IEDLS and XC Center bearings: the unexpurgated story

I spent the day today replacing my sagging stock center bearing in my 2007 Access Cab, and several things came up that I thought I would share. I have read every thread I could find about using these alternative bearings, so I thought I was ready. Not quite.

First, both of these bearings, the actual bearing part, are .125 inches longer than the stock bearing. The seat on the drive shaft for the bearing is .5" and the bearing is .625. This means that the bearing is not fully supported on the shaft. Probably not a big deal, but it does also prevent the yoke from going fully onto the spline. The whole drive shaft becomes essentially .125 longer. Ideally, you could use a lathe to shorten the yoke spline to compensate. I did not know this going in, so I couldn't figure out why the splined yoke was not seating. I ended up pulling it all back off to get these measurements. The last problem resulting from this is that the special nut with the staked nose did not thread all the way on either. This made getting a proper stake difficult. It could also create an interference with the U-joint. I looked at the new nut that I got from Toyota, and it was even longer, by about .062". I decided to re-use the old nut and cut down the nose, so it would be flush with the end of the shaft. Proper staking is essential on this nut! This allowed for better staking, and eliminating any possibility of contacting the U-joint. There is a thin shim on the inboard side of the stock bearing. I would recommend not using it with these bearings, because it will just make the problem worse.

Second, the stock bearing has seals at both ends that ride on the drive shaft and the yoke. These seals prevent water from getting into the splined portion of the yoke and creating corrosion. The IEDLS and the XC do not have this seal. If you use these bearings make sure to use a generous amount of tenacious grease on the spline, or the next time you try to change a bearing, the yoke could be seized. Bear in mind that since these bearings do not seal on the seats provided, those sealing seats will also get corroded, making a return to a stock bearing in the future impossible.

Third, there is no indication on the new bearings as to which end goes to the front. I think they could probably go either way, but It seemed that they fit the best with the longer nose to the front of the vehicle.

Fourth, the spacer needed to put the new bearings in alignment with the stock bearings is 2.310". Mine was longer because I have spacers to tune my driveline angles. A stock replacement will require 10mm-1.25 x 75mm bolts (minimum).

I have both of these bearings here, and both make a good replacement for the stock bearing. I ended up using the IEDLS bearing because I think it should resist sagging longer than the rubber version. It is a lot more expensive though! Both are plenty firm enough. The stock bearing is not suited for the Tacoma. The soft pillow design of the rubber guarantees that it will sag in short order and hold the shaft off center. Mine was 1/4 inch low.

I never read these things in the threads I combed through. My driveline is stock, so it should be like all the others. Hopefully people will find this helpful. If I get time tomorrow, I'll get some pictures.

As a side note, I bought all new U-joints for this job, but honestly the old joints were just fine. I ended up greasing them and re-using them. I grease my joints every oil change, and that is why even after 170,000 miles of hauling, towing and wheeling, they are still good.

 

Awesome work and research! Thank you for sharing as I'll be using some of this for my own IEDLS install.

 

I just performed the swap on my truck and used your information to create a spacer for the new carrier bearing. I ended up with a spacer that was 2.55 inches long. Seemed to get rid of most of my vibrations. However, now I'm getting vibrations that will gradually get louder as I go faster after 40mph. Did you have any issues like this or know of anywhere to start looking? Thanks.

 

One place to check is the side to side alignment of the bearing. Many people neglect that and focus only on the down angles. I aligned mine by turning the grease zerks to point straight down. Then I tied a string to the pinion zerk and stretched it to the transfer case. Lay directly under the string and use it to move the center bearing into alignment. The factory bearing has slots to accomplish this. You may have to create slots in your spacer to get enough movement.

 

Any luck with the vibrations? I wonder if the vibes could be coming from the added stiffness of the new bearing assembly.