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96 aw4 no reverse, od, and running hot on Interstate speeds

Eerielayne

NAXJA Forum User
Location
Georgia
Alrighty, I'm new to the world of jeeps as of a few weeks ago. Funny enough I'm also brand new to automatic transmissions (just as I get a vehicle with transmission faults). I want to preface this by saying that I have no CEL and I scanned the computer to be safe and there is nothing pending or posted. I bought the jeep with no reverse for $900 and it happened to have a problem with overheating on the highway (anything over 45mph would overheat it). I treated the problem like I would any other overheating scenario, flush, thermostat, Rad cap, then radiator, then fan clutch and water pump :mad: after doing the water pump and fan clutch the overheating issue seems to be resolved, however it still runs hot if I'm going speeds of 70+mph (around 230°). I looked over the whole cooling system again and checked for leaks or anything signifying that I did something wrong. After this I got to thinking outside the box and read around about peoples rpm on the highway, at 60mph I sit at 3000 rpm and at 80mph I'm at 4000rpm, APPARENTLY that's not normal. If you've read this far, I apologize but I wanted to get my whole story out to prevent any misleading. I know very little about automatic transmissions as I've always owned manuals, so I don't know where to look for the problem. After tons of research for several days I can't really find anyone with my same exact issue. Keep in mind I have no CEL! Thanks for reading!

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Really need to know the year and engine.

Before you go any farther with the cooling system squeeze the bottom radiator hose and make sure you have a spring inside of it. It can collapse (or partially) without that spring at higher RPM's.

Pull off the radiator cap when cold let it warm up, some coolant will flow out the top as it heats and expands (normal), put a catch pan underneath you likely won't lose much, flush the area with clean water when you are done. Look to see if any bubbles are coming to the top after the coolant level stabilizes and it is at operating temp.

Sometimes the radiator is partially plugged a flush may not get it all. The top radiator hose being rock hard (with the cap on and the system pressurized) and swollen, when you rev the motor, is an indicator you have flow restriction.

Sounds like your tranny may have some solenoid issues or solenoid wiring issues. Could be it is toast, but there are some sensors that affect lock up and shifts, but not reverse. It pays to check and test before you go looking for a new tranny. Shift linkage may be an issue, though it doesn't mess up often.

Does it start OK in P and N and not in any other gear?
 
Sorry I missed the year in your post title, still need the engine.

When my 96 lost reverse the trans was junk, I had a pile of metal bits and pieces in the pan. I never did get the whole story but apparently one of my daughters shifted into reverse or park at 50 MPH and broke some serious stuff.
 
Sometimes the restriction is on the face of the radiator. Check for dust leaves etc blocking air flow across radiator.
 
If the tranny is slipping or having issues it can throw a ton of extra heat into the radiator. OD can be caused by a faulty brake switch or wiring.
 
You do know to check the fluid level with the engine running and after you have shifted between gears while parked on a level spot? You said you were new to automatics. :)

Also check the fluid color and smell. Straw colored (to dark brown) fluid that smells burnt is an indicator.
 
No reverse means your trans is bad. That has nothing to do with the TCM control. The heat is probably from slippage sinec its a toasted trans. Never seen an AW4 trans just magically start working after you get to the no reverse stage.
 
Sorry for the late response, I thought the aw4 was only in the 4.0, however that's what I have. As said I've replaced everything in the cooling system and it has been properly burped so I highly doubt its the cooling system, I just added it for history. And it starts just fine, though it could use a new battery. The tranny fluid is burnt to shit, even after replacing it which is what's led me to believe it's the transmission itself, but I'm not familiar enough with automatics to really say do for sure.

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You do know to check the fluid level with the engine running and after you have shifted between gears while parked on a level spot? You said you were new to automatics. :)

Also check the fluid color and smell. Straw colored (to dark brown) fluid that smells burnt is an indicator.
Haha and yes I know the basics of it, but cant troubleshoot one as you can tell

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Sorry for the late response, I thought the aw4 was only in the 4.0, however that's what I have. As said I've replaced everything in the cooling system and it has been properly burped so I highly doubt its the cooling system, I just added it for history. And it starts just fine, though it could use a new battery. The tranny fluid is BURT TO SHIT, even after replacing it which is what's led me to believe it's the transmission itself, but I'm not familiar enough with automatics to really say do for sure.

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the burnt to shit part usually tells that the trans is hurt bad, if not a total goner. I'd start poking around the junkyards for another aw4. I had a 96 4.0 4wd that burnt the fluid. That thing would overheat and slip and shift super late. Had 400,000 and change on the clock. When you go looking for a trans the fluid tells the what condition it's in. If there's none pull the trans line and get fluid from it. Bright purple to pink is perfect. It can be a bit dark but stay away from burnt or you will back to square one. Good luck.



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the burnt to shit part usually tells that the trans is hurt bad, if not a total goner. I'd start poking around the junkyards for another aw4. I had a 96 4.0 4wd that burnt the fluid. That thing would overheat and slip and shift super late. Had 400,000 and change on the clock. When you go looking for a trans the fluid tells the what condition it's in. If there's none pull the trans line and get fluid from it. Bright purple to pink is perfect. It can be a bit dark but stay away from burnt or you will back to square one. Good luck.



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So it would be safe to go ahead and just replace the transmission? That was the plan initially I just didn't want to buy a transmission and go through the effort of swapping it if it may not fix the problem. Thanks all!

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So it would be safe to go ahead and just replace the transmission? That was the plan initially I just didn't want to buy a transmission and go through the effort of swapping it if it may not fix the problem. Thanks all!

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If your cruising down the highway and you shift to 3rd and it doesn't rev up then you have no od. In town less than 35 shift to first and it should rev way up. Close to 4000-4500. Click it to 3 rd and step on it. Before you stomp on it be sure to be ABOVE 37 as it will probably shift back to first if you go to the floor. If it revs up but not to the red line then you have 1,2 and 3 but no od or reverse. The no reverse part to me would say the trans is garbage. Never seen one come back without a full and complete rebuild. Not worth it IMO. Just get a used one from a yard or cl. Good luck is your findings. Another thing to check is the shift linkage. Yes, one tooth makes a world of difference.


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If your cruising down the highway and you shift to 3rd and it doesn't rev up then you have no od. In town less than 35 shift to first and it should rev way up. Close to 4000-4500. Click it to 3 rd and step on it. Before you stomp on it be sure to be ABOVE 37 as it will probably shift back to first if you go to the floor. If it revs up but not to the red line then you have 1,2 and 3 but no od or reverse. The no reverse part to me would say the trans is garbage. Never seen one come back without a full and complete rebuild. Not worth it IMO. Just get a used one from a yard or cl. Good luck is your findings. Another thing to check is the shift linkage. Yes, one tooth makes a world of difference.


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Yeah definitely don't have od, I'll just go buy a tranny and do that. Local yard has several for 250 a peice



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