IN YOUR PROFESSIONAL OPINION..

STONEDGOAT

GEEEZUS WHERE DID THAT NUT GO!!!?
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1994 ISUZU RODEO 4WD 3.2L MFI SOHC 6CYL.
Automatic Turbo Hydra-Matic 4L30-E transmission (I think...)
170k miles

I am pretty certain that this transmission hasn't been serviced in quite some time as I know the previous owner personally if at all.

I acquired the vehicle more or less by default as he left it parked on my land for several months. He was, shall we say, a guest of the county for that period. At any rate he didn't want it, signed the title over to me, etc. but I digress.

First let me say the vehicle is a "beater" and is good for what it does. Getting you from point "A" to point "B" around town. I am giving it to my son for his "college car" and he is dead set on changing all the fluids, new wires, plugs, filters, performing much needed maintenance. :p

The transmission shifts smooth enough through all its gears for the amount of mileage and the years of abuse it has endured. However, when you "put your foot in it" as in to pass someone or sometimes when you accelerate to say climb a hill or incline on the highway it will downshift as expected but thats all it does. There is no appreciable increase in power or speed. The motor torques up but you get jack squat for the effort. There is no huge jump in rpms according to the tachometer as I have seen in a manual tranny when the pressure plate is going out, so I don't think it is slipping. But I no jack about transmissions.

Replaced the vacuum hoses which were in sore need of same with little or no improvement.

My son wants to change the fluid and filter and in addition he wants to throw in some sort of additive to recondition the seals, gaskets and what not thinking this might help things all around. He was told by a mechanic that this wasn't a great idea as it would "throw the transmission into shock" and possibly do more harm than good. ???

IN YOU PROFESSIONAL OPINION: what could be the cause of the root problem?

Is it a bad idea to replace fluid/filter in a transmission of this mileage and questionable maintenance record?

Do these transmission additives actually help and if so which would you recommend?


As always I want to thank you hard working professionals for your time and patience. I know all of you have "real jobs" and this is above and beyond for you. You can't imagine how much you and this site helps those of us who are mechanically challenged.

Respectfully,

STONEDGOAT 8)
 

Transman

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Well written and well thought out! That being said, DO NOT CHANGE THE FLUID IN THIS UNIT (I didn't want to shout, just make the point). Think of this, let's wait to change the motor oil until 100k of abusive miles and see how the engine responds afterward. Yes, this is a huge shock to the system. Trans fluid never changes or dies, it is always transmission fluid. The stuff that does disappear, gets used up, dissolves, etc is the additives. Anti foaming agents, friction modifiers, detergents, anti-corrosives and a bunch of other goodies. Now add all this in one shot to a tired gummed up transmission and they start doing their job, cleaning. They will clean all the gummy gooey stuff that is just sitting there doing nothing. Now this mass of junk, pieces of bushing material, steel parts that have worn make a headlong rush for the Valve Body trying to get to the pan. The valves are made to throw junk out rather than stick but the sheer mass of junk would be like removing it and tossing it into a beach dune, roll it around for awhile and install it back into the trans then expect it to work. Not to mention that the glue holding the clutches together is tired and weak also, let's get the fresh detergents to work on them for a bit and see how long the glue holds on before the clutches and band material let go.
OK, there is worst case scenario. What good can come from a service.... um..... hmmm.... There in lies the rub. A service is just that, we change the fluid & filter to keep it fresh so it doesn't shock the system. It does not perform any useful function, it doesn't FIX anything and in this trans, since there are no band adjustments does no repair functions at all. To use the engine simile again, it would be like expecting an oil change to repair spark plugs, ignition wires, cap & rotor, AND repair a rod knock at the same time.
Sorry about the book here, and I haven't even gotten on my soapbox about additives! If you are dumping the vehicle on some unsuspecting sucker and have no conscience then by all means try the additives. They tend to have a "slingshot" effect, they work for a while but utterly destroy whats left of the trans as it crashes and burns up. There is one additive that I do use and believe in, Lubegard. It has been tested by many manufacturers and passed their tests. I don't believe the additive is a fix all but it does some interesting things inside the trans. I will recommend it under certain conditions for specific problems, yours is not one of them though.

For your specific problem, I would examine the modulator for fluid on the vacuum side and replace it if even a whisper of fluid is there. If you wish to try the fluid change, sigh. Drain the fluid into a clean container, change the filter (although this one should be a very cleanable screen) and if nothing is in the pan, change it. I would recommend you simply install the same fluid back into the tranny though. If you have any further questions, feel free to post and I will try to clarify further. Transman
 

STONEDGOAT

GEEEZUS WHERE DID THAT NUT GO!!!?
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Transman,

Thanks for the prompt turn around to my post. My son was about to worry the shit out of me about changing the fluid/filter to the point I had to threaten "repossession" of the damned thing. |!!|

Your explanation made perfect since and its easy to see why the fluid change would do more harm than good. Nothing like throwing a handful of metal infested dirt and sludge into an intricate piece of machinery to get it working right. |8

I will go out and inspect the modulator for fluid as prescribed. Never mind its 12:42 a.m. local time. I would send the boy out there drop light in hand but he doesn't know a distributor from a coil pack God bless him. Never got the same breaks from my old man, but he was a professional mechanic and there would be no hands-off vehicle repair as far as he was concerned. You drove it, you maintained it, you worked on it. He was always there for consultation and instruction when you came up against something that was above your pay grade. Unfortunately, he is no longer available.

This is what makes this sight so invaluable to me. Can't thank you and BAT enough. <img src="http://static.flickr.com/63/255249227_1dd4a59b27_o.gif">

Off to the trenches and will report back my findings.

Respectfully,
<img src="http://tbn0.google.com/images?q=tbn:OfYoeYXjA0WWKM:http://c1.ac-images.myspacecdn.com/images02/48/s_b88f63269a2f4c0784a38652c96b4284.jpg">

STONEDGOAT
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partsgal

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"bow" "bow" to the transman..you are awsome..you are the man!..I have told people over and over again NOT to flush out an old trans and they never listen...then it is junk..
 

Transman

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The history on this problem is fairly interesting. It comes from one trans in particular, aside from the really old trannys that had as much band material as the brake shoes do today. It was the 400 trans. These units had so much band & clutch material that even when it went bad, it would still work. If fact, it would drop enough material to clog the filter. If you changed the filter and fluid, the trans would work fine for a while longer. At least until the trans crapped ALL the clutch and band material, then it would work a bit longer. I am glad the explanation was clear enough, I tend to get on a soapbox on this issue AND trans flushing. It's funny when the customer thinks you are trying to rip them off when you are explaining why it is unwise to change their fluid. I will actually spend more time explaining why I don't want to service a bad trans then it would take to actually service the trans and STILL have some people that insist on the service. It happened once at my Cottman center that the car refused to back out of the shop after the service, then the customer thought we did something to break his tranny because "it was fine before the service". I had, of course, explained why I shouldn't service his trans and documented on the repair order that he signed before the service. SOME people NEVER learn, sigh. Feel free to post any other soapbox questions and I will be happy to stand on it for you, Transman
 

stu

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It happened once at my Cottman center :eek:

Cottman? Yikes.

I had an AAMCO centre.

Now I see they have merged.
 

Cheef

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Transman,

Thanks for this article. My best friends girlfriend has a Jeep GC that she wanted me to service the trans. Fluid is clear, not burnt, but it is very old. I figure 120K on it with 180K on the odo. Her idiot brother, "the master mechanic" put 4 point Bosch POS platinums in it and she said it did not run right. Amazing what a set of OE plugs (4.0 IL-6 engine) does. Anyways, needs a new CV axle and upper ball joint drivers side and I may try and install a set of rod ends too. I told her just drive the rig until it dies (no problems with it right now (42RE)) and then I would rebuild for a song and a six pack....well a song anyways.

Great write up, thanks!

Cheef
 

STONEDGOAT

GEEEZUS WHERE DID THAT NUT GO!!!?
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<SIGH> I know when I am beat. :p I can also be big enough to admit to when I ran my big mouth about knowing more than I think I know. Transman, I haven't the slightest idea what a tranny modulator looks like. I have searched high and low on the internet and even found a very detailed GM manual on my particular tranny. But I be damned if I can find anything referring to a modulator. ??? Help? :'(


respectfully,

STONEDGOAT
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STONEDGOAT

GEEEZUS WHERE DID THAT NUT GO!!!?
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Another quick question. In my search for a diagram, photo, or anything referring to a modulator on my transmission I scanned through more web articles, sites, and the like than I care to remember. Many of them said that this transmission did not have a dipstick to check fluid level. In fact most mentioned having to remove a plug of sorts and look for "transmission fluid dribbling out" to know that it was at the proper level. Well, this tranny has a dipstick. :eek: Do you think this is an aftermarket add on? If so should I check the fluid level via the aforementioned method? ???

Your thoughts?


Respectfully,



STONEDGOAT
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Transman

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The 4L30E does not use a vacuum modulator, sorry. I just see 4L30E and think THM 180. The "E" part removes the modulator from the unit and makes it computer controlled. I would recommend checking the Kickdown switch adjustment as well as the Range mode switch (neutral switch). Also check to make sure the "Winter Mode" switch is NOT depressed as this will noticeably decrease performance. This is for driving on slippery roads.
Check the fluid using the dipstick, they disappeared in newer vehicles. If yours has one then it came with the vehicle. Post results, Transman
 

STONEDGOAT

GEEEZUS WHERE DID THAT NUT GO!!!?
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GEEEEZUS...

Crawled underneath the thing after making sure the Winter Mode switch was not engaged. It was not pretty to say the least.

Honestly I have looked underneath the thing briefly at best and never really LOOKED closely. What I saw follows:

The range mode/"neutral switch" and most of the tranny pan and ass end of the tranny is covered in filth, grime, and the tranny fluid that attracts all so well. The bolt securing the switch to the tranny housing was backed out about 1/4 - 1/2 way out.

Wiring harness going to the tranny, which splits to various components I assume are required for a proper functioning transmission, is also soaked in fluid. Some points that run near the exhaust manifold have blatant heat damage in addition to the aforementioned. I do not see any obvious "melt through" to bare wire.

All pan bolts are "loose" and on the smaller of the two pans one bolt is completely missing.

In short it looks like an abortion under there. :p

As an added bonus while looking for the Haynes Manual for the thing I ran across to bottles of EMPTY transmission treatment crap. My son being the most likely suspect. :mad:

AT ANYRATE, He insisted on trying to limp it the 260 miles to college. We got about 20 miles down the interstate before I black flagged him. This after he nearly caused an accident as well as providing me a free near death experience. The thing aka RODEO would not go above 50mph, barely climbed hills, and constantly was "kicking down" and back multiple episodes in succession. :'(

From a dead stop In Drive it would slowly begin to roll forward gradually gain momentum and eventually go to second, then third but with the same slow sluggish acceleration. Which brings us full circle back to it kicking down and back.

I am at a loss.... ???

Your impression? Your recommendation? I got a sinking feeling it's going to cost BIG $$

Respectfully,


STONEDGOAT
 

Transman

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OMG! A scanner would help here to verify that it is not in winter mode, switch could be bad or computer could "think" you want that mode. The symptoms suggest poor running engine, fuel pump issue, clogged exhaust type problem. This would be the most common. I shudder to think of what "Slingshot" effect the trans additive will cause down the road. If you have poor acceleration & poor rise in RPM then suspect the engine. If you have poor acceleration with rise in RPM then the trans is slipping. Just like the old days when your clutch was going on a standard trans. Post back, Transman
 
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