Tranny problem in Cherokee

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  #1  
Old 05-20-08, 06:14 AM
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Tranny problem in Cherokee

I have a 1996 Jeep Cherokee that I just purchased. The transmission has been acting a little strange.

Details: When first starting in the morning (or just when engine is cold) the jeep shifts into Drive and Reverse just fine. Also, when driving it shifts through gears just fine.

The problem is when it warms up and I shift from Park into D or R, there is a noticeable surge and creaking sound to go with it. It seems as though the jeep just wants to go by itself. Again, this does not happen when cold.

I checked the tranny fluid and is was WAY on the high side. Any thoughts??
 

Last edited by 2dirtydeeds; 05-20-08 at 06:15 AM. Reason: grammer
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  #2  
Old 05-20-08, 07:33 AM
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Just to confirm - this is a Jeep Cherokee (not a Grand Cherokee) correct? Contrary to what one would think, they have very different transmissions. The Grand Cherokee has a Chrysler trans and the Cherokee has an Aisin Warner trans.

- Joe
 
  #3  
Old 05-20-08, 07:35 AM
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Just to confirm - this is a Jeep Cherokee (not a Grand Cherokee) correct?
Yes, this is just a Jeep Cherokee SE. I am assuming it has the AW4 transmission.
 
  #4  
Old 05-20-08, 07:57 AM
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What I suspect you are feeling is driveline slack. I feel the same thing in my '01 Cherokee. I suspect you don't feel it when the vehicle is cold because the lubricants in the driveline components are also cold and more viscous. The creak you are hearing is likely a loose suspension nut/bolt.

I "cured" this surge in my '94 Grand Cherokee by replacing the spiders in my front axle. The rear axle already got new spiders as part of a Ford 8.8 upgrade. If memory serves, the spiders for the front end were like $70 for Spicer parts.

For what it's worth, the AW4s very very rarely have any problems so you can just about rule out the transmission here. A friend of mine that owns a trans shop says he has had to overhaul maybe half a dozen of them in his 18 year career. He personally owned two of them that were working just fine at 300,000 miles when he got rid of the vehicles.

- Joe
 
  #5  
Old 05-20-08, 08:42 AM
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What I suspect you are feeling is driveline slack. I feel the same thing in my '01 Cherokee.
So you haven't addressed the problem in your '01?

The creak you are hearing is likely a loose suspension nut/bolt.
I see, so the creak is a result of the surging and not necessarily related to the REASON it is surging.

I "cured" this surge in my '94 Grand Cherokee by replacing the spiders in my front axle. The rear axle already got new spiders as part of a Ford 8.8 upgrade. If memory serves, the spiders for the front end were like $70 for Spicer parts.
Is this something that can be done easily at home? Is there a way to tell if the spiders are going bad?
 
  #6  
Old 05-20-08, 08:59 AM
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Nope, I fixed it in my '94 because it was much worse (high performance trans with jacked up line pressure, and more miles). The '94 is my "project" car and the '01 is my daily driver.

You are correct. When you shift from P to D, P to R or especially from R to D the transmission shifts internally very quickly and immediately starts to accelerate - until the driveline slack is taken up. Sometimes you feel a surge/jolt, sometimes that is accompanied by a "clunk". It really all depends on how much driveline slack there is. The less slack, the less you will notice the surge/jolt/clunk.

I test for slack in the front/rear axle by seeing how far I can turn the front/rear driveshaft by hand. I could turn the front driveshaft on my '94 almost 1/8 of a turn before I felt resistance. After I replaced the spiders, the slack was almost entirely gone.

Replacing spiders isn't for the weak-hearted or inexperienced. I don't recommend anyone attempt it unless they are familiar with working on differentials. Typically, you have to pull both axleshafts and remove the carrier to remove the spiders. If the carrier bearings have a lot of miles on them as mine did, the carrier may just fall right out once you remove the bearing caps (keep track of which shims, bearing caps and bearing cups were on which side!). Otherwise, you may need to use a little force.

If you have a mechanic you trust, you can use this post as a diagnostic aid for him/her. Of course, there is no substitute for actually seeing and driving the vehicle so your mechanic will be the best judge of what is really going on.

You should be able to check all of the suspension nuts/bolts yourself though - that is relatively easy to do and may resolve the creaking entirely.

- Joe
 
  #7  
Old 05-20-08, 09:44 AM
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Replacing spiders isn't for the weak-hearted or inexperienced.
Thanks, Joe. How long can I let this problem go before I start having serious problems with the spiders? ]

I plan on at least changing the transmission fluid and filter to get it to the right levels to ease my mind until I figure out what I'll do next. I've had it less than a week, so as with any 10+ year car/jeep little problems will start to show themselves.
 
  #8  
Old 05-20-08, 10:00 AM
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If you don't mind the noise, I wouldn't bother going through the expense of having it fixed. The noise may slowly get worse with time, but I don't think this will turn into a serious problem any time soon.

I usually throw in a bottle of LubeGuard when I change the trans fluid. (sorry, don't remember which color). My friend that owns the trans shop says it is the only additive he would recommend. AW4s tend to turn trans fluid brown and I find the LubeGuard slows this process significantly.

Also, don't bother dropping the trans pan to change the filter - it is a pain in the neck and this trans just has a screen mesh filter anyway. They VERY rarely clog.

- Joe
 
  #9  
Old 05-20-08, 10:13 AM
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If you don't mind the noise, I wouldn't bother going through the expense of having it fixed.
I'll try to check the susp. nuts and bolts and as you said this may even resolve the noise.

Also, don't bother dropping the trans pan to change the filter - it is a pain in the neck and this trans just has a screen mesh filter anyway. They VERY rarely clog.

- Joe

This is good to know. From what I have heard the dipstick and tranny pan are kind of a pain to deal with anyway. I'll just go with a drain and refill approach then.

Thanks much, Joe. You have been an incredible help to this "new" old Jeep Cherokee owner.
 
  #10  
Old 05-20-08, 11:16 AM
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Not a problem, any time. We all have to start somewhere!

- Joe
 
  #11  
Old 07-06-08, 10:02 AM
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i need help with my cherekee

hi, joe sorry to bother but you seem to know alot about cherekee's, i have 1988 cherekee, 4.0L, 6 cyl, i have been having trouble starting my jeep after it has warmed up i am still getting a spark but i dont seem to be getting any fuel, i got a new fuel pump and filter also had to get a new TPS because the engine was flooding on me, i know im not getting fuel because if i spray starting fluid it starts but on a really high idle (like 3000) i found a way to lower the idle though if i unplug the 2 electrical connectors the idle returns to normal then iplug them back in and its good to drive but once i turn off the car i cant start it.
 
  #12  
Old 07-06-08, 10:09 AM
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I don't know too much about the older ones, but I'll try. Is that engine a TBI engine or a multi-port injection engine? I don't remember what year they switched to multi-port.

- Joe
 
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