To change the tranny fluid or not to change the tranny fluid...

atfrith · Dec 20, 2004

hey guys, i just got my XJ back from the mechanic after a couple days, i had some dieing, sputtering issues and also a broken water pump and serpentine belt. Lately i've been having some little tranny slipping issues, where if i just push the gas on a hill or straight away to keep my speed, the RPMS will go up like normal when i step on the gas but then immediately drop down, and then it takes quite a bit of throttle to get back into gear, i dunno whats wrong, but its not tooo bad. I asked thhe mechanic what i should do and he told me that no matter what do not let ANYONE push me into flushing the transmission or changing the fluid, cuz it could loosen stuff that isn't lose right now, in otherwords, if its not broke don't fix it. But i was just doing a search about flushing the tranny and came across quite a few threads whhere people say theey change their tranny fluid very often and i had some people tell me that maybe a fluid and filter change would make my shifting better. I have 117K on it now, 1990, AW4 auto. I'm not sure if the fluid has ever been changed or not. What should i do?

__________________

5-90 · Dec 20, 2004

I guess the key question at the moment is "What colour is the fluid?" If it's still red, then perhaps a change is in order. If it's anything else (usually brown, worst case would be black) then a change is DEFINITELY in order!

The problem you have is that in an automatic, there's isn't just the one clutch like in a stick. The AW4 has (IIRC) 24 clutches in it, and they are all "wet" clutches - which therefore depend upon having fresh fluid. Why? There are detergents and friction modifiers in the fluid that break down over time, and they will impair the function of those clutches (not to mention the varnish and crud that can build up in the valve body and control passages and cause you headaches - shifting problems, sticking, sluggish response, and the like.)

Given the typical automatic transmission, if I don't know what sort of maintenance it had before I got it or rebuilt it, or if it's acting just a little hinky, I'll flush it with something like Berryman's B12 Chemtool and refill. It really can't hurt anything (most of the stuff that can build up will liquefy in solvent) and it just might help. Automatic transmissions are picky creatures...

5-90

Ray H · Dec 20, 2004

Just a simple fluid and filter change isnt going to loosen anything. All that you will be doing is dropping the pan and the fluid thats sitting in there and putting the pan back up with new filter and topping off the fluid. No harm done there and it will give you an opportunity to see what your fluid and filter look like.
I agree with him that a flush is probably a bad thing at this point.
Im no tranny expect by any stretch but it doesnt sound as though a fluid and filter change is going to help your specific problem.
I would look at the throttle cable adjustment first, its easy and inexpensive.
Lets see what the experts have to say.

atfrith · Dec 20, 2004

Actually somebody else on a different board said to adjust the throttle cable as well. Where exactly is it and how do i do it? And basically everybody else on the boards said the same that a fluid and filter change is good but not a flush. Its just that my mom was standing next to me in the shop when the mechanic said that, so now when i tel my mom i want to change the fluid she freaks out saying "THE MECHANIC SAID NOT TO DO THAT!", and ya, she really doesn't want me to do it, but whatever. Thanks for ur help guys

atfrith · Dec 21, 2004

anybody? Before i change the fluid and filter i wanna check out that TV cable adjustment but i can't find my Haynes manual anywhere and my searching on the internet yielding nothing..

94XJ4x4 · Dec 21, 2004

I assume you mean TB cable? I may be missing something here though.... Im not quite sure where you adjust it (i have never done it before) but pop the hood and take a look it probably isnt that hard to find. before i changed my transmission fluid when i stopped then tried to accelerate again (like at a stop sign) my transmission would slip. Has this been happening to you? It seams weird to me that your RPM drops when applying the accelarator. if it was your transmission comming out of gear wouldnt your RPM climb faster... not drop? You may want to plug it into a scan tool. It may help point you in the direction of the problem. Sounds like the transmission fluid needs changing though anyway. I cant remember at what mileage i changed mine at but i think it was around 120000. Although, Im fairly sure it had been changed at least once before that.

atfrith · Dec 21, 2004

i'm pretty sure what they meant was TV, throttle valve cable, but i'm not 100% sure. But no, it doesn't really do it like from a stop sign, thats like the only time it doesn't do it, wen i'm giving constant gas. It happens after i push the accelerator and when i'm trying to keep the accelerator at one spot to maintain my speed, thats when the RPMs drop, when i'm keepin the speed at a constant. then when i try to climb outta that speed it takes a little more gas than i would think neccesary and sometimes it feels like it kinda jumps back into gear.

nate · Dec 21, 2004

Yeah its TV.

Tranny should be changed every 12k according to my Jeep manual... just something to think about.

crazyoffroader · Dec 21, 2004

nate said:
Yeah its TV.

Tranny should be changed every 12k according to my Jeep manual... just something to think about.

That could get expensive real quick! I think you ment tranny fluid, in which case, yes.
As for the manual, it it haynes book #50010., but it doesn't tell how to adjust the cable, or even that there is a cable from what i can see in the book.
HTH

atfrith · Dec 21, 2004

Ya i think i'm gonna change the fluid and filter here pretty soon, does anybody know where to get a filter and about how much they cost? And i was thinking about the TV cable thing, is that just the cable that goes fromthe accelerator to the throttle body?? the one that when u push the pedal it opens up the tb?

motorcityxj · Dec 21, 2004

Not sure there is a magic answer to your problem, but i think this don't change the fluid , or don't flush it is only gonna help you get a few more miles out of the tranny till it craps out. If everything was in good order a tanny flush simply gets all the fluid thats sitting in the torque converter, that otherwise would linger there and you would only get 2/3 of the old fluid out. If the jackhole doing the flush don't somehow (i don't know what they would do wrong?) mess it up getting all nice new high quality fluid CANNOT be a bad thing.

If how ever your tranny has been abused for years and is on its last leg this flush might not be the cure your looking for ... but instead send your AW4 to the big junk yard in the sky a few months quicker than if you just left it be in its fragile state.

scoobyxj · Dec 21, 2004

First acording to my local Chrysler dealer it's inpossable to get the fluid out of the torque converter unless it is removed from the tranny and has a hole drilled in it to drain it. The TV cable is conected to the throttle body and runs down to the tranny. There is a little button like thing on the bracket that the cable goes threw by the throttle body. Push the button down, and rotate the lever on the side of the throttle all the way open, release the botton, and then the lever. That should set it back to the factory position. From your origanal post it sounds like there is nothing wrong with it though. When you let off the gas then reaply, the torque converter will come unlocked [seaming like a down shift] then lock back up, within a second or so. If it where mine and it seames like somthing is amiss I would go to a very reputable tranny shop and have them take it for a drive. They should do it for free, and if there isnt anything wrong with it, maby have them do a flush to justify there time.

Starboard M · Dec 22, 2004

Are you sure it has enough tranny fluid in it?
Reason Im asking is I blew a tranny line going through a mud pit, and didnt know it. Got to the end, and couldnt get up the last little incline. Even though I was flooring it, I was slidding back. Didnt know what was happeing. Turns out I had no fluid in the tranny. Replaced the line, put in more fluid and it was fine.

So basicly, make sure there is enough fluid in the tranny before you get it flushed.

XJJPR · Dec 22, 2004

scoobyxj said:
First acording to my local Chrysler dealer it's inpossable to get the fluid out of the torque converter unless it is removed from the tranny and has a hole drilled in it to drain it. The TV cable is conected to the throttle body and runs down to the tranny. There is a little button like thing on the bracket that the cable goes threw by the throttle body. Push the button down, and rotate the lever on the side of the throttle all the way open, release the botton, and then the lever. That should set it back to the factory position. From your origanal post it sounds like there is nothing wrong with it though. When you let off the gas then reaply, the torque converter will come unlocked [seaming like a down shift] then lock back up, within a second or so. If it where mine and it seames like somthing is amiss I would go to a very reputable tranny shop and have them take it for a drive. They should do it for free, and if there isnt anything wrong with it, maby have them do a flush to justify there time.

I don't want to retype it so I'll just agree with the above!

hinkley

Ray H · Dec 22, 2004

atfrith said:
i'm pretty sure what they meant was TV, throttle valve cable, but i'm not 100% sure. But no, it doesn't really do it like from a stop sign, thats like the only time it doesn't do it, wen i'm giving constant gas. It happens after i push the accelerator and when i'm trying to keep the accelerator at one spot to maintain my speed, thats when the RPMs drop, when i'm keepin the speed at a constant. then when i try to climb outta that speed it takes a little more gas than i would think neccesary and sometimes it feels like it kinda jumps back into gear.

How much of an RPM drop are we talking about?
After rereading your posts, Im going to have to agree with scooby on this (although I disagree about flushing it just so the tranny shop feels better). If its only a couple hundred RPMs then thats your torque converter locking up and its normal. It will unlock when you accelerate and then lockup again when you reach your desired speed and let off the pedal.

From your first post, I was under the impression that it was shifting erradically when you accelerated.

The transmission throttle cabe adjustment is free and only takes 2 seconds so it wouldnt hurt. If it was out of adjustment, it will feel like a whole new tranny.

Sarge · Dec 22, 2004

scoobyxj said:
First acording to my local Chrysler dealer it's inpossable to get the fluid out of the torque converter unless it is removed from the tranny and has a hole drilled in it to drain it.

Actually a flush is very possible now. There is a machine that hooks up and pumps new in and old out until it's all fresh. It aint cheap, running in the area of $100. I know a few folks who have done this and none have had a single problem. One barely drives the thing and the other puts well over 150 miles a day on is car.

Sarge

mikeny59 · Dec 22, 2004

NAPA filter kit and continually flush...

http://www.napaonline.com

NAPA filter kits are a good deal, my '98 has a steel mesh element that can be cleaned, I opted to replace it though. About $30 for element and gasket.

When I bought my '98 new, after break-in mileage, I changed all possible fluids and greases to Mobil 1. I know everyone says that tranny doesn't take kindly to synthetic fluid, especially a high-mileage one like yours, but that's not the point.

If you want to near 100% percent new fluid, change the filter and fluid, drive it around some and keep doing it again until all the old stuff is gone.

I forget the math that tells you how many changes nears 100% of new fluid, but it involves total tranny capacity vs. how much drops each time from the pan. It can get expensive.

In my case, with Mobil 1, it got very expensive, but after 98k I've had zero tranny problems that other posters have mentioned. I also have to remove the crossmember and tranny fill tube to drop the pan, I don't if that's the case with your year.

Good Luck.

Mike/NY #300

scoobyxj · Dec 23, 2004

Sarge said:
Actually a flush is very possible now. There is a machine that hooks up and pumps new in and old out until it's all fresh. It aint cheap, running in the area of $100. I know a few folks who have done this and none have had a single problem. One barely drives the thing and the other puts well over 150 miles a day on is car.

Sarge

Yes that is what is in mind when the service intervial [sp] calls for a 100k till a filter change. But the fluid still stays in the torque converter, all but whats left in the converter is changed. [Acording to the dealership] and I'm going to say around $130 maby $140 for a flush & filter. I had this done over the summer and will never do a change myself again. I mean think about it they can get say 90% of the fluid out vs my maby 20%. Well worth the money in my opinion. Proper maintaince is key to tranny life. I got 180k out of a Caravan 4speed auto before the clutch lining fell of the torque converter [the tranny was still good] and rebuilt it. Thats just insane milage for a tranny with a reputation of just 50k/70k!

atfrith · Dec 23, 2004

thanks a lot for all the suggestions and help guys. I'm gonna try and check that tv cable tomorrow as well as give that mechanic another call. But after reading these posts i think it may just be the torque converter locking and unlocking. Its just that it seems to do the "downshift" thing while i'm still on the gas, when i'm trying to maintain my speed by holding the pedal at a constant level it will drop a few rpms like its downshifting, and its not like i can simply give it a little more gas to get it back into gear, i have to give it quite a bit. Someone mentioned the tranny fluid level, well when i first brought it to the mechanic to fix my waterpump he said i was low on tranny fluid, and he added more to it, so the level is fine now. But ya i'll check the TV cable and everything tomorrow and give an update. Thanks a lot

NotMatt · Dec 23, 2004

My brother's comanche is currently behaving like this. When trying to keep a constant speed on the highway, the torque converter will lock and unlock repeatedly when I'm almost sure it shouldn't be. Feels like the truck lags for a second and the RPM's go up, then back down.

The two suggestions I have that were given to me are to check the TV cable adjustment, like everyone else said (hasn't fixed my brother's problem in his comanche though), OR test/replace the TPS. I'm not sure how it all works together, but I'm figuring that if the TPS has a funky spot in it, it could cause the transmission to think you're pressing the throttle more than you are, and make it want to downshift/unlock the TC.

Anyway, we're still working on the second suggestion, he's borrowing a TPS from a friend's rig (mine's a stick, so it won't swap over) that drives fine, and we're going to see if it fixes the problem.

To change the tranny fluid or not to change the tranny fluid...

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Member

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Member #300

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

Similar threads