Matt16

He's a member on the site. Try sending him a PM. He has a great website as well.

tc

They have a double diamond, are kind of gold colored and have a small spot ground in the side and the CL distance scribed in.

ZUK

iTrader: (1)

Hi bktaco....
You have mail.

space-junk

iTrader: (1)

so, ballpark, what are you paying for dual TTs and 4.56s??

bktaco

thanks for the speedy reply ZUK, re TT installation. all: i see ZUKs quote as being confidential until i contract with him and the job is complete, but let me assure you that it seems more than fair, and certainly less money than i have time or skills to complete the job.

now i am only left to consider whether i am going to gear down as well as install the TT. obviously this would be the time to do it, just need to jiggle it around in my brain some more. i am riding 31" tires on my daily driver/expedition vehicle, and i may never feel like going to 33". so i need to decide whether to bump down to 4.56s or just keep rolling my 4.10s. complicating factor: i have a R151F and xfer case from a turbo truck, which i will install someday, but probably not any time soon. so when i do, i will have slightly more gearing on 1st and 2nd... complicates the 4.56 question for me. any thoughts? much appreciated.

tc

4.10 to 4.56 will be NIGHT and DAY. If you do it, you'll think you were a fool for even questioning it.

bktaco

i just did the calcs for gears and TTs for front and back. i think this will be a great set up for me, but it will cost me nearly 5 times as much to do it, versus just a TT in the front. I am thinking of sticking to installing the front TT during this seal replacement job. in the mean time i will dream of taking it to the next stage next time...

tc

Just realize you're gonna pay almost the same again when you regear the front...

bktaco

it will cost a little more in the end to do the gears and rear TT later. here's the break down: in round and conservative numbers $650 for the front TT now, and $1400 for the rear TT and front/rear gears in about two years (or about next time i do the front axle seals). that comes to a total of $2050. i would save about $200 to do all the work now (about $1850). (all these numbers include shipping and ~5% fudge factor).

i am pulling the axles out to do the seals now, and i can afford a TT in the front. I will have to spend the extra $200 down the road, i just cant manage the nearly 2G for the whole job right now. by then i might have re-decided on a toy elocker anyway...

bullcrew

Stuck 33x12.50s on last night with black steel wheels. TTs and 5:29's going in both front and rear this weekend pending UPS gets them here today and the mechanic!
Doing rogers 2" bl and BJ spacers soon as well as fj 80 coils!

Matt16

I did this a couple months ago. I was amazed- the difference was profound. Its a one gear difference on hills and it always feels like there's a perfect gear for the incline now.

Its not just a matter of giving 10% more perceived power (I know this is not true from a physics point of view). You also bring the engine back into its torque band.

bktaco

so you are saying that you get the gearing benefit at the high end (freeway) as well as the low end (take off)? either one more than the other?

also, what is your rpm at 60 mph? i know, i can work up a table, but just looking for a quickie estimate. thanks again.

bktaco

86 yota, ewong, tc:

Do you fellas have part numbers for the front and rear TTs? If you can provide these, please specify IFS or SFA. My truck is 85 4runner with SFA. It seems that I've seen a couple different part numbers for the front:

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

confusion. hoping to sort it out soon, and giter done before the snow starts flyin. thanks a million in advance

saitotiktmdog

I got genuine gears but I have a tt in my front diff and a quick lock in the rear. Seems to be a great setup for me.

tc

bktaco - front and rear thirdmembers are interchangeable on your '85 - should be the same part number unless they have a "loose" one for front application... Even if they did, I would get the tight one - it's still not tight enough IMHO.

As for the effect of the gearing difference - I would say you notice it MORE on the highway because it brings your RPM into the engine's powerband. Each step in gear (say 4.30 to 4.56 or 4.56 to 4.88) will increase the RPM on the highway by about 200. So, you go from being just out of the powerband to just in the band. It's not like you go from lugging it to tached out!

bullcrew

529s and tt f/r all in and amsoil 2000 gear lube!!!!!!

Matt16

Its better for both. It takes off much better, and I can be in 5th gear regardless off a headwind or not now. Its perfectly matched to 31" tires.

The speedo take off is at the T-case output, so whether you have 3.90 or 5.71 gears, 27 or 38" tires, your speedometer is still going to read X rpm at Y speed. At the speed everyone else usually does on the highway (65mph?), the engine is quiet comfortable and still has lots of pickup. Fuel economy went up in the city and is about the same on the highway.

Matt16

Its better for both. It takes off much better, and I can be in 5th gear regardless off a headwind or not now. Its perfectly matched to 31" tires.

The speedo take off is at the T-case output, so whether you have 3.90 or 5.71 gears, 27 or 38" tires, your speedometer is still going to read X rpm at Y speed. At the speed everyone else usually does on the highway (65mph?), the engine is quiet comfortable and still has lots of pickup. Fuel economy went up in the city and is about the same on the highway, but the fuel economy changes weren't as drastic as I thought at the start. I recently came out at 17mpg mixed, lots of big hill (I live on a mountain), short trips, and stop and go.

tc

Ummm .... FAIL

Since the truck travels a different distance for each revolution read at the tcase, the speed indicated on the speedo can be wildly inaccurate.

Matt16

Where did I say the speedo was accurate? (I didn't) I know mine read about 110km/h when I'm doing 90.

Fact:
The speedo cable is spun by a gear on the output of the T case, thus the speedo measures prop shaft speed, and calculates a speed it thinks you're going.

Fact:
The speedo does not measure ground speed.

Fact:
The speedo is going to read X speed, at Y rpm, in Z gear no matter what size your tires are or what diff ratio you have as its all downstream.

Fact:
From the factory, the speedo must read somewhere between 6% and 10% (not certain on those figures) faster than the actual speed. This is required by all manufacturers. It must certainly not under-read.

What's your beef with that? Where's the flaw in my knowledge, if there is one, I'd like to correct it.