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New AW4= Weird Shift?!?

J

jrowell

NAXJA Forum User
Location
Bakersfield
I swapped an AW4 from a 94 into my 87. Everything seems to be working good, except when I shift to the 1-2 combo my jeep will not shift out of first. My old aw4 shifted normal. In the other gears (3&D) it shifts perfect.

Is the shifting different for a newer aw4? Does it shift at higher RPM's? What should I look for to fix it?

Thanks,

Jeremy
 
Actually, it sounds like your old trans didnt work right.

In the 1-2 position it will stay in 1 until very high up the rpm band, effectively if not ultimately, never shifting to 2. Then, if you ever do get it to 2, the slights reduction in throttle will cause a shift back to 1.

Use the plentiful mod threads to install a switch that will shift it into 2 and stay there.
 
The 2 AW4 tranny XJ's I owned wouldnt shift from first gear to second gear until you pretty much hit the rev limiter when you had it in the 1-2 position. See if it will shift to second a little bit above 5K RPM, don't rev to high though because I don't believe renix era XJs have a rev limiter, mine does not have one.
 
Wow, That is surprising. I thought I jacked something up.
So when you are doing a hill climb, is it just hammer down?

I'll check tonight to see if it will actually shift and I just wussed out before the RPM's got high enough.

I actually have Brett's shifter (it's not installed) I used it with my other AW4 to keep it in first! How Ironic is that!
Thanks,

Jeremy
 
You guys are right, it shifts at about 4800 RPM. I never got it that high, so I ASSumed it would not shift into second. Looks like I'll be hooking Bret's shifter back up!

Thanks for the replies, I would have been checking cables, sensors and whatever else trying to figure out why.
 
jrowell said:
I swapped an AW4 from a 94 into my 87. Everything seems to be working good, except when I shift to the 1-2 combo my jeep will not shift out of first. My old aw4 shifted normal. In the other gears (3&D) it shifts perfect.

Is the shifting different for a newer aw4? Does it shift at higher RPM's? What should I look for to fix it?

Thanks,

Jeremy
Click to expand...


If you kept the 87 TCU, the shifting should not have changed. If you swapped over the TCU, it would probably be even wierder as the TPS signals fed to the trans computer are different between those years.
 
I did not change the TCU... And the shift points definitely changed. Before I could not get it to stay in first (like when you're descending a steep hill and want to use the engine to brake)

Now It's just the opposite. It will stay in first until it seems my engine is going to take flight!

Very Bizarre!
 
Yeah, you had some kind of short the first time around. I had something similar in the past, eventually found a bare wire that fixed the situation when replaced.
 
It could very well be that the tranny itself controls the 1-2 upshift with the shifter in (1-2). In that case, there might be differences in the valve bodies between the years. Might also be affected by the position of the throttle cable as well since that controls the internal hydraulic pressure.
 
cal said:
Yeah, you had some kind of short the first time around. I had something similar in the past, eventually found a bare wire that fixed the situation when replaced.
Click to expand...

Now that you mention it, The 87's tranny wire loom was in bad shape, and there was a bare wire in it.

The New Tranny has a Brand new wire loom on it.
 
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