Replace my 42RLE or just the solenoid pack?

nondem

nondem

TJ Enthusiast
Joined
Apr 17, 2021
Messages
152
Location
Tallahassee, Fl. USA
So my transmission has solenoid issues and it's time to replace them...or replace the transmission. I'm trying to decide if I should I invest the time/money into installing an OEM Mopar($180ish) Solenoid pack and and reusable gasket etc...or just bite the bullet and get a rebuilt tranny now - hoping it's done correctly and will last.

I guess the real questions is: Do reasonably well cared-for 42RLE trannys last? This Jeep was never off road before I got it afaict let alone abused. When the solenoid isn't acting up it drives and shifts like new.

Using the carfax documented history as my guide(for what it's worth) - the transmission was rebuilt by AAMCO at 62k miles...and the fluid/filter changed at 116k miles.
The Jeep has 133k miles on it now but the fluid currently in it looks brand new. The Jeep changed hands a few times before I got it so I'm thinking everyone was trying to pass the buck after getting a dose of the random solenoid drama and it possibly got serviced again along the way.
I had it weeks before it did it because it was winter. It seems like it only happens when the transmission gets in the 'high-normal' temperature range. Getting some airflow or just letting it sit and cool off fixes it.
I got a dose yesterday w/the wife after a slow slog through some sand w/the A/C running...plus it's blazing hot here in fl.us these days.
In the long term I'm definitely adding a transmission cooler possibly a frame mounted one w/a fan. The cheapskate inside me says try the cooler first :)
Any thoughts or advice would be appreciated.
 
I'd have to get them to trigger again to see but when this first happened I believe it was 700-series codes. Basically the ones that occur when the 2-3 shift fails. I researched it at the time and it's the codes that occur when the 42RLE solenoid pack malfunctions. It eventually goes into limp-mode if you don't stop and deal w/it. It's a common enough problem that there are plenty of how2 videos on youtubez for replacing them in the various vehicles the 42RLE come in. It's not the simplest repair but it is one of the few things that can be done w/o pulling the transmission out.
While I had the transfer case out doing the SYE the hard-to-reach plug for it on the passenger side above the exhaust was accessible(barely) so I unplugged and cleaned it w/contact cleaner hoping that was the problem...it wasn't.
 
X2, the transmission code(s) that problem is generating are key to even guessing what might fix it. My 42RLE started locking up, inability to shift out of 2nd gear, and a few other things and generated a P0755 code. Replacing the solenoid pack was the most likely component that fixed it though I also installed a new transmission range selector, valve body check valve balls, and installed a Transgo Stage 1 shift kit for added insurance since I did not want to have to drop the valve body again. Here's a link to my adventure with that job... https://www.jeepforum.com/threads/f...5-code-a-bad-2-4-solenoid-indication.4304505/

Several years later it's still shifting flawlessly.
 
  • Like
Reactions: Matt131 and nondem
The P0700 is a generic transmission code that only says something's wrong with the transmission, only the P0733 means anything. It's indicating the PCM believes the input and output shaft speeds are not what they should be, could be caused by slippage.

Have you checked your ATF level or its condition? The transmission's ATF level must be checked while the engine is running and warmed up, the transmission can be in the Park or Neutral position. Make sure it's all the way up to the full mark, it's better for an automatic transmission to be slightly overfilled than slightly underfilled. If it's low make sure to only (!!!) use ATF+4 to bring it up to the full mark. Add ATF+4 via a small funnel inserted into the dipstick tube while the engine is running, checking the level as you go. It's fine/better to be a little overfilled.

Also, how's the ATF's color and does it smell burnt? The ATF should have a clear red color.
 
The current fluid is clear/new looking. I think the 733 is related to it trying to hit 3rd gear and it not being there - it just revs the engine. If I let off off the throttle and slow down 2nd gear is there again. If I keep trying it eventually throws the code because the engine is revving and the output rpm from the trans isn't matching. If I disconnect the battery it clears limp mode and as long as it sits for a bit an cools it won't do it again..sometimes for hundreds of miles till it gets into a situation that runs the temp up to high-normal. The engine temp stays normal regardless. I did check the fluid while in neutral(but cold) and it showed higher than the cool max mark. I guess I could run it around the neighborhood and make sure it is correct while hot too.
 
  • Like
Reactions: Jerry Bransford
Get a shop to read the clutch volume index of the packs (CVI). The TCM tracks the transmission wear. If your clutches are getting close to out of spec I'd do a full rebuild. The service manual specifically says color and smell of the ATF can't be used to judge condition of the fluid. I don't know why people ignore that advice.
 
  • Like
Reactions: nondem
Thanks! ...and thanks a LOT Pagrey for the tip about the CVI.
That gives me a plan of attack that reduces the chance that I'll waste the money on the solenoids.
I had decided to put the cooler on first(after rechecking the fluid hot) to see if keeping the tranny cool would make it a non-issue and failing that - do the solenoids. Now the first step will be to see if the tranny is worth putting work into.
Long term I will be putting a cooler on the transmission either way though.
 
  • Like
Reactions: pagrey
Top Bottom
Back