1st Mobtown Build: PostRunner

PostRunner-1

Introducing the PostRunner: Mobtown Offroad’s 1st Truck Build

Project: Convert 2014 Tacoma DCSB Prerunner to 4-Wheel Drive

NOTE: This is not a tutorial, but it will provide information that took us months of research to find.

Introduction to the “PostRunner”

We have gotten started on converting our  Prerunner to a full 4wd offroad machine. This is a rather large project that required many months of research. Our project truck is starting life as a  2014 Tacoma Prerunner with a 2.7L 4-cylinder, 4-speed automatic. The goal will be to keep the conversion as stock as possible while keeping costs under $2500.

The Big Three

The three main things necessary to convert our Prerunner to a “PostRunner” are a Front Differential, Transfer Case and 4wd Transmission. Let’s take a look at each of these items to see what our options are.

Front Differential

We could have dove head first and gone with a full SAS, but this is a budget build for the moment. Plus, we want to get on the trail as soon as possible and a full SAS would take much more time (maybe in the future we will tackle this). Instead, we found a front differential from a Regular Cab Tacoma on eBay for $300 shipped. The differential had relatively low miles (80,000) so we won’t tear it apart, but we will change the fluids. We will also need to clean it up and give it a nice coat of paint from the rattle can. There were some small, but important parts missing from the front different we bought. Most of the mounting brackets and hardware were not included so, after hours of searching part diagrams online, we ordered a box full of miscellaneous parts. See the parts sheet for the list of items we needed.

Transfer Case

There are two options for transfer cases when converting a Prerunner. The first option is the stock electronic shift box. The second is to upgrade to the stick shift version in the FJ Cruiser. While the FJ box tends to be stronger and more reliable, we went with the Tacoma electronic shift transfer case. We were able to find the stock Tacoma box for much cheaper and we did not want to cut up the floor at this time. We got the transfer case cheap enough that, in the future, we could sell and upgrade to the FJ transfer case without losing too much money on the deal. We found our transfer case from a junk yard for $250.
Note: The input shaft on the transfer case depends on whether it mated to a manual transmission or an automatic. So, be sure to get the appropriate one for your truck.

Transmission

For the transmission, we could have purchased a transmission from a 4×4 Tacoma. But given that our project truck has low miles, we decided to explore the option of retrofitting the existing transmission to work with a transfer case. After plenty of research, we learned there are only a couple of differences between the Prerunner and 4×4 transmissions. The key difference is the output shaft. There is a different, shorter output shaft for the 4×4 transmission. Luckily, the shorter shaft will work with the 4×4 transmission. The tail adapter is also different. This is a simple bolt on piece that is easy to change. The difficult part was finding one. Most junk yards sell them attached to transmissions. The final difference is a small gear that drives the speed sensor. It’s cheap, but vital to making everything work.
We will pull the transmission from the truck, but we will let a transmission professional do the swap. This is an area where you can save some money. We weren’t confident enough in tearing down the transmission to tackle this job, so we went the safe route.

Miscellaneous Parts

There are a host of other parts that are needed to complete this project. The remaining parts are mostly small brackets and bolts that may or may not come with the “Big Three”. However, a few larger parts are needed: Front and Rear Driveshafts, Splined 4×4 Hubs, and CV Axles. The front driveshaft can be found cheap at a junkyard. The rear driveshaft can be cut down to length since it will need to be shorter due to adding the transfer case. For the 4×4 hubs, I recommend getting them from TacomaWorld.com member nj636. They are brand new and fully assembled at a reasonable price. If you can find them cheaper at the junkyard, all the better. For CV axles, we decided to with Cardone HD axles. Many people only recommend the OEM CV axles, but we are on a budget. If these don’t last, we will be forced to upgrade at a later date. But for the price savings, we risked it. A full list of parts required can be found below:

PostRunner-2

Retrofitting the Transmission

As stated earlier, our transmission will be retrofitted with the parts necessary to bolt up a transfer case. I won’t go into get length about the process for removing the transmission since there are plenty of tutorials already. It’s fairly straight forward. Here is a link to the service manual instructions for removing the transmission.

Transfer Case
PostRunner-3
PostRunner-4
PostRunner-5
PostRunner-6
Unbolting Transmission
Getting close.
PostRunner-9
PostRunner-8
PostRunner-10
PostRunner-12
PostRunner-14