E-locker swap. Longer shafts needed??? (1 Viewer)

[Toast]

Ok so about a month a @GRM informed me on a different thread that if a guy does an e-locker swap into a late 80s housing he needs longer shafts. So I drug out my spare housing, spare e locker diff and spare V6 diff. After comparing the two diffs I really see a difference between the two on the passenger side. The driver side is 1/4” narrower between the ring gear and carrier but I don’t think the splines are any shorter.... I don’t know... I searched and searched and SEARCHED for hours and hours and only found one other tiny hint in a YotaTech thread saying the same thing... the original spline contact length is about 1 1/4” on shafts that measured 24 5/8” from the seal riding ring. Just hoping to get this sorted out. Thanks!!!

 

[pappy]

When I installed an e-locker in my '85 I didn't need a longer shaft. When I installed an e-locker in the front of my FJ40 I did need a longer shaft on one side.

 

[gnob]

I was actually planning on tearing the e-locker apart i have downstairs to show the spider gear to shaft to housing relations.
I have an 85 and 86+ housing and shafts.

 

[KLF]

I've done MANY e-locker swaps, and this is the first time I've heard of any issue with needing longer axle shafts. I just re-used the old shafts, never had a problem.



Not saying it's not a thing. Sometimes it's just better being blissfully ignorant. I say put it together, see how it fits. Go from there.

 

[Toast]

Yea, I thought the exact same thing KLF but GRM said that you needed to the other day and it got me paranoid. As I said, the passenger side is identical but locker side looks a tiny bit different. If anything, you would only need a longer driver side but I don’t think that’s even necessary. I’m glad to hear more people haven’t had any issues.

 

[pappy]

Yea, I thought the exact same thing KLF but GRM said that you needed to the other day and it got me paranoid. As I said, the passenger side is identical but locker side looks a tiny bit different. If anything, you would only need a longer driver side but I don’t think that’s even necessary. I’m glad to hear more people haven’t had any issues.

On an FJ40, yes. On a mini? No.

 

[pappy]

And just to clarify, I believe the FJ40 shaft is actually the same length as stock, it just has longer splines on one side.

 

[chesshircat]

You don’t need longer shafts for the front. It is when you swap an Elocker into an ifs rear housing you need to be careful. There are two different length shafts for the ifs rear. The shorter won’t go far enough into the carrier on the ring side and can break it.

 

[Toast]

Ok! So this is what I’m looking for! What length shafts won’t work?? What length will? Is it just on ring side? My axles definitely engage my e locker but are you saying they won’t at all or just a small amount of spline depth? The stock shafts look to have 1 1/4” spine contact. How much do I have when running these shafts with an e-locker? How did you figure this out anyways??? THANK YOU

 

[toyotaboy80]

I've read some carnage threads about wrecking the spider gear. It's unclear what shafts/housings they were using. Seemed to be a lack of spline engagement issue. Search google for e locker longer shafts spider gear or something along those lines and you'll probably find the threads I've read in the past. I think the consensus was buddy wasn't running era correct shafts in the housing.

It's my understanding that if you take the same year housing/shafts and put an E-locker in it, there are/should be no issues. (Aside from the FJ40 thing... no idea about that)

79-85 axle length is different than 86-95. And I think 86-89 4runner and 86-88 pick ups had narrower/shorter axles than the 90-95 4runner and 89-95 pick ups. By about 1/4"/7mm a side. When I was measuring shafts, I measured from the outside of the axle wheel mounting flange(drum off) to the end of the splines. My measurements were 28 1/16 and 28 5/16.

The locker side spider splines start deeper in relation to the housing bearing face compared to the non-locker spider. I.e if the spline starts at 20" depth on the non-locker side, the spline starts at 20 1/4" depth on the e-locker carrier side. Those are arbitrary numbers, just trying to illustrate the relationship between sides. Shaft engagement can be checked by putting grease on the splines of the shaft then installing the shaft. Remove the shaft and see how far the grease was pushed.

If you want to get REALLY anal at this point... On both sides there is roughly 1/4"+ of unused spline in the spider. Find a "first gen IFS" housing and put 2nd gen IFS shafts in it. The shafts will penetrate that last 1/4" of the spider. If going that route I'd advise measuring and test fitting. Might need to shave a couple mm off the shaft given tolerances of everything involved.

Doing that will give you 100% spider engagement and is more of a neat trick/upgrade IMO rather than something that is necessarily required for the swap. in OEM form the diffs got sent with 1/4"+ shy of full spider engagement. Unless there is an engineering principal saying not to have 100% spline engagement, I'll view it as an upgrade.

Taking a 2nd gen IFS housing and putting 1st gen IFS shafts in the housing will not leave you with enough spline engagement. On either side. Locker or not...but especially with a locker. I reckon that is where the issue stemmed in first place.

 

[chesshircat]

I assume you are asking about the rear. I am in the process of installing a ifs width rock assault axle with elocker and I just went through all this. There is a thread on pirate where a dude broke the center section bc his axles didn’t have enough spline engagement, I don’t know what axles he was using and don’t have any more knowledge of this but I do have both lengths of ifs rear shafts, the shorter are from a truck I think, the longer are from a 94 4Runner. The 4Runner are about 1/4” longer and are what I am using. I posted a pic of my axles and a pic from the broken center section from the thread on pirate.

 

[SuperDuperCruizer]

I have a few pictures of the cable locking diff I retrofitted/installed in the front/rear ff axles of my BJ42 build thread. The clutch needs the extra length of splines cut to allow disengage. The inner axle itself is the same length regardless of the end being long splined vs. standard spline cut. I thought I read this modification for a mini truck requires a notch to be cut in the axle housing for the clutch to engage and disengage.

At least for the 60-series and maybe the 70-series, the inner axles were different only in spline machining for cable/e- lockers. You can run a long splined or short splined inner axle in a factory non-locking diff but that’s not the case for an e-locked/cable-locked diff. You’d never be able to disengage from the locked position.

 

[Toast]

Yes, referring to a rear axle swap. I took at 87-88 rear IFS housing and put an e-locker into it. To the best of my knowledge, I’m using the same year shafts. No issues so far but my truck is only on 33s and I only do mild to moderate wheeling. I’ve got too much time and money into this to ignore issues like this so I sincerely appreciate the help. I measured some shafts that I know came out of a 87 4Runner. I’m not sure the “proper” way to measure these but I started at the seal riding ring and came up with 24 5/8”. So if I am understanding correctly, I need only the drivers side (locker side) shaft and it needs to be out of a 4Runner or truck? Or should I just do both? I read somewhere that the 4Runner shafts won’t fit (too long). Also, are the 90-95 housings longer as well or just the shafts? I noticed that my shafts only drop in 1 1/4” on the splines leaving an additional 1/2” or so left. Thanks again for all the replies!

 

[chesshircat]

you probably have the shorter of the two in the picture i posted above. the longer comes from a 2nd gen 4runner, i don't know if the housing was longer, i tossed it long ago. The longer fits. I don't know if its worth the trouble tracking one of these axles down if you aren't wheeling it hard. most ifs rear elocker retrofits are probably using the shorter of the two. i wheel mine hard so i made sure i used the longer, i can't imagine your truck would have the torque to twist the center out without dual cases and large tires, but i don't know

 

[Toast]

I’m super weird about stuff like this though. Won’t be able to sleep at night lol. Are the 90s 4Runner and truck shafts the same or is the 4Runner longer? Gonna start looking for a set. Wondering if I just need to do the drivers side or both???

 

[chesshircat]

I’m super weird about stuff like this though. Won’t be able to sleep at night lol. Are the 90s 4Runner and truck shafts the same or is the 4Runner longer? Gonna start looking for a set. Wondering if I just need to do the drivers side or both???

I think it is only the early 90's 4runner, i just happened to have one in my toyota junk yard

 

[gnob]

So to play devils advocate here,
What are 79-85 and 90+ rigs supposed to do about the axle being too short?
I mean if its a problem in one, its a problem in all.
What am i supposed to do about my t100 shafts?

 

[chesshircat]

So to play devils advocate here,
What are 79-85 and 90+ rigs supposed to do about the axle being too short?
I mean if its a problem in one, its a problem in all.
What am i supposed to do about my t100 shafts?

Like i said, I don't know anything about it. I read it on pirate many moons ago, when i decided to convert my rear to elocker I already had the 1/4" longer axles so i'm using them. I don't know if it will amount to a hill of beans. For all I know, the dude on pirate was running 79-85 axles in an ifs housing with 3/8" spline engagement and an LS motor. When i saw this post I just offered the limited knowledge i have on the subject.

 

[gnob]

That thread on Pirate is the result of a bent axle, not the spiders fault. Look at the uneven wear.

 

[chesshircat]

That thread on Pirate is the result of a bent axle, not the spiders fault. Look at the uneven wear.

Could be, i'm covered either way