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i just bought a 2003 grand caravan, 3.8L, and im having some shifting problems. when accelerating from a complete stop, and when the transmission changes from 1st to 2nd gear, there is a shudder. it feels like the transmission is changing into 2nd, then back, then into 2nd, then back, then into 2nd, and it will finally change all the way and accelerate through the rest of the gears just fine. It is a violent shudder. no noises coming from transmission though. i have no check engine light on, and no codes. i have changed out the throttle position sensor with a brand new one, and cleaned the throttle body. i have changed the oil and filter in the transmission, and used the proper atf+4 oil, and filled to correct level. problem still persists. i got a bottle of lucas transmission fix, but that didnt help either. in fact, made it worse. right after i put the lucas in, i developed a new problem. now, when decelerating, and the transmission shifts from 2nd to 1st, the car shakes as if it was a hard downshift, and you can hear a "thud". so now i have both problems. i have double checked all the electrical connections including the input and output speed sensors, and the tcm wiring, everything looks good. I have ordered a new shift solenoid pack, and will change that as soon as i get it. does anyone have any ideas as to what else it could be????
 

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Hi Andrew, welcome to the forum.

These vehicles are happiest when the proper transmission fluid is used. We use ATF +4 transmission fluid. Although the owners manual says that regular dextron is ok in a pinch, I believe all of would say a resounding, No! Always service the transmission with an approved ATF+4 fluid.

So, perhaps the previous owner did not know this, or possibly brought it to a repair station that added the wrong stuff...
There are a host of reasons that you could be experiencing these symptoms but what rings out for me is that when you put stuff other than ATF+4 in, the Lucas snake oil, it got worse.

Now, if you were to drain the T-fluid and replace it, you would only change about 1/3 (about less than 4 quarts out of roughly 10.7 qts) so a transmission fluid change is really only a fluid dilution.

ATF+4 has a friction modifier in it to make the transmission shift smoothly.

Some folks will recommend adding a friction modifier made for gear oil for use in rear wheel drive axles.
I do not believe that is what I would do to love my mini, but there are some that swear it has worked great. How long it is going to last, that would be my concern. What is that stuff going to do to the rest of my transmission components.
 

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i just bought a 2003 grand caravan, 3.8L, and im having some shifting problems. when accelerating from a complete stop, and when the transmission changes from 1st to 2nd gear, there is a shudder. it feels like the transmission is changing into 2nd, then back, then into 2nd, then back, then into 2nd, and it will finally change all the way and accelerate through the rest of the gears just fine. It is a violent shudder.

i have changed the oil and filter in the transmission, and used the proper atf+4 oil, and filled to correct level. problem still persists. i got a bottle of lucas transmission fix, but that didnt help either. in fact, made it worse. right after i put the lucas in, i developed a new problem. now, when decelerating, and the transmission shifts from 2nd to 1st, the car shakes as if it was a hard downshift, and you can hear a "thud". so now i have both problems.
So you changed the +4 once with a new filter.
That didn't work, so you added Lucas and it got worse.

Change it three more times. The filter should be OK to keep using unless you find it full of filth on the next swap/inspection.
Dorman makes a transmission pan with a drain plug in it for about $38, I got mine on Amazon.

What brand of ATF+4 did you use? See if your chosen brand is on this list:
https://www.centerforqa.com/chrysler-brands/

Do a good job of installing the pan for a leak free long lasting seal. Use a torque wrench. I use transmission RTV silicon by either Mopar or Permatex. Yes, there is a special RTV Silicon for use with ATF.

If you R&R the solenoid pack, make sure you get the right one, check the electrical connector for both shape and the same pins within the connector (likely flat blades, [vs round pins] for older transmission).
Some say that you need to do a quick learn procedure on the transmission computer after the solenoid pack change, other have said not so. If you can use the right scanner to do quick learn on the transmission, I do not think it is going to hurt anything to do it (even if half the folks say 'not required').

pLEASE Ooops, Caploc

Please return and tell us how it is going. Tell us what works and what does not. Let us know what finally fixes it or even if you just continue t drive it like it is.

AND, again, welcome to the Mopar MiniVan Garage.... The very best place on the planet to get information on you Chrysler, Dodge, Plymouth, DeSoto minivan!
 

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Discussion Starter #4
i just bought a 2003 grand caravan, 3.8L, and im having some shifting problems. when accelerating from a complete stop, and when the transmission changes from 1st to 2nd gear, there is a shudder. it feels like the transmission is changing into 2nd, then back, then into 2nd, then back, then into 2nd, and it will finally change all the way and accelerate through the rest of the gears just fine. It is a violent shudder.

i have changed the oil and filter in the transmission, and used the proper atf+4 oil, and filled to correct level. problem still persists. i got a bottle of lucas transmission fix, but that didnt help either. in fact, made it worse. right after i put the lucas in, i developed a new problem. now, when decelerating, and the transmission shifts from 2nd to 1st, the car shakes as if it was a hard downshift, and you can hear a "thud". so now i have both problems.
So you changed the +4 once with a new filter.
That didn't work, so you added Lucas and it got worse.

Change it three more times. The filter should be OK to keep using unless you find it full of filth on the next swap/inspection.
Dorman makes a transmission pan with a drain plug in it for about $38, I got mine on Amazon.

What brand of ATF+4 did you use? See if your chosen brand is on this list:
https://www.centerforqa.com/chrysler-brands/

Do a good job of installing the pan for a leak free long lasting seal. Use a torque wrench. I use transmission RTV silicon by either Mopar or Permatex. Yes, there is a special RTV Silicon for use with ATF.

If you R&R the solenoid pack, make sure you get the right one, check the electrical connector for both shape and the same pins within the connector (likely flat blades, [vs round pins] for older transmission).
Some say that you need to do a quick learn procedure on the transmission computer after the solenoid pack change, other have said not so. If you can use the right scanner to do quick learn on the transmission, I do not think it is going to hurt anything to do it (even if half the folks say 'not required').

pLEASE Ooops, Caploc

Please return and tell us how it is going. Tell us what works and what does not. Let us know what finally fixes it or even if you just continue t drive it like it is.

AND, again, welcome to the Mopar MiniVan Garage.... The very best place on the planet to get information on you Chrysler, Dodge, Plymouth, DeSoto minivan!



Thank you. I will change the oil again tomorrow to get the Lucas out. The solenoid pack is arriving next week so I will change the oil again then. We will se what happens. Thank you for your response. Oh and the +4 I used was the autozone brand on that list
 

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Although the owners manual says that regular dextron is ok in a pinch, I believe all of would say a resounding, No! Always service the transmission with an approved ATF+4 fluid.
Which manual? the one for the lawnmower?
Owner's Manual said:
Selection of Lubricant
It is important that the proper lubricant is used in the
transmission to assure optimum transmission perfor-
mance. Use only manufacturers recommended transmis-
sion fluid, refer to Recommended Fluids, Lubricants and
Genuine Parts for correct fluid type. It is important that
the transmission fluid be maintained at the prescribed
level using the recommended fluid.

CAUTION!
Using a transmission fluid other than the manufac-
turers recommended fluid may cause deterioration
in transmission shift quality and/or torque converter
shudder. Using a transmission fluid other than the
manufacturers recommended fluid will result in
more frequent fluid and filter changes. Refer to
Recommended Fluids, Lubricants and Genuine Parts
for correct fluid type.
Andrew.Bourke,
Assuming the trans service did not uncover any excessive deposits in the pan, you will have to get the additive out of the trans.
Unless you have a drain plug in the pan, get a siphon pump (or vacuum extractor) and when the trans is warm suck as much fluid as will come out of the pan (probably around 3-3.5 qts) though the dipstick.
Replace almost the same volume with new, certified ATF+4 right away (the fluid you put in will be cold and will expand) check the level before you go for next drive.

Repeat the above procedure after the van is driven 50-100mi.

In all likelihood, you will have to repeat this process 2 or 3 times before shift quality improves sufficiently.
If it does not show improvement after 3 fluid replacements and 40-50 "drive cycles", there's a problem with the trans...

When driving:
on acceleration, keep the RPMs near 2,000 - the more consistent you drive it the quicker the computer will be able to "re-learn" CVIs and improve shift quality.

A "bump shift" on 1-2 at light throttle (<1500 RPM) is characteristic of these (stock) gear boxes and does not indicate a problem. You can chase it all you want, it will get expensive and results are few and far between short of major modifications. (look up posts by Joel_B for best example)
 

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Which manual? the one for the lawnmower?
I spoke out of school.... In hindsight, I admit that I quoted hearsay to that point.
Somewhere in my travels I remember someone stating that was in a manual. [paraphrase here] that there was a blurb in a manual perhaps an earlier model when the A604 first came out, or around the time plus-3 or plus-4 fluid was introduced and not readily available.

I was thinking I could find that blurb on allpar.com, but it was not quite there and then, before I knew it, I got reading about CVT's

This internet is the devil...
...and Al Gore takes credit for it.


In further reading on that approved licensed ATF+4 site (Center for Quality Assurance) FAQ page, it is addressed about the recommended 3 fluid changes when other than approved fluid or an additive is used.
 

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Discussion Starter #7
Thanks everyone. Doing the first oil change this morning...... and when I changed the oil the first time, I found no metal deposits. Oil was clean, old looking, but clean.
 

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Good morning,

Here is a Mopar transmission 'rant' that is regarding the statement about the suggestion of the permissive use of Dextron in our transmissions. Where it comes from and why it is always a bad idea.

http://jerickweb.50webs.com/autobin/Chry_Trans_Tip.html

Very heavily weighted towards the use of +4 and how the use of anything other than the +4 will cause jerk, bump, and shudder. Also goes into DIY transmission transmission computer 'retraining' procedure. (I did this once, suggest early morning on desolate roadway. Plan on about an hour of complete stop and go driving)

Let us know how it is going Andrew.Bourke.
It is your feedback that helps us to help others.
Cheers!
 

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I can't help with the 'new' issue since you put the Lucas stuff in.

BUT, I CAN say that (as atoman said) a 1-2 bump shift, just as described, is common on our transmissions.
If the first couple shifts are OK (cold engine) it could just be an ENGINE programming characteristic (the fuel trim is too lean during warm shifts).

If the OP accelerates FASTER during the 1-2 shift, does it shift better than at a light throttle?
 

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Discussion Starter #10
I can't help with the 'new' issue since you put the Lucas stuff in.

BUT, I CAN say that (as atoman said) a 1-2 bump shift, just as described, is common on our transmissions.
If the first couple shifts are OK (cold engine) it could just be an ENGINE programming characteristic (the fuel trim is too lean during warm shifts).

If the OP accelerates FASTER during the 1-2 shift, does it shift better than at a light throttle?

carbuff2, you described the symptoms perfectly, its been cold in Georgia the last couple of days, and when i start the car up, and drive off no issues. once the car warms up, 1-2 bump shift!! also, under heavy acceleration, no bump shift. changes gears smoothly. but under normal to light acceleration, bump shifts every time.....
 

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my 2003 caravan also had this issue, so commonality is confirmed. It still did it at 443k miles when I sold it.
Defiantly change back to ATF4+.
 

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carbuff2, you described the symptoms perfectly, its been cold in Georgia the last couple of days, and when i start the car up, and drive off no issues. once the car warms up, 1-2 bump shift!! also, under heavy acceleration, no bump shift. changes gears smoothly. but under normal to light acceleration, bump shifts every time.....
Take a look at the front trans mount that's directly under the radiator - if you see the rubber isolator cracking, it's time to replace it. (cheap part and easy to do)
This mount takes most of the torque during shifting, when it starts to deteriorate the 'bump' becomes more pronounced...
 

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Discussion Starter #13
Dropped the pan and changed the oil. No dirt and oil looked clean. The motor mounts and transmission mount all look good. After the oil change, problem still exists. I did disconnect the battery for an hour, and then follow the steps to “retrain”, but still have the problem.......
 

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There's no "relearn" procedure, there's a "quick learn" procedure that requires a DRBIII (compatible) scan tool.
Unless TCM is re-programmed via scan tool, it takes many (on the order of 30+) drive cycles to adapt to the "CVI" values of a particular trans (from defaults) or an abrupt change in performance (part replacement or fluid modification).

There's no need to drop the pan for every fluid change, only for filter service and inspection of magnet...
 

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Discussion Starter #15
There's no "relearn" procedure, there's a "quick learn" procedure that requires a DRBIII (compatible) scan tool.
Unless TCM is re-programmed via scan tool, it takes many (on the order of 30+) drive cycles to adapt to the "CVI" values of a particular trans (from defaults) or an abrupt change in performance (part replacement or fluid modification).

There's no need to drop the pan for every fluid change, only for filter service and inspection of magnet...
10-4. I only dropped the pan because I have no way to get it out through the dipstick tube. And I wanted to get out as much of the Lucas transmission fix as I could. So is everyone thinking I need to have the van reprogrammed?
 

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Read that link I added in post #8.

It really does outline what is believed to be your situation, the reasoning to change the T fluid at least three times after contamination with anything other than +4 and a little something about a possible technique to self reprogram the TCU by driving.

If you can get access to a good professional scanner like some SnapOn or something that will address the TCU, you could program a quick learn.
Didn't you say you had plans to change the solenoid pack? If so, wait to 'quick learn' until after (perhaps it was another broke transmission post planed on changing the solenoid)

The answer to your question... There is not likely anything you can do to give you instant results. Be patient. Drive about 50, 100, or 250 miles and change the fluid again, and then a third time.
You only changed about a 1/4 to 1/3 of the transmission fluid. It is going to take time for the new, clean, slippery fluid to soak into the clutches, to get into all of the minute cavities, and passageways.
 

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Lipo suction...
Like the old spit sucker at the dentist office.

Get a 5 gallon pail and sealing lid. Cut two holes in the top. One big enough for you to plug your wife;s vacuum into. The second hole about the size of the stiff hose you bought at Home Depot dentist supply section that will fit down the dipstick tube.

Get a stiff hose like polypropylene about 5/16" ID -OR- get a 3 foot length of 1/4" copper tube and a hose that will attach to it.

Here is the tranny sucker build:
You are going to create suction on the top of the sealed pail with your betrothed's Hoover, Shark, Dyson... any old vac should do.
You are going to punch a smaller hose hole away from the suction device. We are really trying to not get the vacuum to inhale the fluid.

Insert that hose through the top and down about 1/2 way, this should keep the T fluid down low but not all the way to the bottom.
[we plan on sucking about a gallon of fluid] We don't want the bucket inlet (slop) hose to be below the fluid level or we'll make bubbles and get you divorced for doing something unpleasant to the Roomba.

TEST and adjust: If the vacuum is too strong, it will collapse the 5 gallon bucket. You may need to cut a vent hole or two to allow some air in to stop this from happening.

You can test try this contraption by sucking water out of the toilet, the dog bowl, bird bath, etc.... you get the idea.

IMG_1048 is the pic of my slop sucker. The hose on there is way to big for what you want. You need to have room for air to go into the dipstick tube while you are pulling fluid out with the likes of a drinking straw.

I used that hose/bucket to clean my autopsy table when it was getting all sloppy. See IMG_1042 for autopsy tray.

The other pix are for those of you who have not seen the inside of a transmission before.
My biggest recommendation: work clean, like a surgeon. The smallest bit of crap gets in there and finds the wrong spot, you are going to be very unhappy...

Let me know if you build this. Comments...?
 

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10-4. I only dropped the pan because I have no way to get it out through the dipstick tube. And I wanted to get out as much of the Lucas transmission fix as I could. So is everyone thinking I need to have the van reprogrammed?
No, not reprogrammed, you need to exchange most (90+%) of the fluid.
IIRC, the trans, TC, plus cooler contain close to 12qts of fluid (thus at 4qts per pan drop it takes about 3 drops to get most of the way there).

If you don't want to wait for incremental changes, you can flush the trans via cooler lines - by running the internal pump (there's a thread around of how to do it - just make sure it doesn't run dry). DO NOT perform a "power flush", weather it be pressure or vacuum.

Quick Learn may improve shift quality initially, but with contaminated fluid it will likely revert to shudder / harsh shifts because the fluid is out of spec for the computer control algorithm...
 

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Discussion Starter #19
Ok guys, I have changed the transmission fluid 4 times now. Not 3, but 4 times. Drove it at least 300 miles between changes. Used approved atf+4. As well as successfully changing the shift soliniod pack last weekend. Everytime I changed the oil, I disconnected the battery so the transmission control unit will revert to learn mode. Still not sure if this is a thing. But did it anyway. Some people are saying that doesn’t do anything, some people say it does. Anyway, STILL have shifting problems from 1st to 2nd. STILL shudders. Anyone have any other ideas without changing out the transmission. I can buy a rebuilt transmission and do it, but would rather not.
 

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If it's the typical 'bump shift', you can live with it (shifting to '3' might help some in heavy traffic), pull the valve body and check L/R accumulator and seals (or get sonnax or similar retrofit kit) - this is hit or miss at best, or get a jasper trans...
 
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