hurley842002

Hello,

I'm going to install a v-6 third member with a detroit in it, into my 4cyl housing. I've heard that the companion flange for the v-6 and the 4cyl won't match up. My question is are the spline count for the v6 and 4cyl pinion the same? In other words, would I be able to swap the flange from the 4cyl third over to the v6. Thanks

Adam F

Yes, they are interchangeable.

Or, you can simply re-drill the holes to accept the pattern of your drive shaft.

B4Runner

I just put a 1991 (supposedly) V6 3rd member into my V6 1988 4Runner. The reason I say the 1991 3rd i just installed is "supposedly" V6 is because as I was just about to attach the drive-line to the 3rd, the flanges don't match up. The guts of both 3rd's look exactly the same, so maybe 89+ just had a smaller flange for V6?

And since you said the flanges are interchangable, can I swap them without having to take the 3rd member out. Looking at my old 3rd since I took it apart, I would think that I can just swap out the flanges while leaving the 3rd in. I just want to make sure though.

Thanks for help in advance! I'm stumped at this point and I was currently working on the truck until this setback.

kiyobrown

Can you guys take pics of this? I swapped in a v6 3rd from a 92 pickup into my 87 4Runner, and the pinion flange and driveshaft lined up. We then got a 94 4Runner v6 third, and put into an 87 pickup (truckfiend's rig), and still no problems.

And IIRC, you can't just swap pinion flanges. The pinion nut is staked for a certain backlash. Your spacing won't be right and the backlash could be wrong, and you will chew up gears and blow up your third.

So I would think drilling for new holes on the current pinion flange would be you best bet, unless you know how to measure for and adjust backlash.


EDIT*
http://www.gearinstalls.com/troy.htm

See this thread from Zuk's site. It appears the pinion flange had been removed and put back on, and retightened to whatever the PO thought was good and tight. And now if you look at where the gears hit, its not where its supposed to be. You are running this risk if you are not familiar with working on the internals of third members. I see some chipped teeth in their future, had they not got it serviced right.

toyNG

I switched a 94 v6 diff onto my 86 pickup and everything lined up well. If it doesn't, you can buy something like this http://trail-gear.com/toy-flanges.html

B4Runner

I'm holding the flange from my old 3rd compared to the 91 I just threw in.

kiyobrown

Wow, thanks for the pic!! Seriously thats the first time I have seen it. Heard about it a bunch, but never actually seen them not match up. Good luck!

B4Runner

What you said about the blowing up of the 3rd and backlash doesn't make sense to me. They are both 8" V6 4.10 3rd's. My old is 88, the new is 91, so no problem there.

Shouldn't the flanges just exchange. Adam F, up above, says they will. The crazy intense 4x4 guy I bought the 3rd from says they will. And, this universal flange at http://trail-gear.com/toy-flanges.html says it fits right in to provide all the common patters.

So I'm pretty sure that I can just swap them. No offense in me doubting you, you're just the only "No" I've gotten and it doesn't make sense to me. The only difference I think there is between the two flanges is the size of the flange itself, not the structure of it on the inside of the housing.

kiyobrown

No prob, let us know how it goes.

Those were just the things I found as I researched for myself about swapping gears and the possibility that the flange didn't match up.


And no offense taken. The question was there to bounce opinions and options off of folks right? Looks like thats what happened.

B4Runner

Haha. Very true. Well I'm going to be optimistic and tell myself that there is no reason that they cant just swap out, like Adam said. I'm already upset enough because I thought I was going to have this done 2 hours ago. So I really just want it to work. It's going to be depressing when it doesn't fit. But, optimism to just getting this done and being one step close to getting my truck on the road again tells me it will work.

kiyobrown

good point. It'll be nice to know you got that thing back on the road!

B4Runner

I just saw your edit and read through Zuk's blog. SinceTrail-Gear sells one flange for all, that means that it would fit onto either of my 3rd's; meaning that I can just swap them. And considering what Zuk said, I think if I'm careful to not move the pinion forward or back, I think I should be fine. Thanks for your help! I'll update again with good or bad news.

kiyobrown

sounds good. If its the same depth and you keep it in the same spot, I hope you get the good result.