case inside the gear and make sure its seated. If its tight turn the case until you get the best fit. You have 4 chances. It may be a bit tight but it will slide on using hand pressure. Make sure it is fully seated. Take note in the photo of the gear side to install the housing onto.
Install the Turtle Racing housings over the plastic diff cases making sure the hole on the outer aluminum case is lined up with the Stainless steel plugs in the case. Study the photo.
Install the 4 supplied screws making sure you use loctite. Tighten them up in a cross pattern.
What a pretty site!! To bad no one will see such fine workmanship. Just grin knowing its installed.
At this point you can re-install the diff back into the gear box and screw the gear box back onto the chassis, or go to the next optional step of installing the “Missing Bearing”.
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Optional step
Installing the MISSING BEARING.
The next part is an optional step. We will install what is known as the “Missing Bearing”. There is debate as to whether this bearing is necessary or not. The way I see it, it can hurt. Where the input shaft enters the case there is a dust shield that seals dirt out of the diff case. Many believe that there should be a bearing in this spot to better support the shaft. Its obvious by design that a bearing should be here. You have just spent some hard earned money beefing up your diff and rear drive train, your sitting there with the case cracked open, what do you have to loose?
You will need to purchase this bearing as it does not come with the Baja5B from the factory.
(1) 12 X 24 X 6 Bearing can be purchased by clicking the link or it is included in our Full Bearing Kit By clicking this link.
We need to remove the input shaft from the case. Use a 5/64th hex wrench to take out the set pin from the brake hub.
Slide the brake hub off the shaft.
Slide the input shaft out of the case.
Using a needle nose pliers, squeeze the two tabs together on the dust shield retaining clip and pull the clip out.
Remove and clean the dust shield. Apply a small amount of heavy grease to the rubber on the shield. YOU MUST REINSTALL THE SHIELD.
Install the bearing into the case over the dust shield. Make sure it is seated firmly.
Now reinstall the input shaft and the the brake hub.
Drop the rest of the gears into the case.
Reassemble the two case halfs.
Mount the diffcase back into the chassis.
END OF MISSING BEARING INSTALLATION.
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Next we need to install the new Heavy duty Dog bones. The bones that came with your Turtle Racing kit are heavier then the stock units and have been modified to work with the kit and must be installed. The stock units will not properly work.
In this part of the tutorial, I have already reassembled the entire Baja.
A few of these steps will not be needed if you have just upgraded your diff and are putting everything back together.
First we will remove the screw that holds the cross pin. Using a 3mm hex, place it inside the hub until you feel it seat into the head of the screw. You may need to use a pick to clean out the hex head if its full of dirt. Use your wheel wrench to hold the hub if needed.
Once the screw is removed, Use the tip of your hex wrench to push the pin out. If its bent or to tight, use an awl and a small tap hammer.
Next using a 3mm hex wrench, we will remove the screw from the pivot ball.
Using your fingers, gently tug on the inner boot to remove it from the diff shaft. Be careful not to tear it.
Now do the same with the outer boot.
The drive axle should easily slide out. It helps to make sure its clean and free of dirt.
Apply some grease to one end of the dog bone.
Aliign the slots on the drive axle with the pins on the dog bone and slide them together. Once they are together, work the boot over the Axle shaft.
Slide the shaft fully into the hub. Work the boot all the way to the hub so it makes a good seal to keep the grease in and dirt out.
Apply grease to the inner end of the dog bone.
insert the inner end of the bone into the shaft. Do NOT seat the boot at this time.
Reattach the pivot ball to the hub carrier.
Now work the inner boot over the shaft making sure its tight against the diff.
Replete this process for the other side.
Go ahead and put everything back together using the steps listed above in the tutorial.
CONGRATULATIONS!!
You now have the strongest drive train available for the 5B. Your money and time has been well spent.
I would like to thank Turtle Racing for their time and effort on the development of this kit. They stop at nothing to produce the finest quality products available.
During the making of this guide we chose to use a Stainless Steel screw kit to replace the factory screws. Stainless Steel doesn’t rust and offers much better protection against the elements. I also have to say they look great.
We also chose to replace the bearings at the time of this guide.
In our shop we use only Blue Locktite jell stick. Its a lot less messy and can accurately be applied to the threads more so then liquid. Our biggest reason is that it doesn’t separate so there is no need to shake it up before every use.
