yotarob2005

I did a little experiment with my 86 4runner last night to try and help me weight out the pro's and con's of adding a diff drop. My buddy had one laying around that came off of his second gen Tacoma so I figured (even thought the bolts are alittle too long) why not put it in and see for my self how much it helped the CV angles. I have read on this forum for several hours and not come to a clear conclusion. My 4runner currently has a set of 2" ball joint spacers and Downey torsion bars installed, with the t-bars set as LOW as they can go. My truck is used mostly offroad and has manual locking hubs so the CV's should only be turning when it is locked into 4x4 but I do feel like my CV angles are dangerously steep. The purpose of this thread is to help me and others decide weather the positive aspects of the diff drop out wieght the negative's

For starters here is a pic of my drivers side CV angle BEFORE the diff drop.


Here is a pic of the CV angle AFTER the diff drop was installed


Here are the diff drop spacers installed. In this test the bolts where a little too long but I did put them in for proper alignment and left my jack under the diff holding the pucks in tight.




The before and after shots of the CV angles do show that the diff drop does decrease the CV angle a decent amount, but I guess the question is, is it enough to make that big of a difference in saving CV joints? My line of thinking is that it is not. Lets talk about the negative aspects of the diff drop. For starters I was able to confirm that lowering the front diff WILL certianly prevent me from installing an IFS brace like the SDORI one, which is something that I want to use in the future. It also puts the front drive shaft right in the way of any type of custom skid plate that I might try to install. Finally the diff drop increases the front drive shaft angle by the same amount that it lowers the CV angle, which is fine for most trucks, U-joints should be able to handle the increased angle just fine. In my case I plan on doing a 2" drive train lift in the near future which will also increase the drive shaft angle, and I am afraid the combination might be too much.

My conclusion is that unless somebody chimes in and talks me out of it, I am going to remove the diff drop. I can completely see the benifit of using one on a daily driven truch, especially one with auto locking hubs, I just don't think that it fits in my case. CV joints are not that expensive or hard to replace so I am going to take my chances. I hope this helps people considering a diff drop and all opinions are welcome.

mightymouse

iTrader: (6)

x2 for ya rob, I had a similar set up to yours and even had the torsions cranked a little. I considered the diff drop but wanted the brace more and had faith that my cv's would be fine. I had recently purchased toyota cv's from the dealer and new suspension components and was able to wheel the truck only three times before it met it's demise. Although my experience was unfortunately limited what little time i had with the set up i never needed the drop for the diff. Personally i think using a set of custom bumpstops to limit articulation where the cv's bind would be more conducive to them not breaking at extreme angles. That with a combination of quality parts will render the desired affect from ball joint spacers and a mid-travel ifs truck. The diff drop also as you mentioned puts the diff in harms way wich was a big no no for me when considering it. I figured i would rather replace cv's on the trail instead of the front diff cracking. Personally rob i think your truck is pretty much there minus a couple of components. Next for me if it was my truck would be skids and a brace for the ifs and wheel the snot out of it.
Aaron

waskillywabbit

iTrader: (-1)

Depends on the vehicle, suspension setup and what type of driving you do most. There is not one all inclusive definitive answer.

On my 86-95 IFS, I've never bothered. Post 96 I've always added one. Got one on my 08 Tundra now with 3" lift. It helps with my CV angles hopping curbs at the mall.

:wabbit2:

irab88

iTrader: (4)

sub'd. i wanna get some bj spacers to ease my t-bars back to where they were. if the diff drop doesn't change the cv angles that much, i may have just saved myself a few bucks.

also want to hear others' thoughts on this issue

edit: rob, looks like you're missing some shocks?

yotarob2005

Thanks Aaron, for the most part you got my plan nailed down, including wheeling the snot out of it.


Wabbit I agree with your comment completely. I don't want anyone to think that just because a diff drop is not for me that it is not right for them, and there intended purpose.


Good eye Ian, yes my shocks are missing. I am still not sure what direction I want to go with for shocks, debating on getting longer replacement shocks or making new upper shock mounts and getting longer shocks.

iamsuperbleeder

Yeah I'm going to go with the "it depends on the vehicle's suspension setup". It may not benefit some people at all, but it may be 100% necessary for some in order to keep the CV joints from binding.


off topic a little, but what's the deal on those tie rod ends? those things are epic!

RustBucket

iTrader: (1)

Also interested in those rod ends -- they look pretty stout!

I had a diff drop for a while (88 IFS, BJ's, stock t-bars) but hated that it prevented me from running a brace and put the u-joint at a goofy angle. I could feel slight vibes coming from it. I had originally installed it to prevent CV binding, but after rebooting some stock axles I found that binding was no longer an issue. One of the critical parts that was neglected on my old aftermarket CV's is a dimpled plate on the inside of the inner CV joint. The aftermarket ones were flat, so the extra flex provided with the BJ spacers caused interference with the tulip joint. No issues with the stockers though.

rattlewagon

Excellent thread.

My .02 is this: It you have ADD hubs where they will be turning all the time, go with the diff drop. If you have manual hubs, you don't need it.

yotarob2005

Bleeder and Bucket, you can read about the tie rod ends starting here in my build thread.
https://www.yotatech.com/forums/f199...l#post51537468

Thanks RE-RE, I wish I could have found a thread like this one...that is the reason I did the experiment and started the thread.

Thanks everyone for your opinions on the diff drop.

bobby_duce

just about to say the same thing. ive been back and forth but for me with manual hubs im only locked in 5-10% of the time so my cv will see very little extra wear. so losing 1" grond clearance isnt really worth it.

if you have ADD either diff drop or manual hubs!

vital22re

iTrader: (2)

I have a 1" drop and hate the vibes when in 4wd. I may try to just cut the spacers in half.

iamsuperbleeder

wow, those are beautiful! good job on those

yotarob2005

Thanks Bleeder.

Well, my mind is made up and the diff drop is getting the boot tonight when I get home.

RustBucket

iTrader: (1)

Glad you came to a conclusion!

I'm also glad I discovered your build thread. Very cool!!

ChefYota4x4

iTrader: (5)

Fhewwwwwwww! lol. Oh well, live and learn. Anyone need a Deluxe Diff drop Kit with sway drop kit included at a discount? hahaha. Actually, this is still in question for me, but I'm leaning toward sporting my lift and new BJ's, etc., etc., without the drop kit for now.

Great thread, and thanks for bringing it up for discussion, Rob.

I too like those ends, and am very interested.

Your rig is still one of my fav's for quite a few reasons.

Have a good one,

Mark

85toyman

iTrader: (2)

ok, I did the BJ spacers on my 4runner as well and have been farting around with the diff drop kit as well. I had a downey truss on the rear, but took it off to put the drop kit on. I don't see where's it really makes a difference either. If one lowered the front of the diff, then I could see where it might make a difference, but only lowering the rear end of the diff seems kinds stupid to me. I have been contiplating building a custom front cross member that keeps the cross member in the same location but loweres the front section of the 3rd member into the cross bar, and then building a custom rear cross member and putting skid plate under that kind of like the Bud Built skids. I have the metal, and started the process, but have not completed it yet.

Either way, If the new cross member doesn't work, I will pull the diff kit and put the downey rear cross bar back in. I perfer to have some protection from frame seperation rather then cv loss. We all eventually have CV's go out.

findley

85toyman

Where did you find the downey truss??

yotarob2005

You bring a good point about the angles, however since I had the luxury of actually being there my oppinion is not based on the photos. I still think the pics are a reasonably accurate example of what I saw....minimal change.

yotarob2005

Thanks for the compliments Mark, Even if you decide not to use the diff drop then you are going to want to keep the sway bar drop kit. I ditched my sway bar all together, but since yours is a DD I would keep it and use the drop kit.

irab88

iTrader: (4)

i haven't had my sway bar on for months, and it's my dd (100 miles a day). a 4runner might handle differently, but i do have a cap and slight lift, with no issues from not having a sway bar.

not saying you don't need it, just saying that i'm fine without it
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