Auto Trans Replacement Tips

[natesterrano]

Hey there,

My Auto Box decided to crap itself Friday, I took it down to Auckland Automatics this morning hoping it would be stuck in some sort of limp mode but the guy took it for a drive and then summed up that it was poked.

Been looking around trademe and there's a few auto boxes that are pretty cheap! Anyone have any experience changing them? I feel its gonna be a pretty big job judging by the weight of the dam thing.

Also, if anyone has a good used Trans please hit me a text 021477771

[Jay]

Gidday...

Ummm - you didn't say what kinda vehicle its for?

Not a major job - but like you said, awkward because of the size and weight of them.

Cheers,

Jay

[natesterrano]

Sorry! Not thinking straight this morning. Its a 93' Terrano td27t. Looks like im gonna go pick up a box today with 150,000 kms on it for 450$. Seems like a pretty good deal, hopefully its sound.

[BlakeNZ]

Check the colour of the trans fluid.If it is milky or brown/black, walk away.If it is empty of fluid, so you can't tell the colour, tip it up on its end, normally you can get some to run out of the spline area.(though this is obviously more difficult if transfer case is still attached).
Failing this, undo the trans pan, (not a big job- 2 or 3 mins) and inspect the colour of the remaining oil.

[Jay]

Once you get it, not a big job... You will have to drop the torsion bar adjuster rod thingee's... make sure you measure ride height and mark the bolts before you take them off, makes it easier when you put it back together.

If you have an engine lift, i've found it easier to put the engine lift through the drivers or passengers door and put a strop around the trans from there and lower it that way. When re-installing, make sure you mate the torque converter to the trans and then lift into place and bolt up rather than bolting to TC to the flex plate first, and trying to slide the trans over it.

Cheers,

Jay

[natesterrano]

Thanks for your input.

Picked up the Trans today, checked the colour of the oil and is as normal.

We have no hoist, So will be doing it on Jack stands. Luckily I just did the Clutch in my Bro in laws 4x4 Rodeo so have a fair idea of how to manhandle the gearbox up. This thing looks even heavier tho!

Also, the Trans didn't come with a torque converter. Do torque converters fail very often? Just gonna reuse mine I think.

[BlakeNZ]

Torque convertors don't often fail. Most people choose to use their original one, on the basis they know it works, compared to a 2nd hand one with unknown history. The exception to this would be, in your case, if you knew that when your trans "failed" it sent lots of metal bits all through the oil, and will now be all through your torque convertor. If you installed such a convertor, it would soon damage your replacement trans. However, most autos do not fail in that manner, but tend to get damaged by slipping and/or overheating.
Make sure that when you slip the convertor onto the spline, that it goes on far enough(there is two or three different splines) Sometimes/often you need to rotate the convertor a bit and then it slips onto the next spline. Putting a convertor onto a toyota A340 trans involves three "stages". Two splines and then the oil pump drive i believe. IF the oil pump one isn't located properly, when you bolt the trans to the motor the snout of the convertor can crush the oil pump. Not good.
If you are unsure, measure how far from flush the front of convertor sits from a ruler placed across the face of the bell housing. (say 10mm?)Then check that you replicate that before you lift the replacement trans in.

[natesterrano]

Yeah true but how would you know if your torque converter was poked?

The issues i'm having with the current transmission don't happen at all when its in reverse gear, would that prove the torque converter is sweet?

Also, once I get it out, ill flush it out and see if any metal particles come out, surely that would be a dead giveaway?

Looks like there's only one spline coming out of the Transmission in this case.

[BlakeNZ]

it's not likely the metal parts have broken off in the trans. there is a trans filter as well. Check your oil, or the filter. its just like a mesh screen. you can see it as soon as you drop the pan.

[The Stranger]

Also, the Trans didn't come with a torque converter. Do torque converters fail very often? Just gonna reuse mine I think.

The TC can and does fail. Mine failed - stripped the spline.
I know of another one this happened to too.
The lining of the lock up system wears out also - this is what commonly blocks the trans coolers and leads to further damage.
I replaced mine with a rebuilt unit from A Automotive. Supposedly uses kevlar lining and a hardened spline. Don't recall the cost right now sorry.

[natesterrano]

So we got the transmission out this avo. It wasnt actually too bad, all the bolts came out easily and still shiny cadmium, the previous owner must have never been 4wding or to the beach, not a spec of rust anywhere! Putting it back might be the problem tho.

I've got a few questions if anyone can help before the install?

- Does anyone know the size of the crank pulley nut on the front of the engine?

-The Trans that I'm installing has been sitting around, full of oil for about a year. Will simply draining the oil, and changing the filter be enough or do you think its needs to be taken to an Auto shop and have the fluid flushed?

- What oil goes in the transfer case? I'm guessing its not Dextron 3 which goes in the Trans itself.

- Anyone have an idea of what size the input shaft seal on the transmission is, or the part number?

[The Stranger]

- What oil goes in the transfer case? I'm guessing its not Dextron 3 which goes in the Trans itself.

Will stick with what I know here and leave the rest for those that do know.
Dexron 3 is fine for the transfer case.
There are a couple of options specified, but if you use one of the thicker grades this can cause the front shaft to turn and thus the auto hubs to try and engage.
Mine had ATF in it and I replaced it with ATF when I swapped my trans out. It has been fine so far.

[bang-thud-thump]

Dont reuse the cooler if in any doubt re metal in the oil!!!!!

Fit a new oil to air unit, they are better anyway if it is an in rad cooler.

Fittint the old TC and finding it poked willmake you swear lots, get it checked I suggest.

Just based on prev experience and seeing some unhappy owners from skipping stages.

[slide]

- Does anyone know the size of the crank pulley nut on the front of the engine?

41mm or 1-5/8"

[natesterrano]

So we finished off the install last night and suprise suprise, this gearbox has the EXACT same issues as the last.

The Problem is that the transmission when in 'D' will only be in second gear, when accelerating away, it has some quite violent lurches. Once you get going, say over 40kmhs the problems aren't quite as visible. When you let of the accelerator and start coasting you can feel small shuddering and the revs slightly spike at each shudder. You can manually shift down into 1st gear, but by itself when in 'D' it will be in second gear and never shift above or below.


I'm at a loss of what to do now really, here's what I think could be possible:

a- The gearbox I bought was stuffed, and either the guy who I bought it off lied to my face or it failed after install, in the EXACT same way as the last??

b- There's some electrical problem with it and I was given poor advice to pull the gearbox.

Has anyone got any other Ideas regarding what it could be? Where is the TCU in a D21 and how much control does it has over the transmission?

Thanks for all your help

[meatc]

Sounds like limp mode. There an Trans comp but cant remember where it is. Could the comp, or could be as simple as the revolution sensor or even the shift switch on the side of the box being out of adjustment.

[natesterrano]

Yeah this could be it, has anyone got any information regarding limp mode and how to find what sensor could be causing the problem?

[Bonus]

have a look at this

http://www.offroadexpress.co.nz/Forums/ ... 25&t=33733

[natesterrano]

That looks all good but there is no "power shift indicator lamp" on my dash so their way of diagnosing doesn't work. Is there still a way to get a fault code out of it? The truck in question is a 1992 terrano. I dont wanna accept that the trans I have put in has the exact same problem..

[kiwipete]

That looks all good but there is no "power shift indicator lamp" on my dash so their way of diagnosing doesn't work. Is there still a way to get a fault code out of it? The truck in question is a 1992 terrano. I dont wanna accept that the trans I have put in has the exact same problem..

The indicator lamp is in the switch itself, not the dash, from memory mine has a green light when in "hold" and amber/red light when in "power" on the switch itself. Try that with the sequence mentioned in that post?

[nizute]

if it is the trans i got a good one(that you can road test if you get hold of me before sunday) , where abouts are you ?

[nizute]

And i think the trans computer is above you feet under the dash,i will have a look tonight and you could grab mine and try it.

[fullthrottle]

A couple of things. Do you know what model trans you have?
L4N71B or RE4R01A (you can tell from the shape of your oil pan between the two)

I have a good service manual for both and they discuss in detail how the electrics work, sensing and controlling the trans. Do you have a copy of this? It's been floating around for some time.

Did you use you old TC in the end? So everything in your truck is the same except for the trans unit itself, right?
If so, I would be amazed to see that two completely different trans units have exactly the same problem. There are a number of other checks that can be done before you buy any replacement parts.

[natesterrano]

A couple of things. Do you know what model trans you have?
L4N71B or RE4R01A (you can tell from the shape of your oil pan between the two)

I have a good service manual for both and they discuss in detail how the electrics work, sensing and controlling the trans. Do you have a copy of this? It's been floating around for some time.

Did you use you old TC in the end? So everything in your truck is the same except for the trans unit itself, right?
If so, I would be amazed to see that two completely different trans units have exactly the same problem. There are a number of other checks that can be done before you buy any replacement parts.

Im unsure at the moment as the removed transmission is at a friends house but that would be very helpful if you could send them my way. My email address is : nathanrusbatch@gmail.com

No I ended up wondering if my Torque converter could be the problem so the guy I bought the Tranmsission off found the Torque converter and sent it up to me. So it has a new Transmssion and Torque converter, yet same problem...

That looks all good but there is no "power shift indicator lamp" on my dash so their way of diagnosing doesn't work. Is there still a way to get a fault code out of it? The truck in question is a 1992 terrano. I dont wanna accept that the trans I have put in has the exact same problem..

The indicator lamp is in the switch itself, not the dash, from memory mine has a green light when in "hold" and amber/red light when in "power" on the switch itself. Try that with the sequence mentioned in that post?

As for the power shift indicator light, ok now I understand. When you move the switch to the hold position the green light comes on, but when you move it to the power position no red or amber light comes on.

Now I must troubleshoot why the power shift light is not coming on for 2 seconds before startup before I can get a fault code off it. I need to know where the Transmission control unit is for this however, as you need to test resistances accross some of the control unit pins. Anyone have an Idea where it is?

And i think the trans computer is above you feet under the dash,i will have a look tonight and you could grab mine and try it.

Took off that panel this avo and pulled that unit. I think that is the torque converter lock up unit. I pull it out and opened it up and the circuit seems to be in good condition. It may still be worth swapping with you tho? Im in Onehunga.

[natesterrano]

A couple of things. Do you know what model trans you have?
L4N71B or RE4R01A (you can tell from the shape of your oil pan between the two)

I have a good service manual for both and they discuss in detail how the electrics work, sensing and controlling the trans. Do you have a copy of this? It's been floating around for some time.

Did you use you old TC in the end? So everything in your truck is the same except for the trans unit itself, right?
If so, I would be amazed to see that two completely different trans units have exactly the same problem. There are a number of other checks that can be done before you buy any replacement parts.

Actually, from looking in google images of the two its the RE4R01A in my Terrano

[natesterrano]

ok, found the Transmission control unit, its right behind the the driver side rear speaker. Very strange location.

Anyway, I definetly think it could be the culprit, the box had visible corrosion in one corner, and one a few drops of water came out of that corner whilst I was undoing the case. Got a new one coming up, hopefully monday! Take a look and see what you think...

[Dirtydog]

Its not a bad place to keep it in my opinion, keeps it out of the water (aslong as you have no leaks....)

[nizute]

Ha ha should have looked here just traced the wiring thru to the computer, oh well.
If you get stuck for any parts let me know i will start wrecking my terrano on Sunday.

[fullthrottle]

The document I have is 173MB, will try and upload it somewhere over night.

However this document has pretty much everything.

http://www.caixautomatica.xpg.com.br/ma ... E4R01A.pdf

Something interesting I just learned. This trans comes out in the 240SX, wonder if its identical.

[natesterrano]

Took it for a drive without the computer (manually changing between 1 and 2 ) and it runs mint!

Hopefully ill put the new comp in and all will be well. I guess at the very least I got to change my rear main seal that was leaking a tiny bit and got a lower km gearbox. What a pain tho!

Thanks everyone for the help!

And yep I found that website also, very helpful.