First Gen Tundra 3rd in 2nd Gen Tacoma 8.4 Housing

I'm thinking of getting this 3rd member if it fits my 2nd gen 8.4 housing (that's going on my first gen Tacoma - how do you like that lol) I know about Erik's 4x4 site and that an 8.4 is an 8.4 regardless of which truck it came out of, however I just want to verify with people that know what they're looking at. The third is out of an 05 Tundra (which only came with an 8.4 unless I'm mistaken?) and is set up with 4.56's and a Detroit Tru Trac. If anything is amiss that the trained eye can see, I'd like to hear about what it is. Thank you!





@gearcruncher @Speedytech7

 

I'll answer my one question:

According to ECGS the only thing that would have to be changed would be the pinion flange because the Tundra's is 66 x 66 mm and the Tacomas is 60 x 60 mm. They said I could either swap it with my Taco flange or redrill the existing flange. They said to be careful since the pinion flange is preloaded and talking with Justdifferentials.com the work to change pinion flanges the proper way that they did it sounded like a lot of work and a little over my pay grade. Decided I'll keep looking for a bolt on solution.

 

Swapping the pinion flanges is a bitch and half a regear job and you'd have to make sure they actually have the same spline count. It's true that the flange is preloaded but if you can properly secure it in a vice you can redrill the flange.

Depending on the price this seems like a great find and if it's what you want I would go for it.

 

Or make an adapter plate maybe? I know EcGS sells those but maybe not for your application. Should be within your pay grade if you're able to do the fab work required to use a gen 2 axle housing in a gen 1 Taco

 

There will be help with that lol.

If it's a bolt up thing I'm good to go, but the extra process that would be involved either through having a shop do the flange swap or me having to buy a new drill press (sold mine a while back) makes it go past the point of temptation leading me away from just getting an assembled third with a locker like my end goal really is - if it was a plug and play situation I'd go for it for sure - thanks for reinforcing that swapping the flange isn't a job for a caveman - it's interesting that never came up before in all my research.

 

Look the gen 1 & 2 tacos already use different drive shafts. My point is you already have to somehow adapt right there so I don't see how it would be a big deal to adapt to the Tundra diff flange (other than that is does bolt into the gen2 housing) instead of a Tacoma diff flange.

 

The third in the 2nd gen housing is toast - bearings wore out and maybe some gear damage so I have to replace the third anyway - I got the whole thing for $150. I can get a rebuilt 3rd with the proper flange and a locker (which I ultimately wanted anyway) from a couple websites.

 

I wouldn’t wanna be drilling out the pinion flange either.....f that

Big difference between adapting a 3rd and ghetto rigging. Pinion flange lol

Hold out for the ‘proper’ solution

 

How's that ghetto rigging. Ghetto rigging is building a house with tires, tarp and mud. The factory at some point drilled the flange also... if you do it correctly it will hold up fine especially with the little torque tacos have

 

You would have to get everything drilled perfectly and make sure the flange isn’t drilled off center. Unless OP has a drill press I wouldn’t even consider it.

 

Are the drive shafts and wheel bearings and brakes still good? Then $150 is a helluva deal.
But I get what you're wanting to do now. If you plan to keep your drive shaft and want something bolt-on you need a third from a 1995-2002 6lug Taco with no elocker. Unless you bought an elocker axle housing but I assume you know the difference

Edit: I believe 1995-2004 could also work. I know the pinion gear spline count changed for the 2003 model year but not sure about the drive shaft flange. Just sth for you to be mindful of.

 

Well yeah, the holes need to be where they need to be haha

 

We just clamp a flange with the pattern we want to the existing flange on the third member, rotate it a bit to make sure none of the holes are closer than 1" and then punch it. Then drill it. Anyone building crawlers with the early trucks has to deal with it cause 79-83 flanges are different from 84-94 and then 88-94 v6 are different from all of them. But all mount in same housings and use mostly same shafts.

So long story short, if the price is right then go for it. Its not anything difficult or unsafe. I have never seen a flange break and in my group we have guys on 44s still running little toy thirds.

Marlin and TG sell tripled drilled flanges with holes closer than 1" and havent had any failures.

 

. It's all good. If I had the tools I could do it with 99% confidence. Right now I'm not set up to do that kind of work.

To be fair the flange on third on my axle was redrilled by its previous owner. This was what it was on at the time:

 

Lol, before you buy anything have you put an alignment bar thru the housing to make sure it's still straight after all that abuse?

 

Lol If it was good enough for him at the time it'll be good enough for me. It's just temporary until I can get a fabbed housing and swap in the third I'm buying. He's the guy that built that truck and a stand up person.

 

For sure. Even a string with a nut on the end will let you eyball a housing for bends while you are standing in the Seller's driveway. Just stand it up on a flange and get a flashlight and see how the string hangs inside the housing, then flip it and do it again.

 

That's a spartan locker or lock right not a true trac. Notice it's only replaced the spider gears and not the whole carrier...

 

Thank you bro! The deal wasn't worth it based on the seller making it sound like it was easy to change the pinion flange. Based on that I felt there was significant evidence to cut bait and move on. I'm glad I did because the tru track was the only thing I'd consider until I have a selectable locker - driving at freeway speeds in LA going right up against retaining blocks and such leaves no room to hop with a locker popping on all of a sudden.

I don't know much of what I'm looking at when I look at diffs yet, but I'm sure I'll know a lot more after I swap in the front and rear!

 

Good Call, glad you were able to move on. The true trac is great btw, I've had 2 in other trucks. The only short coming is when lifting a tire. No better way to learn then by doing!