Please help with Grand Cherokee transmission

I want to apologize up front if this is a common post, but I have read and searched for a long time and still do not know where to start. My little brother has a 2wd 1996 Grand Cherokee Laredo with a 4.0 6 cyl. and approximately 190,000 miles on it. The Jeep was running fine until the radiator line (bottom of rad) that connects to the trans busted. He swears he didn't drive it for very long at all after he realized that the line has broken and he had lost fluid. We put a new rad in and refilled the fluid (checked the trans in neutral on a flat grade after it had warmed up). On our first test drive everything seemed fine. But right after that the truck refused to shift into overdrive. We parked it and triple checked the fluid levels (used Dextron III I'm pretty sure, can't remember, but pretty sure). Fluid levels are still showing in operating range. Now the truck will not shift at all, like it is stuck in neutral. I am having him disconnect the battery as we speak in an attempt to reset the electronics. I really hope that he doesn't need to rebuild the tranny, because he can barely pay for the truck, and my tax refund is desperately needed elsewhere. Does anyone have any idea what and where I should start next? Any help is tremendously appreciated and I am sorry for the long post.

well don't use dextron 3, use ATF 3+. Sits like it is in nuetral. Try moving in all gears (i imagine you did this). PUt the four wheel drive in nuetral and then engage it again. Other than that, have it looked at. Usually has to do with pressure inside the tranny, not so much on the gearing.

This is one of those issues that seems to get a lot of varied answers and I for one wish there were some definitive information on the subject.

I've seen plenty of posts stating the dire consequences of using anything but ATF +3 yet my own original 1993 owners manual states on page 4-27 Mopar Mercon/Dexron II is preferred. ATF + Type 7176 may be used for top off.

YET on page 4-29 "It is important that the proper lubricant is used in the transmission. Mopar ATF + Type 7176 or equivalent should be used to aid in assuring optimum transmission performance. Fluids of the type labeled Dexron II ATF should be used only if the recommended fluid is not available."

Atf+4 must always be used in vehicles that were origionally fitted with Atf+4.
Atf+4 is compatable with Atf+3, Atf+2. Atf+4 can be used to top off vehicles with Atf+3 and Atf+2. But Atf+3 and Atf+2 can not be used to top off vehicles with Atf+4..Note Mopar does not reccomend Dexron 1,2or3, to be used in any Mopar vehicle that uses Atf+2,3,4.

So I'm guessing that I should start with changing the fluid then? I sure hope that it is something that easy, the fluid and filter probably needed changing anyway. I need to read now on how to get all the fluid out instead of just what is in the pan.

Check and see what trans you have first.
Some cry/jeep used the Aisin Warner -4 AW4
The big long almost square type oil pan.
If it is the AW4 trans they take dexron fluid not the cry fluid
MT
Also a little info on.
To Flush or not To Flush ?
Just like Kenney Rodgers said you have got to know when to fold and when to hold.
If the fluid has high mileage 100K or over or is real dirty you had better hold.
On a trans that has had good regular service at 50K or sooner a flush is good.
But be ware of jiffie/quick/wallmart /fast lubes that offer power and fast flushes.
They have abused and over rated the trans flush.
They have a habit of using one fit all fluid out of the same barrel that fits all.
They just throw in a bottle of additive to make it fit all. Or worse they pitch in a bottle of cleaner or dope in it that can do more harm than good. And will tell you the filter does not need changing with a flush.
Just remember that all new fluid makes a high detergent cleaner that will break loose all varnish and dirt and grit in the trans and drop it in valve body and solenoids.
Always change the filter and go easy on or use no dope and cleaner.
Adjust/check the bands and linkage on the trans that have bands and adjustments.
Always use the trans fluid the trans/manf calls for. And be aware that some manf have changed the type of fluid specs since the trans was manf.
Some fords have changed the specs and a lot of cry/dodge have gone to the newer type of fluid on their trans service.
Also some fords have tsb’s and require a total complete trans flush to cure trans shifting problems. Some as low as 30K
If a person does not have a flush machine a old 5 gallon bucket and a couple of rubber hoses to connect to the cooler lines and with the other end in the bucket will make a good flush machine. Just put the hoses in the bucket and start the engine and start pouring fluid into the trans until the fluid running into the bucket gets good and clean.
It usually takes 16-20 qts. To get a good flush.
Flush or No flush always service the trans filter and trans on a good regular basic.
People that keep the serviced have a lot less trans problems.

This is one of those issues that seems to get a lot of varied answers and I for one wish there were some definitive information on the subject.

I've seen plenty of posts stating the dire consequences of using anything but ATF +3 yet my own original 1993 owners manual states on page 4-27 Mopar Mercon/Dexron II is preferred. ATF + Type 7176 may be used for top off.

YET on page 4-29 "It is important that the proper lubricant is used in the transmission. Mopar ATF + Type 7176 or equivalent should be used to aid in assuring optimum transmission performance. Fluids of the type labeled Dexron II ATF should be used only if the recommended fluid is not available."

Does it have the Aisin Warner-4 AW4 trans in it?
If so they call for Dexron fluid istead of cry fluid.
MT

My build sheet says the vehicle came off the line in Aug of 92, and I have the AW4. For others though they have to check to see what they have. Mid year the transmission was switched to the 42re.

Here's an example of why I scratch my head over all this.

http://www.allpar.com/fix/trans.html

Assuming that I do have the wrong fluid in it, won't I have to flush it to get the old fluid out to replace it with the correct fluid?

I had a very Similar experience with my '97 JGC, 4.0, 2 wheel drive. Cooler line at radiator came off and wife drove it about 1 mile before noticing it. I put the line back on (with double clamps this time) and put 8, count 'em, EIGHT quarts of Dexron III in it. Then I realized it's supposed to have ATF+4. Closest I could find was Castrol ATF+ (label said it was compatible) and changed the fluid. Ever since it lost the line, it buzzes like a gang of angry hornets, in DRIVE it can't make up it's mind what gear it wants to be in, slipping, and when warm the converter won't lock up in overdrive. Dealership says I have a 42RE trans, and they can order one for me for 'about $1500'...that is, of course, not counting shipping and labor if they R&R it. I have found a '95 identical to mine, does it have the same 42RE as mine?