Test procedure for 42RE pressures? - JeepForum.com
 15Likes
Reply
 
LinkBack Thread Tools
post #1 of 83 Old 06-16-2019, 10:05 PM Thread Starter
JaimeZX
Registered User
1995 ZJ 
 
Join Date: Sep 2014
Location: Charleston
Posts: 622
Test procedure for 42RE pressures?

Update #1 in post 10, #2 post 24, #3 post 30.

Hey guys... as I mentioned in another thread I hijacked the other day... I have a delayed 1-2 shift (~3800RPM) everything else about the tranny operation is great/normal.

Unfortunately nothing in the service manual specifically addresses the issue, but I was going to try to rent a pressure testing kit from Autozone or somebody. TV cable adjustment didn't help.

Questions:
1) Is there a way to pull tranny codes from a 1995 (non-OBDII?)
2) Is this thing what I'm looking for? https://www.amazon.com/OTC-Tools-561.../dp/B000R5G0DO
3) Can anyone say for sure if one of the included adapters fits the 42RE?
Quote:
Originally Posted by Amazon Q&A section
1/4-18 npt female quik connect plug, 1/16-27 npt male x 1/8-27npt female adap. 1/8-27 npt male x 2'' long straight adap. 3/8-18 npt male x 1/8-27 npt female adap. 1/4-18 npt x 1/8-27 npt male adap. 1/4-18 npt x1/8-27 npt female adap. 1/8-27 npt female straight adap. 1/8-27 npt male x 1/8-27 npt female elbow adap. m8 x 1.0 taper to 1/8-27 npt female adap. m10 x 1.0 taper to 1/8-27 npt female adap. m12 x 1.75 taper 1/8-27 npt female adap. 1/8-28 bspt x 1/8-27 npt female adap.
4) I assume the procedure as written in FSM is straightforward... anything weird y'all have come across? I'm not clear on what they mean by (bottom right of 21-13) "disconnect throttle and gearshift rods." Can anyone clarify?
5) What with this being the 42rE, shouldn't the TCM be commanding the shift?
5a) Over the winter, the speedometer was frequently erratic or non-functioning, although it usually rectified as the vehicle fully warmed up. It has been fine since spring. Based on page 21-5 of the FSM, I wonder if the Transmission Speed Sensor might be throwing erratic signals and causing both the speedometer issue and the shifting issue?

What am I missing?
Assuming I find a mis-match, what is the next step?

Thanks!


HID Projector retro! https://www.jeepforum.com/forum/f13/hid-projector-retrofit-build-thread-3082289/
JaimeZX is offline  
Sponsored Links
Advertisement
 
post #2 of 83 Old 06-16-2019, 11:46 PM
Timo_90xj
Web Wheeler
 
Timo_90xj's Avatar
1998 ZJ 
 
Join Date: Mar 2006
Location: Helsinki, Finland - on the European side of the Atlantic
Posts: 9,984
I can't remember the test port thread size. FSM test procedures are very straightforward.

As for shift control, RE- series transmissions use electronic control, but shift are hydraulic. Shift points are based on throttle position, line pressure, etc., TCM/ PCM controls the governor solenoid which in turn controls pressure, which determines shift points.
Check the hydraulic flow diagrams for each gear, they give a you a clue on shift pressures etc..

The reason you're measuring hydraulic pressure is because you need to know what the actual pressure is when a gear shift should occur. If the pressure is within correct range and nothing happens, you know it way better where the problem is.


Transmission speed sensor does not affect speedometer, it is more of a reference signal to let ECM/ TCM/ PCM know if you are in hi or low range and if the TSS and VSS match.


I suggest reading through the transmission section of the FSM, there is a ton of valuable info for tranny issues and how the whole system works.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
Timo_90xj is offline  
post #3 of 83 Old 06-17-2019, 05:54 AM
V8GCZJ
Registered User
 
Join Date: Sep 2018
Posts: 356
V8GCZJ is offline  
 
post #4 of 83 Old 06-17-2019, 01:36 PM
zjosh93
Registered User
1993 ZJ 
 
Join Date: Aug 2010
Location: Austin
Posts: 2,818
If I recall correctly from when I rebuilt the 42RE in my 93, all the test ports are 1/8 NPT. You should be able to buy a cheap oil pressure gauge in any parts store for $10-$15. They typically come with a 1/8 nylon hose and 1/8 NPT fittings. If you want to upgrade the hose to make it a little more robust/professional looking a flexible rubber grease gun hose usually has 1/8 NPT fittings on each end.
zjosh93 is offline  
post #5 of 83 Old 06-19-2019, 11:44 AM
paulsheer2
Registered User
1993 ZJ 
 
Join Date: Apr 2016
Posts: 1,213
Garage
BTW you may find it instructive to go to the Sonnax web site and look at all the special products they have for your transmission.

Every special sonnax part has a "this fixes xyz condition". I found it very educational.

I actually have a junktard 42RE open on the bench right now. Using my air gun to test all five ports: front/rear band actuators, front/rear clutch, OD clutch.

If all those are leak free and if you have all the sonax fix-it components, it is very unlikely your trans will have problems.

Another thing to check is oil flow: remove the rear line and run in Neutral. You should get 1 quart in ten seconds.

Valve body inspection is a good plan too. But it is tedious to dissassemble.


Sent from my SM-N910C using Tapatalk
1996maroonzjf likes this.

93 ZJ 5.2, 3.58 stroked. 242 swap. 2.5" lift. dozens of mods.
paulsheer2 is offline  
post #6 of 83 Old 06-20-2019, 04:57 PM Thread Starter
JaimeZX
Registered User
1995 ZJ 
 
Join Date: Sep 2014
Location: Charleston
Posts: 622
Very helpful! Thanks much.

HID Projector retro! https://www.jeepforum.com/forum/f13/hid-projector-retrofit-build-thread-3082289/
JaimeZX is offline  
post #7 of 83 Old 06-21-2019, 11:06 AM
paulsheer2
Registered User
1993 ZJ 
 
Join Date: Apr 2016
Posts: 1,213
Garage
See my thread "42RE shudder, no reverse"

I will post there today on updates about mine.


Sent from my SM-N910C using Tapatalk

93 ZJ 5.2, 3.58 stroked. 242 swap. 2.5" lift. dozens of mods.
paulsheer2 is offline  
post #8 of 83 Old 06-23-2019, 01:40 PM Thread Starter
JaimeZX
Registered User
1995 ZJ 
 
Join Date: Sep 2014
Location: Charleston
Posts: 622
Thanks; is your suggestion that I check for a blockage in the cooler? Or do another pan-drop/filter change to check for debris? I may well do both if nothing turns up with the pressure test. Like you, my fluid appears clean and pink. Unlike you, I haven't had any other weird issues beyond a higher-RPM shift point.

The Sonnax website didn't have anything on late/high 1-2 Shift, but their tech support helpfully suggested testing the TPS and if that reads okay, testing the governor pressure first; those'll be my first tests.

Edit: TPS seems to be reading ~4.5 at WOT, increase from closed throttle seems to be smooth, but tough to tell since my multimeter is digital. Dunno.

HID Projector retro! https://www.jeepforum.com/forum/f13/hid-projector-retrofit-build-thread-3082289/
JaimeZX is offline  
post #9 of 83 Old 06-23-2019, 03:22 PM
paulsheer2
Registered User
1993 ZJ 
 
Join Date: Apr 2016
Posts: 1,213
Garage
I dont really have any suggestions :-(

In a transmission, everything can effect evwrything else. Only a complete dissassembly and inspection of every component will give you certainty.

This video may be related to your problem:





Sent from my SM-N910C using Tapatalk

93 ZJ 5.2, 3.58 stroked. 242 swap. 2.5" lift. dozens of mods.
paulsheer2 is offline  
post #10 of 83 Old 06-24-2019, 07:59 PM Thread Starter
JaimeZX
Registered User
1995 ZJ 
 
Join Date: Sep 2014
Location: Charleston
Posts: 622
Good news! Sort of?

I now no longer have 1st gear... mostly. Pulling away from a stop takes place in 2nd gear, although there are occasional attempts at kicking down... just a boot-in-the-pants that lasts for a split second before going back to 2nd gear. Still wondering if this is electrical, since FSM suggests the following possibilities: Governor valve sticking. Governor circuit Electrical Fault. Valve Body Malfunction. Front servo piston cocked in bore. Front band linkage malfunction.

So either way, checking governor pressure will help narrow this down. Valves should be here in a few days, though the work will have to wait until after the holidays...

HID Projector retro! https://www.jeepforum.com/forum/f13/hid-projector-retrofit-build-thread-3082289/
JaimeZX is offline  
post #11 of 83 Old 06-29-2019, 07:48 PM Thread Starter
JaimeZX
Registered User
1995 ZJ 
 
Join Date: Sep 2014
Location: Charleston
Posts: 622
Update: I have now taken my transmission pressures. Some of the ports are a ^@#[email protected]# to access... ish.

Results... I SUSPECT some of the lower pressures at WOT are because the Jeep was on jack stands and not a road test? Anyway, I added my numbers to the table of "proper" values. Clearly some items are an issue. Seeking feedback. Thanks!!


HID Projector retro! https://www.jeepforum.com/forum/f13/hid-projector-retrofit-build-thread-3082289/
JaimeZX is offline  
post #12 of 83 Old 06-30-2019, 10:51 AM
paulsheer2
Registered User
1993 ZJ 
 
Join Date: Apr 2016
Posts: 1,213
Garage
This explained a lot for me:



Sent from my SM-N910C using Tapatalk

93 ZJ 5.2, 3.58 stroked. 242 swap. 2.5" lift. dozens of mods.
paulsheer2 is offline  
post #13 of 83 Old 06-30-2019, 10:57 AM
paulsheer2
Registered User
1993 ZJ 
 
Join Date: Apr 2016
Posts: 1,213
Garage
I would say the front clutch is leaking.
Needs new seals.
This explains the pattern. No?

Sent from my SM-N910C using Tapatalk

93 ZJ 5.2, 3.58 stroked. 242 swap. 2.5" lift. dozens of mods.
paulsheer2 is offline  
post #14 of 83 Old 06-30-2019, 04:09 PM Thread Starter
JaimeZX
Registered User
1995 ZJ 
 
Join Date: Sep 2014
Location: Charleston
Posts: 622
Quote:
Originally Posted by paulsheer2 View Post
I would say the front clutch is leaking.
Needs new seals.
This explains the pattern. No?
So far I have no idea. lol I watched the above video and several more... still no clue.

HID Projector retro! https://www.jeepforum.com/forum/f13/hid-projector-retrofit-build-thread-3082289/
JaimeZX is offline  
post #15 of 83 Old 06-30-2019, 04:40 PM
paulsheer2
Registered User
1993 ZJ 
 
Join Date: Apr 2016
Posts: 1,213
Garage
Quote:
Originally Posted by JaimeZX View Post
So far I have no idea. lol I watched the above video and several more... still no clue.
Look closely at the video.

Whenever the front clutch is engaged, you have low pressure.


Sent from my SM-N910C using Tapatalk

93 ZJ 5.2, 3.58 stroked. 242 swap. 2.5" lift. dozens of mods.
paulsheer2 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome