Front 7.5" Differential Rebuild Questions (4runner diff in Tundra with Tacoma axles)

smokeysevin

Observer
As the title says, I am finally about to drop the 2000 4runner 7.5 front diff into my Tundra to button up the 4wd swap.

I am picking up a pair of tundra inner cvs to connect to tacoma manual hub outers. That means that the inners should be standard for the axle. I am disabling the add system.

The carrier is out of a 7.5" supra and is a clutch type LSD and will have new yukon 4.56's added on install.

All this is to ask, what rebuild kit do I need to get this crap setup?

Thanks,

Sean
 

DaveInDenver

Middle Income Semi-Redneck
Do you mean just a standard build kit? I'm pretty sure all the 7.5" clamshell differentials are interchangeable. I'd call ECGS or Marlin personally.


 

smokeysevin

Observer
Do you mean just a standard build kit? I'm pretty sure all the 7.5" clamshell differentials are interchangeable. I'd call ECGS or Marlin personally.


I read somewhere (that I can't find now) that claimed that there were a few variants that used different carrier bearings. I am trying to figure out if that is the case now.

I will give them a ring though, both of them know yotas really well.

Sean

Sent from my LM-G710 using Tapatalk
 

99Yota

Observer
Just curious but have you checked to see if any of the later model Tundra front clamshell diffs bolt in with no/minor modification?

It might be possible to pick one up for a really reasonable price which is a notch or two in strength up from the 7.5"

Based on this article here, seems it is possible to run the 8" IFS diff found in 4th Gen 4Runners, GX470s, and FJs in a 3d Gen 4Runner which is your donor vehicle. So in my mind, the 8" may also be compatible with your application if the 3d Gen 4Runner front clamshell is compatible in your Tundra. Guess the big question is whether the stock 8" IFS CVs fit using stock width Tundra a arms.

If mine ever breaks, I will likely be doing the same as I have too much invested in shocks at this point to ditch IFS. I would add though that beefing up the 7.5 has been costly. I'm running lotus front axles as RCV stopped making them (or did when I was in the market for them) and an ARB locker. which strengthened the carrier. Now, my weak link is the ring gear assembly. ECGS will get my business as they set my locker up 100K miles ago.
 
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DaveInDenver

Middle Income Semi-Redneck
@99Yota - the front end Brian Ellinger (Front Range Offroad Fab, https://frontrangeoffroadfab.com/) is running wasn't bolt-in so yes it's "possible" to run a later 8" IFS diff (and I think he was even working on one based on a 9" diff on the latest Tundra) but that's because he fabricated a custom long travel RCV 30-spline front end around one. I'm not sure he ever started making a production version. Thing is for the work he went through to build that IFS it is easier and cheaper to just do a solid axle swap.
 
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smokeysevin

Observer
Just curious but have you checked to see if any of the later model Tundra front clamshell diffs bolt in with no/minor modification?

It might be possible to pick one up for a really reasonable price which is a notch or two in strength up from the 7.5"

Based on this article here, seems it is possible to run the 8" IFS diff found in 4th Gen 4Runners, GX470s, and FJs in a 3d Gen 4Runner which is your donor vehicle. So in my mind, the 8" may also be compatible with your application if the 3d Gen 4Runner front clamshell is compatible in your Tundra. Guess the big question is whether the stock 8" IFS CVs fit using stock width Tundra a arms.

If mine ever breaks, I will likely be doing the same as I have too much invested in shocks at this point to ditch IFS. I would add though that beefing up the 7.5 has been costly. I'm running lotus front axles as RCV stopped making them (or did when I was in the market for them) and an ARB locker. which strengthened the carrier. Now, my weak link is the ring gear assembly. ECGS will get my business as they set my locker up 100K miles ago.


I didn't look into it to be honest. Since I am using the manual locking hubs I figure that worst case I can unlock the hubs and keep it in 2wd and still get home.

I did end up buying the solid sleeve from ecgs when I bought the rebuild kit for peace of mind but given that I am running a limited slip rather than a locker and the fact that I don't have rocks to crawl anywhere near me I think the 7.5 will hold up okay... at least until the 35s go on. That will require a gear swap from the 4.56's I have now though so its a ways off.

Sean
 

DaveInDenver

Middle Income Semi-Redneck
I wouldn't worry, just don't get crazy and abuse it. I ran 4.7:1 t-case gears and 5.29 axle gears in my 1991 with the stock front 7.5" IFS (it wasn't a clamshell though) and it was still the CV axles that were the limit.
 
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99Yota

Observer
I didn't look into it to be honest. Since I am using the manual locking hubs I figure that worst case I can unlock the hubs and keep it in 2wd and still get home.

I did end up buying the solid sleeve from ecgs when I bought the rebuild kit for peace of mind but given that I am running a limited slip rather than a locker and the fact that I don't have rocks to crawl anywhere near me I think the 7.5 will hold up okay... at least until the 35s go on. That will require a gear swap from the 4.56's I have now though so its a ways off.

Sean
I agree with DaveinDenver's reply - it should last after all, 7.5" is the OEM spec but perhaps will less margin of safety when using the gas pedal to get over an obstacle.

The 7.5" IFS clamshell diff uses 27 spline axles and the 8" IFS clamshell diff uses a 30 spline axles- not sure about 'cup' strength but guessing the larger splines would also have larger corresponding 'cups' and therefor, stronger cv joints. https://www.lcengineering.com/LCTechPages/DIFFERENTIALTOYOTATECH.html

I don't have manual hubs so maybe I'm a little paranoid about breaking a cv joint especially as most places where I am likely to do this are close to 2k miles from home.
 

smokeysevin

Observer
Has anyone run into an issue down the road from using a crush sleeve on the pinion bearing in the front diff vs a solid spacer? I am getting ready to do my gear install and figured that since everything is apart now would be the time to do it. Using the crush sleeve has never been an issue for me in the rear diff but since I am swapping the truck over from 2wd to 4wd I can't comment on the front setup.

EDIT: Listed my old parts in the classifieds, if anyone wants them shoot me a message.

Sean
 
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I’ve heard from a few that solid is the way to go, that’s what I did for mine. Not sure why though. Super happy with the 4.88s on 35s, freeway RPMs are definitely up there though.
 

smokeysevin

Observer
I’ve heard from a few that solid is the way to go, that’s what I did for mine. Not sure why though. Super happy with the 4.88s on 35s, freeway RPMs are definitely up there though.

4.88s are the eventual plan but I am holding off until I build the new rear axle. Its cheap insurance to run the solid spacer. I will probably pick one up.

Sean
 

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