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4L30e Transmission Shifting Problem - with Solution

222K views 94 replies 53 participants last post by  rbral 
#1 ·
Hello folks,

New to the board and am looking for some tech help. I researched this issue on the boards already, but there are conflicting replies.

I have a '99 Isuzu Trooper auto. Coincidentally after having my transmission fluid exchanged at a local establishment, my transmission started shifting very harshly on the 2>3 shift, both up and down. It slams into gear so hard that the drivetrain resonates like a ringing bell. It only seems to do this after the car has sat for a day or so and is used in the morning.

Oddly, this problem will correct itself immediately if, upon realizing the problem, I pull over, shift the tranny into Park, and turn the ignition off. I wait 5-10 seconds, restart the vehicle, and everything shifts fine. I have not yet had trouble correcting the problem using this method.

In reading the board, it seems that some possibilities are the 2>3 shift solenoid and the TCM. I would appreciate some guesses on what the problem is and suggested repairs. Can the solenoid be replaced with the transmission still bolted in, or must it be removed? Can the solenoid(s) be tested in some manner without removal?

I would appreciate any theories. I have a pretty good base of mechanical knowledge, and would be performing any repairs myself short of a total trans rebuild. Thanks for your time.

Regards,
Tom
 
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#52 ·
Autozone had one in stock so I bought it.....$114 with Tax...

I am installing it here in about 30 minutes...I pulled the Trooper in to work on it and the exhaust is hot......

I am looking for this "Cable" but I didn't see any "Cable" that would be part of this R&R.

It looks like a straight swap....and no moving of any linkage positioning needed.....mark where the old one comes off and then adjust the new one so it is the same and just slide it on....bolt it up and plug it in.

I could be wrong....I'll find out in Half an hour.....if this forum had a way to upload pictures "easily" I would take the time to shoot photos.....but to load the photos to Facebook only to hotlink over here is too time consuming....and my friends on Facebook would be wondering why I loaded such an odd album......lol
 
#53 ·
There's always photobucket! :)
 
#55 ·
Welp,

The parts change was a 30 minute deal really......but it didn't fix the issue.

Got the test light out and the Turn and Back-up lights were a blown fuse....replaced that and the fuse blew again in 30 minutes.

My trans shop tried to pull codes and there weren't any....

BUT

Autozone charge test claimed that the output of the Alternator was/is BAD!!

And then on the way home the ABS light comes on...

Electrical gremlins creeping up on me.....

I'm going to attack the Alternator next....I'll post results
 
#56 ·
The Alternator is going in today.

If anyone cares, I found a place in the Valley that is rebuilding the Alternators for $119 and they'll give you a $30 core charge credit if you can send yours in or bring it in.

Best price at the parts houses are $166......and it may very well come from the same place.

I'd like to solve the mystery so that the next poor soul that searches out this thread gets a better idea of what to attack.
 
#57 ·
Got the Alternator out and I'm taking a break and typing with grimy fingers....

I'd like to talk to whoever it was that placed this Alternator.....

I'd like to say that the placement is not funny nor is it cute....they aren't as funny as they thought they were when they designed this one.

You have to get the alt loose.....to disconnect the leads that come from the battery...you can't reach/see them until the thing is dangling from just the connectors....brilliant.

The trans cooler lines are in the way...so you have to loosen them and let them drip until they are empty....another brilliant move.....
 
#58 ·
OK, New Alternator charging 14.4 Volts.....

....I kept blowing the same fuse and hard shifts from 2/3 or 3/2 (downshifts at stop lights etc)

I went after the shift indicator as some said that it fills with gunk and causes the Comp to be confused.

That was ~$100 wasted as it didn't change anything.

Going off of what others posted I had Kragen check the charging system and sure enough the output was not given....just "Bad" was displayed for output.

All the auto parts stores wanted $166 for a rebuilt or ~$240 for a new alternator

I searched around and found a rebuild shop in the Valley that is selling rebuilt Alternators for Troopers for $119 and you can get a $30 core charge if bring back the old unit. I'll be going back up there soon to get my $30bux

So Yeah, after discovering what a pain a bottom mounted alternator is to swap out....I have the new unit in.

The Truck shifts like it should (hardly can tell) and the fuse no longer blows out......No "Check Trans" or "ABS" lights popping on and off....

I'd say that the electronics are fickle and malfunctioning alternator MAY be the fix for these symptoms
 
#59 ·
It definitely sounds like if you didn't fix it, which it sound like you did, you're for sure on the right track!
 
#60 ·
Media, I try to post the results whenever I can.

So many threads just "end" with no resolution....it is frustrating.

Two things have occurred, 1. the problem was fixed and the poster forgets about us as his/her problem is gone.....and 2. the Poster dumped the car and forgot about the issue and us.

So yeah, a real answer to what causes these symptoms would be nice. I searched about 50-100 threads the other night and they all just "stop" with no definitive solution.
 
#61 ·
I just LOVE it when that happens... NOT! lol

I try to do the same anyhow :)

Tony
 
#62 ·
Back to square one....After about 20 minutes of driving, the Fuse blew again and the hard shifting came right back....BUT

I my search for the source, someone mentioned the trailer hitch pigtail.....

Yes I have/had an old one that I ripped off my '98 trooper and put on this one just last summer when I needed a car dolly for my Corvette.

It's raining here tonight so I pulled into a self Car wash. I replaced the 15 amp fuse (Turn signal and Back up lights) then I went into the jack storage bin where the pigtail connection is located and ripped that sucker out. (well I unplugged it and fed the pitgtail out)

I drove the car for another 45 minutes and could not get the fuse to blow again....

...so this whole adventure may be due to the pigtail grounding on something and causing that fuse to blow.

I wonder if you pull the fuse, and check the charging system, will it still show good?

I'm going to drive a little while before claiming that I found the issue.
 
#64 ·
jhammons01 said:
Back to square one....After about 20 minutes of driving, the Fuse blew again and the hard shifting came right back....BUT

I my search for the source, someone mentioned the trailer hitch pigtail.....

Yes I have/had an old one that I ripped off my '98 trooper and put on this one just last summer when I needed a car dolly for my Corvette.

It's raining here tonight so I pulled into a self Car wash. I replaced the 15 amp fuse (Turn signal and Back up lights) then I went into the jack storage bin where the pigtail connection is located and ripped that sucker out. (well I unplugged it and fed the pitgtail out)

I drove the car for another 45 minutes and could not get the fuse to blow again....

...so this whole adventure may be due to the pigtail grounding on something and causing that fuse to blow.

I wonder if you pull the fuse, and check the charging system, will it still show good?

I'm going to drive a little while before claiming that I found the issue.
let us know if that fixed the problem
 
#65 ·
Hey everyone, it's your favorite thread!

So I was just under my truck, looking at my Range Mode Sensor, because I need to clean mine. It seems like the issue with mine, is that there is a leak, that is leaking directly onto/into it. Is there a seal that I could replace between the transmission body, and the 14mm bolt that secures the RMS to the transmission? That is where the leak appears to be coming from.

Actually, I'm going to try and take a picture for everyone, since none of the pictures/pdf links in this thread work anymore. Be right back.
 
#66 ·
When you remove the Range Mode Sensor, is it correct that you need to put the transmission into neutral AND disconnect the battery? What is the significance of both of those steps?

Here is the Range Mode Sensor, in case anyone is curious. That metal shield just pops off with no tools by the way. EDIT: Sorry I didn't take a picture with the cover off, I was trying to keep my hands clean. When I get around to cleaning this, I'll be sure to take pictures.



Here is where the electrical plug, plugs in above the unit.


Here is a close up of all the crud.


You should be able to see how the shield is wet with fluid that is coming from behind that 14mm bolt. I could not get a good picture of where that bolt passes into the transmission behind the RMS, but that is where everything is coming from.



So is there a seal behind there that I can replace? Thanks for the great responses on this site.
 
#68 ·
I have a 2000 Isuzu Rodeo w/ the 4L30e tranny. The past year or so, it has had a very intermittent shifting issue - shifting hard every once in a while. It has about 60k miles on it, and has not had the transmission fluid replaced. About a month ago, the transmission made a loud knock and shifted hard - a day after, it would start out in 3rd gear and not want to downshift. I could manually select 1st and 2nd with the shift lever, and although it would shift slowly and rather hard, it worked fine. I took it down to a local transmission shop and left it there to have them diagnose the problem. I had them do a transmission fluid and filter change - the fluid was dirty, but nothing out of the ordinary. The Rodeo ran fine for a bit, then continued to have the same trouble. Transmission shop came to the conclusion that the tranny was failing and it would cost $2800 to repair.
After researching online and reading some posts on this forum and others, I began thinking it may just be an electrical issue. A day later, I was in line at a Costco gas station and the car stalled - the battery was from Costco, so I had it replaced under warranty (it was only a year old) and she ran fine home. Realizing there was a problem with the battery not being charged, I took the Rodeo down to Pep Boys and had them run a check on the alternator - it came up as producing nothing, zilch. I brought the car home and popped the hood - Following the connections from the alternator with my hand, I ended up moving one connection slightly and there was a huge spark/short! The plastic connector had broken and the wire was not making a good enough connection to transfer the power produced by the alternator to the car. After fixing this connector, the car shifts PERFECTLY. It has been about a month and the problem has not come back. I guess since the alternator was not providing a consistent voltage to the car's electronics, the computer was sending mixed signals to the transmission.
After thinking the worst, it was refreshing to find out that the transmission problem was all because of a loose connector coming from the alternator.

I don't have any pics of the connector or anything else, but wanted to at least take a few minutes to post what I found - I got frustrated following posts that had no solution and thought this might help. I didn't see this solution posted anywhere, and it might be one of a couple things that cause this sort of "transmission shifting problem."
 
#69 ·
Hi Guys.

Thanks to these posting I have solved my Trooper 2000 transmission problem, and I wanted to post and share it with you. 3 dasy ago, the transmmision pf my tropper was "bumping" from 2>3 and backwards when stopping. After taking to the machine shop and receive quoatations for rebuilt transmissions at a prohibited cost, I went under my trroper just to find out that the wires from the senson were totally burned up, this was causing the fail. I replace the wires and taped with electrical tape and the car is like new again.

Thanks to all of you!!

Regards from Mexico!!!
 
#70 ·
To anyone who knows about this range mode sensor/park neutral safety switch causing the hard shift problem:
I have been having this problem for the past 6 months and after reading a lot of forums I am convinced that it is this sensor. I have taken the old one apart cleaned it and put it back & yet the problem still continues. So i decided to stop being cheap and I bought the new part from autozone for $100 and replaced it. YET my problem still hasnt gone away.

My question to everyone is: is there a specific way this part must be installed? I notice there is a small alignment hole on the sensor itself. I am convinced it is this sensor causing the problem because like everyone else states in their posts my dash lights are not corresponding with the correct shifter lever position. I.e when it is in drive it may say drive, but sumtimes when in park or reverse it may indicate neutral

I greatly appreciate any help on this issue
Feel free to email if necessary at nebel777@yahoo.com
 
#72 ·
being that i am an owner of a 2002 isuzu axiom 3.5 with transmission problems i found this sight and went through the posts on the mode selector switch being dirty could cause the problem i had problems with the shift cable locking ears broken off when removed which made the lights go crazy on p,r,n,3,2,1 no after market parts avable dealer item only i think 175.00 dealer only

my trans i tore it down second gear clutch hub burnt, and 3 gear hub burnt replaced them both replaced clutches and steels, rebuilt all clutch packs, front pump and went through valve body, replaced bost valve on valve body had great 1st and 2nd when 3rd, like slip and would slide in at ease very lazy, adjusted bost valve 3\4 turn, on valve body,testdrove 1st 2nd 3rd dr and od within 15 feet then stoped pulled out like stall speed converter 2 tho rpm to pull out like stuck in 3 rd gear i have no codes or any thing any ideas help
 
#74 ·
The Range Mode Switch ("sensor") is operated by a shaft that penetrates the transmission case. There is an oil seal around the shaft that will leak AFT when worn. The Isuzu/Honda part number is 8-08644-709-0, about $6.00 USD.
 
#75 ·
Thanks Buster28. When I pulled off the range sensor I discovered there was no seal. Or it wasnt on any longer. So I placed the seal and put everything back together. But seems as though its still leaking. now from the trans pan gasket. So I'm going to replace that again and put a little liquid seal to seal any spaces. I was wondering if anyone knows the tension to tighten the bolts to on the pan?
 
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