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AW-4 problem scary noisy

diesel-xj

NAXJA Forum User
Location
texas
hi all. I am pretty sure I toasted my AW-4. the jeep has 125k miles. it was running good with not leaks. I was coming to a stop the other day , and I put the trans in Park a little sooner than the jeep wanted. there was a pretty loud clunk and another noise harder to describe. I know you really are not supposed to do that. Well I did not think much of it, because I have done worse in the past on other vehicles. and there was not immediate problems. Then a couple of day later, I got a couple of blocks from the house, and the tranny was slipping very bad and then a slam engage. I pulled into a parking lot and shut down. still no leaks. I tried to back out of the parking spot, and just a lot of slip, and then a slam engage, and then slip. The jeep seemed to go forward better, but a lot of slipping.
I tried to push the jeep out of the parking spot in neutral. NO GO. it moved but not much. I went to hook a tow strap to the jeep to pull it out of the space and tow it home, and somehow my GF was able to get the jeep to reverse and then drive the 2 blocks back to the house. The jeep will go forward , but makes a pretty good grinding noise while it is doing it.
I am thinking that I somehow damaged the parking section of the trans. I ordered a manual for the trans, and I am waiting for it to arrive.
I have enough jeeps now that I am thinking to do the trans overhaul myself. but maybe it does not need a complete overhaul, just parking parts

any ideas
thanks
 
You may have grenaded the parking pawl in the transmission. Time to drop the pan and look for chunks of death. Sounds like a new (used) AW4 may be in your future. I also have a 98 2wd. You might use this opportunity to convert your XJ to 4wd like I'm planning. It's a complete bolt on and you would need to replace your AW4 with a 4x4 verson anyway. It is not the same in the 2wd application.

If you're going to crack the case, then go with the full overhaul. There's no point in replacing some seals and bands or clutch packs. Do the whole thing or replace the whole unit. If there are chunks of metal in the pan, then there's no way to get around a full overhaul. I'm wondering if you blew the parking pawl and the trans is trying to be in 2 gears at once (which will make very bad noises). Are you getting a MIL (check engine light)? If you are, pull codes and see if they relate to the trans. Report back here if you have any.

FYI, used 2wd AW4s are harder to find but they're out there. I see used prices around $150 from time to time. There's not a high demand because they're 2wd.
 
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Hi first thing I checked was the fluid. it was a quart and a half low. So much for no leaks. The jeep is sounding better today. I have not road tested it out of the driveway but the grinding rub sound is much less pronounced ( I guess I wore that part off). I did get the rear wheels up and off, and checked the rear brakes and they look ok. I put the engine in gear with the brake drums off, and the noise is still present in fwd and reverse. but more noticeable in reverse.
Also interesting with the wheels and Brake drums off and the trans in Neutral. the Drive shaft will only spin in one direction. So if I am not mistaken that is a problem of some sort.
ON the used trans front. UPull it is $150 and the already pulled is $550 from another yard. Our upull it is not a easy place to work. I figure I would be lucky to get a trans out in a full day work. More likely 2 days. So to me I am leaning on the already pulled unit for the extra $400. or I can buy a 2001 xj with 230000 miles and a 5 speed for $2500. It is a 2 door. The '01 has a lot of new parts, but at $2500 That is paying all the money. plus the 400 miles round trip to get it
Is there any way to just check the parking sprag without a complete trans teardown????. The rest of the trans seems good

thanks
 
If I were you I'd pull off the inspection plate at the front of the tranny (rear of the engine) and take a look for chunks of metal from a possibly cracked flexplate. A cracked flex plate is not too uncommon, especially with some trauma, like quick jerky motion.

It's may also sound like hell at first and when a chunk or some chunks fall off it could smooth out. Not smooth out permanently...just until the whole thing grenades.
 
That is a good idea. I am now leaning on teaching myself to do the overhaul. I am hoping That the spare jeep will make it until the diesel conversion jeep can clear the lift on it own power. Then I can start the trans overhaul on jeep 1. So I am at a stoping spot on this jeep for a bit

thanks
 
X2 on the flex plate inspection, you might get lucky!
 
Look around for more used transmissions. If I recall the 97 and 98 transmissions were specific to each year only because the wire harness connector to the engine harness was different each year. Pretty sure 91-96 transmissions were all the same. In 99 I think the trans designed changed by putting the input and output speed sensors into the tail shaft.

When I had a aw4 in my 97 when it went the junk yards wanted $750 for one. I ended up getting a super clean 91 aw4 for like $150 and then swapped the shift solenoids and wire harness for the trans. It was super easy to do and saved me some serious cash.
 
I finally got back to this jeep after being away at work for very long time. long story short . There is a small amount of metal in the trans oil pan, along with what looks to be 2 very small roller bearings. There are also 2 unknown objects in the bottom of the pan, that are covered in grey sludge and grit. Are these magnets???

I am pretty sure I know the answer to my questions, but I will ask anyway. Is it worth re-building this trans? I think I can still get a used trans for about $500. I see rebuild kits on the net and in shops for about $2-300. But these don't seem to have any hard parts. I know I don't know exactly what is broken in there yet. But how much do the typical broken hard parts cost??

I have always wanted to teach myself to rebuild a auto trans. Time is a little critical now. I have another DD, but this was my best jeep. The Mercedes diesel jeep is only good for about 50mph before it death wobbles, and it is kind of crappy to drive.

So for someone who is a pretty good wrench, but has never been in a automatic before, How long would a rebuild with hard part repair take? What are my chances for success on the first try? Do you think I can rebuild with hard parts for less than $500. I am going to guess NOT as the soft part kit and a rebuilt Torque converter are going to be about $350 to start.

thanks
 
Only way to tell for sure is to take it apart. I spent $1000 just rebuilding a used 5 speed manual Nissan gear box, I reused one gear, one of two shafts and the housing, and bought good used parts to replace the rest. Spent 12 weekends working on it, and 8 weeks waiting for parts shipments. All depends on what was damaged. Most NAXJA-ers have just paid $125 to buy a JY guaranteed box and swapped it out and hoped the first one was good. What year is it?
 
Where in Texas are you?
 
Thanks for the response. I am in Port Aransas/corpus Christi area. The jeep is a 1998 2wd 6 cylinder
I was pretty sure it would be over $500 to do it myself, and it would take a good amount of time.
So my choice now is to find a wrecked 2wd AW4, or junkyard transmission. OR Fast forward the next diesel conversion, which will be a 2.2L Kubota diesel.

This last weekend I bought a '94 2 door xj with a ax15, for $300 it runs and drives, but the interior is really shot, and I think it has over 240000 miles. Hopefully it will be a good donor transmissions
I should start another thread for this, but maybe I can squeeze it in. I will need to put a 1994 2wd ax15 into a 1998 2wd AW4 jeep.
So far I think I will need to use the 1994 drive shaft, and cross member, and pedal assembly.
My big question is what to do about the speedometer. I believe the '94 will have a mechanical speedo, and the '98 has electronic speedo. So the '94 ECU/TCUwill be no help.
Can you put a electric speed sender into a '94 ax15????????

any help is appreciated
 
If I were you I'd pull off the inspection plate at the front of the tranny (rear of the engine) and take a look for chunks of metal from a possibly cracked flexplate. A cracked flex plate is not too uncommon, especially with some trauma, like quick jerky motion.

It's may also sound like hell at first and when a chunk or some chunks fall off it could smooth out. Not smooth out permanently...just until the whole thing grenades.


http://www.cherokeeforum.com/f2/found-way-see-crack-my-flexplate-before-removal-171945/
 
Yes there was metal in the pan. not a lot but enough. I looked at the trans rebuild manual. I think one of the thrust bearings cratered. I found some very small roller bearings in the pan. I tried to post some pictures, but I am not allowed.
As of now I am leaning towards putting this jeep next on the conversion list. I wanted to learn to rebuild an automatic. But. The conversion might be faster, and I already have a donor AX-15.
So this thread is pretty much closed, As I am pretty sure the AW4 is toasted.

As of today I have available for very very cheap.
1- renix 4.0L 6cyl that had a blown head gasket, but was running stored outside for 5 years now
1- 1996 4.0L 6cyl that never ran I am not sure what was wrong with it. stored outside 3 years
1 1976 Mercedes 300d auto trans that was working ok when removed stored outside
1 1979 Mercedes 300SD auto trans that was working ok when removed stored outside
1 1989 jeep XJ 2wd AW4 that was working ok when removed stored inside no TC
1 1994 jeep 4.0L 6cyl running now still installed in the jeep, 255000 miles

So if anyone needs any of these for parts PM me

thanks

all of the above are available and will be going to the scrap yard if nobody wants any
 
I may be interested in the XJ stuff. Are you just giving it away or what?

1994 4.0, what is wrong with the engine, other than miles?

Renix engine, how do you know the head gasket is bad, how bad? Does the crank still turn???

1- renix 4.0L 6cyl that had a blown head gasket, but was running stored outside for 5 years now
1- 1996 4.0L 6cyl that never ran I am not sure what was wrong with it. stored outside 3 years
1- 1989 jeep XJ 2wd AW4 that was working ok when removed stored inside no TC
1- 1994 jeep 4.0L 6cyl running now still installed in the jeep, 255000 miles
 
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