Complete 8.4 diff upgrade

Hello Forum,

I am looking at a complete 3rd member for my '08 DCSB Prerunner 4.0. It has an open diff so I am looking to add some traction that I can install myself. If I am correct, installing the complete diff just involves unbolting of the drive shaft, unbolting and sliding out the rear axles, & of course, removing the diff. Is this correct?

I do not have computer access so I can't post pics but do this:

Google: just differentials
click on: Toyota
click on: Custom 3rd members
click on: Toyota custom 3rd members
click on: 8.4 Rear, T100 , Tacoma 4x4 & Prerunner, Tundra, Sequoia
choose: gear ratio (3.73)
choose: solid or crush sleeve (solid)
choose: traction aid (Heavy Duty TRD Eaton LSD)
TOTAL: $1634.00.

Rather pricey but I don't have to pay someone to install it. Unless anyone has any other suggestions or recommendations. I think this is cheaper than an ARB and less extra gadgets. I know ARB is Top Dog but I have to pay someone to install that also.

Also, when you see the gear choices, not all of them have an extra charge. Is there a gear ratio that is reasonably close to the 3.73's that I can use with my 265/75r16 BFG A/T's or do I stick with the 3.73's?

Thanks for your help in advance!

 

Since your a prerunner I'd bump up to 4.10 or keep your 3.73 if you plan to keep your current tire size. If your going to a 33 and auto go 4.88 if stick you should be ok with 4.56.

 

Google "east coast gear supply". They sell assembled 3rds at the best prices and with the best warranty in the business hands down. They are highly regarded here.

 

It's like 1500 for a 3rd with an ARB from ECGS less shipping, but shipping isn't too bad. They overnighted me a whole 3rd for 200 bucks and ground shipping is WAY cheaper.

A compressor for the locker isn't too much either and ARB makes the wiring and plumbing super easy. Unless you want the LSD for the street.

 

I do mostly street, about 10% off-road. I have used my truck in soft sand and mud about 7 times this year. I only got stuck once, in a soft sand trail that was only for ATV's.

Basically, I want something that can help me a little in both situations
EX:
pulling a boat out of a wet ramp,
light off-roading.

I have a customer with an '09 & Tacoma ('09's and newer have the brake assist LSD). It's a company truck and he has to do repairs to powerlines which means that he drives through dirt and sand almost daily. He used to have an open diff'd '06. He says the difference in traction is day and night. I've read that the TRD LSD is better than the electronic one so I assume that I will notice the difference. Let me know what you think.

I understand that Lockers are the best guaranteed traction but LSD has to be an improvement over open diff.

 

Oh, as for tires, I want to eventually buy a set of 17" FJ Cruiser wheels and run 285/70r17's. that tire is 32.70"'s overall diameter. You are suggesting 4.88's, correct? My truck is a 4.0 with AUTO tranny.

 

Forgot you ha the 4.0 an not the 3.4. You might be better off with 4.56 or 4.30s if you can find them.

 

No problem bud.
You are recommending 4.56 to go with the 285/70r17's or my current 265/75r16?
Thanks

 

I'm running 4.88's on my 4.0 auto with 33" wheels. Lots of power to the rear tires but I run at a higher rpm on the freeway and I lost a couple mpg on the freeway. I would only go with the 4.88's if you don't care about mpg and want all the power you can get out of it if you don't plan on going to a 35" tire later. A 4.30 would keep you pretty close to factory rpm with a 33" tire, so those would go great with your 285's as far as maintaining a factory feel. I just checked ECGS and they don't offer a 4.30 for the 8.4 diff though... They do offer two other locker options besides the ARB. A detroit and a lockright, which I believe are both auto lockers instead of selectable. So you would be locked up most of the time but it will unlock when cornering. Someone else can probably explain it better. haha

http://eastcoastgearsupply.com/i-788575-tacoma-8-4-non-eld-t100-tundra-3rd.html

 

Yeah, I'd hate to spend all that coin when you could have a true locker. I'd skip anything over 4.10s FWIW.

 

Yeah, I wish I could find a cheaper 8.4 complete diff with the TRD LSD. The ARB with everything needed and install is close to 2K from what I have read. Plus. I was looking for something simple. I'll have to really think about this one.

 

You're saying 1600 for a LSD through just differentials right? Does that include shipping.

I'm saying probably 1600 shipped through ECGS with an ARB. Then 160$ for a compressor and you have OBA as well.

You realize they set it up right? You just swap in the 3rd and hook up the compressor kit (EASY).

 

Oh yeah, rear diff is really easy to swap in.

 

OK. That makes sense. Buy the ARB 'd 8.4 diff. I can buy the compressor, air line, & power switches. I guess there's a kit for that, right?

 

Yeah the whole kit is like 160 bucks I believe, you just tap into the stock wiring a couple places and find a place to mount it all, then run the air lines, which I think are compression fittings. Super easy. Then you have on board air too for whatever you might want it for. Roadside flats, air beds, inflatable beach toys, idk...

 

Since no one has mentioned:

Don't forget to bleed your brakes after swapping the diff. It's kinda important.

 

If you just pump the pedal enough they bleed themselves I thought?

 

wow