• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

99 aw4 buzz in between P/N

4x4JeePmaNthINg

NAXJA Forum User
Location
Colorado
Got the jeep running, 99 aw4,np242

Front drive shaft in only, no tc shift linkage in yet.

I fired her up with the intention of moving her. I cycled from park to first twice, both times gave a grinding/ buzzing sound. Immediately left it running and checked fluid once at operating temp. Fluid was quite low and I added until the stick read the correct amount.

I shut it off immediately after filling because I don't know what would cause this noise.

-Does it sound like the low fluid would do this?
-Did I miss any kind of shifter cable adjustment?
-am I correct assuming the TC shifter on its housing, all the way rearward is 2wd, on click up should be 4x4 part time?
 
Yesterday I shut it down after hearing the noise. Reset kickdown and filled fluid while at operating temp. Restarted just now and cycled gears. Park to reverse is clunking not buzzing now. I have a 99 with two package so when I pulled the dash, and trans cooler I lost some fluid.
Is this from fluid getting back into the sustem?
Does trans fluid move only while driving or does idle move fluid?

Here's a link on today's noise, the t case is shifted all the way rear, whatever that is, the jeep rocks when moving through gears: Watch "Aw4 shifting, Park to reverse clunk" on YouTube
https://youtu.be/ISuEyxziVvI
 
quick update as I run out the door popped underneath and pushed the transfer case the other direction. it's now in two-wheel drive and the output for the rear is spinning, however when I cycled back up to Park before shutting it off, i got another buzzing noise in reverse? This sound is not continuous it's only once shifting into that gear like something's trying to find and then once it does it stops.
 
Last edited:
Get the whole back together. Outputs will likely spin even in neutral just from friction in trans. Sounds like tcasenis not in gear fully. Trans will move fluid at idle in park and is ok to check level that way. Torque converter was still fully seated when you installed engine? You should be able to easily spin the converter when the trans is bolted to the block.
 
If it was just free spinning the xfer case output, you'll get some grinding as you try to get it into park. No different that if you were still moving forward and tried to shift into park.
 
Get the whole back together. Outputs will likely spin even in neutral just from friction in trans. Sounds like tcasenis not in gear fully. Trans will move fluid at idle in park and is ok to check level that way. Torque converter was still fully seated when you installed engine? You should be able to easily spin the converter when the trans is bolted to the block.

I'll add the rear shaft to eliminate any free spinning outputs. I pushed the tcase lever all the way forward and confirmed rear output spinning in 2wd. I checked 3 times that the converter was seated before instal, used guide pins while mating to the trans, it went very smoothly. I did test if the converter spun freely before bolting it up to the flex plate, which it did.
 
Went on a short drive with both drive shafts installed. No clunks/ grinds while shifting or driving. Being the first time I've driven since swapping the engine I took it very easy. After driving a while and getting gas I took it home on some faster roads and tried leaning into the gas a bit more. I only tried this once, but it didn't go into overdrive.

Maybe I need to readjust the throttle cable?
 
Went on a short drive with both drive shafts installed. No clunks/ grinds while shifting or driving. Being the first time I've driven since swapping the engine I took it very easy. After driving a while and getting gas I took it home on some faster roads and tried leaning into the gas a bit more. I only tried this once, but it didn't go into overdrive.

Maybe I need to readjust the throttle cable?
I think we are getting confused on some terminology.

If you are cruising along and stomp the skinny pedal, the transmission should "kick down" (shift down) and let the engine RPMs increase, producing more power to pass. It is sometimes called "passing gear."

At least, that is what my gut tells me.
 
I think we are getting confused on some terminology.

If you are cruising along and stomp the skinny pedal, the transmission should "kick down" (shift down) and let the engine RPMs increase, producing more power to pass. It is sometimes called "passing gear."

At least, that is what my gut tells me.

Perhaps I am Mike,

It is as you say, mashing down on the gas is not causing this shifting down into the "passing gear". Like I said, this was on the way home and i only tried on one road, but I couldn't get her to switch into that passing gear.
To be clear the cable I'm talking about surge throttle valve cable, I think I said kickdown before. Otherwise nothing was changed before or after the swap, cables were simply disconnected, reconnected.
I'm scratching my head as she drove like a dream before this swap.
 
Last edited:
Shifting is controlled by the TPS via the TCU which selects electric solenoids inside the trans.

The Throttle Valve cable adjusts the internal line pressure of the trans higher for bigger throttle openings.
 
Back
Top