Auto into 4x4 extreme

The 1UZFE EGR Delete Kit is available for sale here.

Big

Member
Messages
376
Location
New Zealand,Queenstown
Hi guys.. been a while:eek: , Ive built a new truck and goes very well.. but the gearbox is starting to fail.. bearings etc and over the years I have found
Auto, uncut loom
transfer adaptor to transfer case so it bolts to the a340 box
Now I've heard that the tq needs to be strengthened to help with the big tires and possible sc option..?
Im going to put a sc on it later this year and possible the auto but need a bit of info if the auto ratios are ok for the big wheels etc..
I thought it would be ok and wouldnt have any problems..
Can't seem to find searching here exactly what I need so up goes the post..:D
Like the LJ71/78 ratios are different but I still cant seem to even find them.. so I can compare the lexus one..
Any info regarding running a sc and big tires and the auto not blowing to peices would be awesome..

Regards K
 
What size tyres are you planning to run and how heavy is your vehicle I have a hilux weighing 2 tonne with 33 inch tyres the diffs are 4.88 ratio with nitro gears and auto lockers , I have a supercharged 1uz running fact computer the auto is also standard and everything seems to be holding up well. Its been in for 4 years now and shes copt a hiding off road as well as being my everyday driver . I went thru standard diffs at the begining especially the front one being independent front end. I hope this helps
 
Thanks Dante, This is what I need to make an informed decision.. I'll be running 35's and 4.1 gears.. (I know I can change the ratios there) but Im just solely trying to work out if the auto needs better ratios or keep it standard.. As the standard auto is setup for road use on a car that has small tyres.. I have everything out so would rather strip it and get it all right instead of getting it running and then pull everything out.. when things are not right..
Does anyone have the actual auto gear ratios? for the std auto..cheers
 
The standard a340 box can take roughly 400btq (350wtq) on a passenger car with ratios ranging from a stock 3.25 (gs400) to a 4.27 (sc300). I would say an N/A 1uz with basic bolt-ons would be just fine with 35"s. Once you start adding forced induction (extreme gear ratios as well?), this changes things.

My friend has an 02' Tacoma 3.4L with TRD blower at 8psi, water/meth, bolt ons, 33's and doesnt have issues with his a340. He added a beefy trans cooler and maxed out the transmission line pressure. 250,000 original miles and no issues.

Biggest failure on the a340 is a broken sprag due to excessive torque. You can get upgraded billet sprags from boost logic, level 10 or SRT. The second biggest is damaged clutches due to excessive heat (trans cooler necessary). Just a 30 degree drop in trans temp can double a trans life span. Hope this helps some.
 
Toyota/Lexus/Volvo A341E/A30-41LE. 1st Gear 2.531 2nd Gear 1.531 3rd Gear 1.000 O/D Gear 0.705 Reverse Gear 1.880 Final 3.916

Toyota/lexus A340E/A30-40LE.
Ratios 1st:2.804, 2nd:1.531, 3rd:1, 4th:0.705, Reverse: 2.393
With various finals I believe.

Not too sure on the A343F prado box.

Id be using a stock lexus box as they are cheap as and you could have a spare set up to go. Make sure the converter is in good order. Mod the valve body to allow lock up in first and make it switchable by the driver to give engine braking.

Im running an auto in my own truck at the moment as a light 4x4er. LN130 with 4.3 diffs. 2500rpm at a 100km/h with stock 31s. With the auto it isnt in the motors sweet spot. It either wants to sit at lower revs at 80km/h or be at around 3K which is over the speed limit. I quite often find myself happily cruising along at 80km/h with the windows down and the sounds on.
Bigger tyres would bring the RPM down at 100km/h which would work perfect. Off road would also be better as low range just isnt quite right. Look at what all the offroad trials trucks are running. Many of them are autos , often the windom V6 box with 1uz , supercharged 1uz and the LS series motors with big tyres. They are lasting.
 
Thanks guys this is invaluable info.. Just I have heard that you need to weld up the tq and change ratios.. as they are too tall? Was thinking of swapping out a mitsi variant which has better gear ratios but keep the valve body as std.. only thing changed is the gears.. Thats interesting about the sprag.. will research that.
Kelvin, Im going to sc it too so.. if the auto can handle it withg the gear change and everything else std then it'll be awesome.. but if I need to change more stuff then this is why im asking..

Cheers guys.. K
 
James over in Christchurch has a supercharged Cruiser with an auto and last time I heard about that one it was holding up.
Everything here is so subjective. If you take a stuffed ( polite term here) auto then it will shit itself. If you overheat it and keep driving on burnt oil it will shit itself. Yet if you take a auto in good condition and look after it and use a good oil with a effective oil cooler it will give years of service. The ratios are going to depend on you and what you like. When I was younger I liked things to rev so geared them to suit. Now I prefer to use the torque and have much longer ratios. With mine in first gear low box I watch snails pass me , stop to take a breather and still disappear into the distance. 4.3s and smaller tyres than you.
Have you considered doing your ratio alterations with the transfer instead of the box?
Also explain what part of the torque converter was suggested to be welded up?
 
yep big ass trans cooler with a fan on it is a good idea if your doing lots of low speed high load stuff and chuck in a z9 filter and base to add oil capacity

if your going to be doing LOTS of rock crawling i'd look at a multi-plate lock up torque converter so you can keep it locked at all times, otherwise all I would do is pop the pan off and turn the line pressure up like so:

primaryregulator.jpg

this will give you a bit more clamp on the clutches and torque converter lockup
 
James over in Christchurch has a supercharged Cruiser with an auto and last time I heard about that one it was holding up.
Everything here is so subjective. If you take a stuffed ( polite term here) auto then it will shit itself. If you overheat it and keep driving on burnt oil it will shit itself. Yet if you take a auto in good condition and look after it and use a good oil with a effective oil cooler it will give years of service. The ratios are going to depend on you and what you like. When I was younger I liked things to rev so geared them to suit. Now I prefer to use the torque and have much longer ratios. With mine in first gear low box I watch snails pass me , stop to take a breather and still disappear into the distance. 4.3s and smaller tyres than you.
Have you considered doing your ratio alterations with the transfer instead of the box?
Also explain what part of the torque converter was suggested to be welded up?
It was mentioned that the internals not sure exactly but there are fins/veins ? which are spot welded..?? Havent seen inside of one so can't really comment, why im asking
Bert ( he's been speaking to you on the phone)and I and basicly doing the same thing but he has deaper pockets then me..:D But because of the size of wheels etc Im going to run it makes sence to do some changes.. yea thought of reduced gearing transfer side.. may still do this if its a mare to get auto right.. would rather have a std setup as easy to fix/repair etc
I need torque as well and most likely change diff ratios at a later stage.. but if the horse power is good enough I wont have to.
There is also the pto winch setup to consider too by going auto it changes how you ingage etc.. from what ive been told..
If the trans can take a hiding, turn the wheels at full revs on std internals and give reasonable power and not shift up the gears in a blink of an eye, run throw to limiter in each if WOT is acheived then I guess its what Im looking for but there have been discussions about a few things so Im researching so I dont have to pull everything because I didnt research..
you know the rule of thumb.. research research then research before you modd..lol Ive got most of the parts now but if I need to get tq flushed/ cleaned then welded( ? ) to make it take a pounding then I'll do it..If I don't need to then I wont..
From what ive read so far.. the tranny can take a beating if kept cool and is in good condition.. but it's the size of wheels that will really stress things. along with a sc so I just wnat reliablility etc.. otherwise i'll stay manual.. and recond that. bearing are starting to fail.. been like that since Ive owned it..lol
 
A tidy up of the converter can't hurt

Why are you thinking of running stock management for the auto? It works really well for normal road use but I dont think its great for offroad. Id be putting something tunable on to control the box so you have normal auto function and then switch over to lock the box into any selected gear. Id also mod the valve body to allow lockup in first gear and and make that driver switchable as well. That way you can have some engine braking down hills.

We are just organising making the lockup switchable and able to be used in first on the A650 in the V-cross we did.

Maybe I need to ask Bert more questions about what hes doing. I didnt know he was building a more offroad type truck. He was thinking of prado box.


We have a customer that was running a 6v71 blower on his uz in a laurel making 240rwkw and the stock box was fine. He drifts it and does plenty of burnouts. He had a so called expert build him a supra box and it was crap. He has since swapped to a A650e and built his own controler. just wanting the extra ratio. They did get the programming wrong and pop one when they where playing with shift patterns but have since sorted that and a stock A650e is taking the punishment like the early box.
 
Hi Kelvin,

Yip i was going to get a switchable controller setup for cruising and have it ready to roll offroad as well..
Bert's truck will be a winch challenge truck, he is doing his extreme for reliablility and hates things breaking so he's doing the overboard thing but I guess it means it's strong and can handle it.. I think he is getting some mixed info about the whole tranny thing too..
the 6 71 blower from what I know is very tall and I want mine under bonnet so was going to try to find a 112 but most likely go for the 90.. have a intercooler under it to help temps.. but basiclly keep as most as I can std so its easy fix etc.. Im not looking at huge hp but just enough for the lower down torque.. shit 30% increase is great.. more even better less well I guess it's less..lol but hoping for around 20-30% over std.. that should get things moving better..
If you have something in mind for a controller Im interested..:D and sure Bert might be too..
all I want is reliable motoring that can take the pain, if the std auto can then sweet.. if not then I'll make the right changes so it can..

cheers K
 
the 20kw more you get out of an m90 vs the 50kw or so you get from an m112 for the same boost makes it not worth it unless the m90 kit is VERY VERY cheap
So you say for the same amouint of boost say 6-8 psi on the 90 versus 112 I'd get an xtra 30 kw by just having the 112.. Might want to explain that a bit more.. as psi in should be the same kw out i would have thought.. UNless you are tuning more add ecu, decompress heads ( new pistons etc..) then I get where you are at.. but an unopened box 6-8 psi from either I would ex pect the same..?
 
Its hard to know who to believe on how much power the boxes will take in the 4wd application, I had the same issue when i built my hilux, I got that may different stories, that you would though there were a hundred different types of trans combo to run.....
In the end I used a bog standard 3 litre prado box (picked because the diesel had about the same torque as the 1uz), used the standard untouched 1uz torque convertor. I shimmed the accumulators to about 50%, we also didnt hook up the lockup, and I made a big as transcooler out of a civic aircon radiator.
4 years of thrashing, including the last 2 where its been supercharged, and its never missed a beat, that running 35inch tires, usually aired right down, and 4.6 diffs.
Maybe I got lucky with my trans, but they seem to be a tough little unit.
 
So you say for the same amouint of boost say 6-8 psi on the 90 versus 112 I'd get an xtra 30 kw by just having the 112.. Might want to explain that a bit more.. as psi in should be the same kw out i would have thought.. UNless you are tuning more add ecu, decompress heads ( new pistons etc..) then I get where you are at.. but an unopened box 6-8 psi from either I would ex pect the same..?

the M112 will be spinning slower and have less parasitic loss, discharge temps from the M112 will be MUCH lower so you can run more advance etc etc..
 
Does your plan have a tail pinned onto it and can we call it a weasel?
lol.... you'll just have to wait an see..
Also might have to have a chat too.. there seems to be some confusing information out there.. and seeing as you have a little knowledge about what I want to do.. you could help.. :D
 


Top