I have 91' Toyota xcab with the 3.0 v6 and automatic transmission. I am in the process of putting in the 529 gearing, ARB front, Detroit rear. I already did the 63" Chevy's in the rear and the s.a.s. My question is; will the automatic (stock) transmission be strong enough and do they make a duel transfer case kit for this or do I even need one? I am new to the Toyota Wheeling. I have been a hardcore Jeeper rock crawler for many years and am changing to Toyota. I have an automatic in my jeep and love it (effortless). I would like to stay with the auto in the Toyota but not sure about reliability.
Does anybody have any input??

 

A lot of the guys here like their autos. Some of the 3rd gen guys started experimenting with upgrades after they installed superchargers. I think Level 10 was one of the more popular companies. I think the stock auto can work as long as you upgrade its cooling. Sounds like you are going to have an awesome truck. Oh yeah - Look into Marlin Crawler to see if there is a way to dual case your truck.

 

Inchworm makes adapters for duals

I wheel an auto/3.0, I like it in its stock form. I wheel sloppy, tight, midwest trails and like having some wheel speed. Oh and it is MORE than strong enough.

 

You shouldn't have a problem.

I've had more 4wd trucks/SUVs with manual transmissions than with automatics. Overall, I've had fewer problems with the automatics. My experiences may be a fluke, but they are what they are.

One problem while going slow or not moving off road is cooling. A manual will have little or no air flow to cool it while moving slow or sitting still (such as when you are stuck or going slow off road). With little or no air flow, and little or no gear oil/transmission fluid flow (some manuals do use automatic transmisson fluid), the transmission can experience heat soak.

But an automatic will still have the transmission cooler and radiator cooling fan to cool it, especially if you have an extra transmission cooler like my Tacoma with the towing package has.

With the manual, you have the clutch that will eventually need replaced, and the potential for more shock load than with the automatic. With the automatic, you won't have the clutch, and the torque converter absorbs shock load.

With the automatic, towing and big tires (especially with the factory gear ratios) will create more heat because of torque converter slippage. But you can also add or upgrade to a larger transmission cooler to cool the heat. And installing lower axle gears will make up for the bigger tires.

Then there's the obvious advantage of an automatic requiring less effort to operate. When you are off road, there are situations where you are better off with fewer distractions. More effort means more distractions.

The manual does have some advantages (such as better compression braking). But I prefer an automatic.

 

Neat. I also wheel in the exact same conditions with my auto. If I could get a little more power out of my tired 22RE, it would be perfect.

I also do not get any "incline fluid drain" effect at all. Uh, tho I do have my tranny overfilled, hope that's OK.

 

heres some information from MC here - http://www.marlincrawler.com/htm/tra...up_dual.htm#v6

 

I don't know that Marlin makes anything for the Auto tranny.


I don't know what tranny is behind a 3.0. I have the inchworm adapter to mate the A340H auto that is behind my 22RE to a gear driven case. Nice piece although I have yet to test it out because the buggy is not done.

 

I didn't want to infer that Marlin does. I have a 5 speed so I don't look at the products for autos but with all the adapters out there I thought looking at a few vendors was a good idea. The auto is a dog - I drove 5 speeds and autos before I picked my truck.

 

Inchworm is the only adapter for the pretaco automatic. The autos are siamesed to their transfer cases, so it's quite a deal to adapt them. The adapter is $550, then you need a gear drive case (or two).

You MUST install an additional tranny cooler. After that, it will hold up just fine.

The big problem with the automatic is the monster overdrive. If you really want to drive it on the street, you're looking at 33's, maybe 34's max tire size. Even with 5.71's, you will just barely be able to use the overdrive. 35's and 5.71's you just bought yourself a 3 speed no O/D tranny because it will only be in overdrive downhill with a tailwind, and even then probably not locked up. Pretty good 1st gear/crawl ratio though.

I have both a SAS/V6/auto/35/5.71 and a IFS/V6/manual/33/4.88. For all-around use, I'll take the manual transmission truck every time.

 

Thanks for all the responces! So far it seems that the automatic is ok except for maybe lack of power. I will be putting in 529's this weewend and that should help. Are there any upgrades that can be done to get any noticable power? I live in CA. so what ever is done cannot interfere with smog. Thanks again for all responces.

 

No, with the V6 you're pretty much stuck with what ya got motor-wise. Search around and you'll see that all the mods for this motor have pretty mixed reviews. Headers and cams are about the only thing that may be worthwhile, and even then, the improvement per $ spent is not real good...

Gears are be your best friend offroad, and the 1st gear ratio is sufficiently low (especially with the "magic" 2x from the torque converter) for decent crawling. If you're over 35's though, I would look at putting in either a 4.7 case (if you ONLY do rocks) or dual cases (for everything else). Dual cases will help with your front driveshaft angle (a common trouble spot) too.

 

the best advice is if you plan to use an auto with big tires and off road get an aftermarket tranny cooler. I will be running a large cooler with its own fan...

 

What is this "magic" 2x from the TC that you speak of?

 

At low speeds, the torque converter multiplies the torque from the engine by 2X, almost acting like a doubler. I've never seen a good explanation though of why that is (and therefore the "magic" statement) It's why if you put dual cases behind an auto tranny you can't stop the truck at idle with the brakes...

http://auto.howstuffworks.com/torque-converter.htm

 

my Runner is an auto with 5.29s and 35s, and i can stay in overdrive no problem, even going up slight grades...

 

When a torque converter is unlocked at crawling speed the crankshaft is moving faster then the input shaft on the transmission. The torque converter is not a direct link from crank to tranny like a clutch. Most people factor in an extra 2 when calculating crawl ratios on truck with an automatic transmission saying that the crank is turning twice as fast as the input to the tranny. This is a rough number and of course to get the exact one you would have to factor in many things about your vehicle. 2 is just the accepted norm in the rock crawling world...

 

thank you for the responses guys, that makes a lot of sense!

 

Just remember all that constant slip in you torque converter at low speeds will fry your ATF and in turn you transmission. A good cooler is a must and then you will have no problems..