bktaco

Folks:

Does anyone have part numbers for the front and rear TTs for the 85 4runner (SFA)? It seems that I've seen a few different part numbers for the front in particular:

913A609 (two pinion) $436 rearendparts.com
913A612 (four pinion) $436 rearendparts.com
913A318 (?) $385?! performanceoffroadcenter.com

Looks like I have the 2-pinion (visual ID), but I think I have seen even more part numbers after logging many hours searching all over the net. I am getting saturated, so if anyone can provide positive ID on the part numbers, or recommend a bona fide source, I would greatly appreciate it. Thanks, bk.

4Crawler

iTrader: (3)

You could contact Eaton and find out for sure:
- http://www.eaton.com/EatonCom/Market...ctUs/index.htm

bktaco

Thanks Roger. I might give that a try tomorrow. I have a Summit Racing coupon for 20% off one item, which expires tomorrow. That would bring the cost for both units down to the lowest prices that I have seen elsewhere on the net, since i can avoid shipping at the Reno/Sparks retail store. I think I might just go get them so I can use the coupon, Summit is excellent about returns if i somehow get the wrong parts...

Yoda

http://www.eaton.com/ecm/groups/publ.../ct_128482.pdf

Numbers from the above document:

Front = 913A318

Rear = 913A348

They are different part numbers because the front has less bias loading to make it easier to steer

Have the vendor doublecheck the numbers before ordering

bktaco

Thanks David. I just got back from Summit. Most of the web references I saw seemed to centralize on 913A609 (front) and 913A610 (rear). So now I have these shipping this week. I will have to give Eaton a call tomorrow to confirm, just too many part numbers floating around out there (I counted at least 6)! I will report back with Eaton's response. I hope I have the right ones in process right now, I am really eager to get gears on these and have my truck together before the end of October.

turtle jim

Take a look at this.

www.discoweb.org/truetracgears/index.htm

Matt16

I'd be really tempted to put a second rear (pre loaded) Truetrac in the front as it might come closer to locking.

bktaco

Interesting comment Matt. TC made the same comment at the end of another recent thread https://www.yotatech.com/forums/f116...70/index2.html

I will have to look into that option. If the rear "locks" up better in the front, why did Eaton engineer a separate application for the front? I read a bit about TT on 4crawlers site - no mention of a rear truetrac working better in the front than a front model. If it does "lock up" better, there must also be a drawback. Any ideas what this would be?

Wardamneagle

Steering. The better it "locks up", the harder it will be to steer.

bktaco

OK folks, I got the word from Eaton this morning.

1) The current part numbers for 85 4Runner application are 913A609 (front) and 913A611 (rear).

2) The older part numbers (913A318, 913A348) are for older models for the same application. The newer models are constructed with steel body casings (versus what, i don't know), and have a three pinion internal versus a two pinion internal.

3) The application of a rear unit in the front is weaker than using a front unit in the front. The Eaton representative did not comment on which one "locks up" better in front, just that the front unit would be stronger in front. I should also note here that ZUK recommended getting the correct part (front) for the front install.

4Crawler

iTrader: (3)

I've only run a front TT in the front axle and I found it locked up just fine. Not sure what the exact differences are between the front and rear models. Have heard it may be due to having the front model set up to work best in reverse rotation.

bktaco

After much consideration, I have slapped down the cash for dual Truetracs and 4.56 gears. I will post up a review of the new drive train in 2 or 3 months after I get some mileage on city/highway/trail/snow. Therein, I will also include a review of ZUK and ronsmachiningservice. For now, time to get wrenching!

Oatmeal

It's not that the front has less bias loading, it's because the front unit is spinning in the opposite direction that the rear would so the helixes on the worm gears are reversed. Ie. if you put a rear unit up front it wouldn't be as effective and vice versa -----------Hans

bktaco

that makes a little more sense to me, especially after viewing Turtle Jim's link above regarding how to convert the rear to a front or vice versa...

Oatmeal

Wow, that's weird, I didn't even see that. I was going to post that same link last night but, for some reason I couldn't get it to work -----------Hans

Wardamneagle

I just received an email from Inchworm....elockers on sale for $869 (in 4.10, 4.30 or 4.56). It's not too late!




...just giving you a hard time. Good luck with the diffs. I spoke to Zuk a couple of times. I was very impressed.

bktaco

got the first 3rd back from ZUK today, truly a thing of beauty

Detroit Truetrac LSD ($392) , 4.56 Yukon gears and master kit ($250), labor and shipping was about $300 (note ZUKs rate came in well under the local "Pro" shop even with shipping). front and rear together ran me just under $1900.

gearing and traction together is expensive! i am building this truck specifically for 4-season daily driver and expedition/road trips. This year the 4runner pretty much replaced my tacoma.

Wardamneagle

Looks great. My 2 elockers cost a little less than that and I spent another $200 or so getting them wired (used FJZ80 ECU and switch, wire, connectors, etc.). Of course I did all the axle modifications myself.

You have gone a similar route to my initial thinking which was Detroit rear and Truetrac front with 4.56 regearing of my OEM diffs. I couldn't believe how much that was going to cost me!

Let us know how it drives when you get it all installed.