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Transmission rebuild or replacement

Jeepmedic46

NAXJA Forum User
NAXJA Member
Location
Orange, Ma
My 2000 XJ sport with the 4.0. Transmission has 286,000 miles on it. Jeep won't go over 50 mph. Tach goes up to 4000 and isn't shifting. I'm thinking the transmission is finally going. Would it be better to rebuild or replace with a transmission and transfer case from the boneyard? How do I figure out what transmission and transfer case I have?
 
I suggest you test the solenoids and the Throttle Position Sensor first. Tried swapping in your spare Transmission Control Module ?

The only 4.0L auto transmission is an AW-4 and your transfer case has an ID tag on it .

Seen this ? >> https://www.naxja.org/forum/showthread.php?t=1053970
 
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First, I'd change the trans oil a few times, if you haven't changed it on a yearly basis. Next, check the fluid level. Dex/Mercon for fluid.
Next, I'd unplug the trans computer. You will need to manually shift. Also, it will not 'brake'. So, you will need to apply brakes, and get to the proper speed or RMP to down shift.
If this functions OK, then your issues are probably electronic. Check the Solenoids as suggested. There are about 5 or more sensors that control the trans. The solenoids, the two speed sensors, the TBS, the brake switch, the trans computer, the NSS (Range Selector for 98+), ECM. Also, could be an electrical issue. Check you battery. Then you might check voltage at certain locations.
As to 'junkyard' parts, it can be luck of the draw. I've had two bad motors from JY's. I did have a trans replaced this past year. I am selling off one of my XJs. So, I wanted to keep the trans I had rebuilt about 5 years ago. A guy who works on Jeep that I use had some AW4s. I had him swap in one. $100 or $200 for the trans and $200 labor. Yeah, cheap. Works good.
He did have another trans there last week. Looked almost new. No TC though.
 
My experience with JY purchases is that I am getting that exactly; "junk". Anymore, due to the age and high mileage of these things, I just plan on rebuilding whatever I purchase from a JY. At this point, I'm looking more for a "core" than a working representation of what I need.

Which means, unless I don't have the part (like in the case of wanting a NP242 instead of my NP231), I'll rebuild what I have.

And when I find a NP242, I'll at least open it up and thoroughly inspect it. But most likely I'll rebuild it.
 
My experience with JY purchases is that I am getting that exactly; "junk". Anymore, due to the age and high mileage of these things, I just plan on rebuilding whatever I purchase from a JY. At this point, I'm looking more for a "core" than a working representation of what I need.

Which means, unless I don't have the part (like in the case of wanting a NP242 instead of my NP231), I'll rebuild what I have.

And when I find a NP242, I'll at least open it up and thoroughly inspect it. But most likely I'll rebuild it.

I forget where I bought my 242 TC. I did open it up. The filter was packed.

For the OP, I did do a Search for the Boston/New England region on:
Car-Parts.com
There were several choices below 100K miles. Still, I think the one I bought was said to have about 100K miles. Outside looked meh.

Edit: Also adjust the trans cable, up by the Throttle Body.
 
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Looks like my transmission is shot. Place said they can rebuild it for between 2400 and 3500. Would it be cheaper to do a reman?
 
I looked at NAPA. Its $2200, plus core or $400. You also have to factor in that their price should include labor to replace. IE, in and out. I don't know what current prices are. And it might depend on vehicle. Who determined it was shot? What or why was it shot? My 2000 XJ has 270K on it. trans is still good.
Not saying yours is good or bad. Did you unplug the TCM and drive it? I think fuse #11 in the Junction Box is suppose to also disable the TCM.
 
2400-3500?!
There has to be hundreds of these things rotting away that people will sell for a few hundred bucks, grab another tranny and swap it in, its a 3 hour job in a gravel driveway with a harbor freight tranny jack and hand tools.
 
Brought it to Aamco and they did their testing on it and apparently I don’t have 3rd gear on it.

OK, you don't have a third gear. Why? Solenoid, speed sensor? For that kind of money, I'd do a few test. As said above, test the solenoids. If you have a Volt/Ohm meter, its not that hard.
Up by the oil dipstick, there are two connection plugs. One is black, the other a gray. One of those is to the NSS or Range Selector, the other to the trans. Disconnect the one to the trans. There should be 4 blades on the top and 3 on the bottom. The first 3 on the top are to the solenoids. You need to put the Meter to OHMs. Put on probe to the first blade, and the other to a ground. I used the bolts on the valve cover. It should read 10-16 ohms. Possibly try a few different ground locations, if you get no reading. I'd disconnect the Trans computer and see if it shifts OK manually.
 
2400-3500?!
There has to be hundreds of these things rotting away that people will sell for a few hundred bucks, grab another tranny and swap it in, its a 3 hour job in a gravel driveway with a harbor freight tranny jack and hand tools.

I was quoted £800 to rebuild mine several years ago now which I thought was a lot (probably about $1,000) & the same to swap in the trans from my parts XJ (although now know as it's a '96 it won't work in the '99) so I bought another XJ for not much more. Prices of XJ's have probably trebled since then, cost of a trans less so.

3 hours! I must've taken that long the 1st time to put it up on stands, drain the trans, remove the driveshafts & destroy the NSS.

The 2nd time I must have spent that much time just trying to remove the exhaust.

For us mere mortals, I would've thought 3 days was more like it, so I can't fail to be impressed.
 
Unfortunately I can’t lie on my back to replace the transmission. No one to help. You would think junkyards would be full but apparently not.
 
BTW, that was for a carry-in transmission only!
 
40yrs ago I had them trick out a trans (T350) for my Nova!
 
I almost forgot they also did a T400 for my Jeep J-10.
 
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