68RFE Fluid Level - Dodge Cummins Diesel Forum
4th Gen Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine, Transmission, etc...NO ADVERTISING

 2Likes
  • 1 Post By TransEngineer
  • 1 Post By TransEngineer
 
LinkBack Thread Tools Display Modes
post #1 of 12 (permalink) Old 10-08-2014, 01:55 PM Thread Starter
Newbie
 
Join Date: Mar 2011
Location: Calgary AB
Posts: 3
Thanks: 1
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
68RFE Fluid Level

I just changed the trans fluid and installed new filters and a BD pan. Getting the oil level correct on the 68RFE seems to be more difficult than any other transmission I’ve worked with in the past. Looking on the internet I have found charts that give exact oil level measurements from the tip of the dipstick that are proportional to the transmission temperature. I am hoping TransEngineer and any other knowledgeable members will chime in and answer a few questions I have.

1. The first set of holes on the dip stick are for a “cold” measurement 70 degrees F (21 degrees C). I live in a cold climate where it is consistently much cooler than 70 F. Therefore if I set my fluid level correct at 70 degrees it is much much lower than the two holes when I initially start the truck on a cold morning. Will this cause issues? Can the fluid level drop below the pump pickup thus starving it of oil?

2. I now have increased volume of oil due to my deeper transmission pan. I will obviously have more volumetric expansion and contraction now. Should I be aiming for the lower limit of the acceptable fill range to try and prevent an “overfill” condition when the transmission is hot and my increased volume of oil has expanded more than what was initially engineered?

3. Is the onboard transmission temperature reading accurate enough to use when adjusting the fill level.

This is my first post so hopefully I have put it in the correct place and not broken any rules….if I have please go easy on me.


2010 3500 4x4 SLT 5" TBE, Mini Maxx High Sulfer
taggs762 is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 10-09-2014, 11:36 AM
TECH SPECIALIST
 
Join Date: Feb 2010
Location: Grass Lake, MI
Posts: 3,783
Thanks: 2
Thanked 1,726 Times in 1,042 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by taggs762 View Post
I just changed the trans fluid and installed new filters and a BD pan. Getting the oil level correct on the 68RFE seems to be more difficult than any other transmission I’ve worked with in the past. Looking on the internet I have found charts that give exact oil level measurements from the tip of the dipstick that are proportional to the transmission temperature. I am hoping TransEngineer and any other knowledgeable members will chime in and answer a few questions I have.

1. The first set of holes on the dip stick are for a “cold” measurement 70 degrees F (21 degrees C). I live in a cold climate where it is consistently much cooler than 70 F. Therefore if I set my fluid level correct at 70 degrees it is much much lower than the two holes when I initially start the truck on a cold morning. Will this cause issues? Can the fluid level drop below the pump pickup thus starving it of oil?

2. I now have increased volume of oil due to my deeper transmission pan. I will obviously have more volumetric expansion and contraction now. Should I be aiming for the lower limit of the acceptable fill range to try and prevent an “overfill” condition when the transmission is hot and my increased volume of oil has expanded more than what was initially engineered?

3. Is the onboard transmission temperature reading accurate enough to use when adjusting the fill level.

This is my first post so hopefully I have put it in the correct place and not broken any rules….if I have please go easy on me.
Yes, setting the oil level on a 68RFE can be tricky, primarily because, after adding any fluid down the filler tube, you must WAIT several minutes for all the oil to run down off the inside of the tube. Otherwise, it smears on the dipstick and can give you a false "high" reading. Look at the holes in the stick to confirm for sure whether the "real" oil level is at (or above) the hole.

To answer your questions:

1. At really cold temps, the fluid may indeed be below the tip of the dipstick, however this is NOT a problem. The dipstick rests on a shelf / step on the side of the pan. The sump filter inlet is BELOW this level. You typically need to be about 4 quarts low before you start sucking air.

2. Good point! Hadn't thought about that before (I don't normally deal with deep pans). Probably not a big concern, but yes, I think it would make sense to set it near the MIN spec when cold, and then RECHECK it when hot. The hot level is what really matters. So check it once you get to normal operating temp, and if the level is OK then, it really doesn't matter whether it's at the high or low end when cold. But you're right... setting it near MIN when cold (with a deep pan) will probably make you more likely to hit the correct range once you warm it up.

3. Yes, the trans temp display in the cluster is the same number you would read with a scan tool, and it should be accurate within the sensor error (a couple degrees maybe?).

Hope that helps....
TransEngineer is offline  
The Following User Says Thank You to TransEngineer For This Useful Post:
taggs762 (10-09-2014)
post #3 of 12 (permalink) Old 10-09-2014, 11:51 AM
Cummins Nut
 
CumminsPwr89's Avatar
 
Join Date: Jun 2014
Location: Bad Newz, Virginia
Posts: 434
Thanks: 29
Thanked 51 Times in 45 Posts
iTrader Score: 2 reviews
Quote:
Originally Posted by TransEngineer View Post
Yes, setting the oil level on a 68RFE can be tricky, primarily because, after adding any fluid down the filler tube, you must WAIT several minutes for all the oil to run down off the inside of the tube. Otherwise, it smears on the dipstick and can give you a false "high" reading. Look at the holes in the stick to confirm for sure whether the "real" oil level is at (or above) the hole.

To answer your questions:

1. At really cold temps, the fluid may indeed be below the tip of the dipstick, however this is NOT a problem. The dipstick rests on a shelf / step on the side of the pan. The sump filter inlet is BELOW this level. You typically need to be about 4 quarts low before you start sucking air.

2. Good point! Hadn't thought about that before (I don't normally deal with deep pans). Probably not a big concern, but yes, I think it would make sense to set it near the MIN spec when cold, and then RECHECK it when hot. The hot level is what really matters. So check it once you get to normal operating temp, and if the level is OK then, it really doesn't matter whether it's at the high or low end when cold. But you're right... setting it near MIN when cold (with a deep pan) will probably make you more likely to hit the correct range once you warm it up.

3. Yes, the trans temp display in the cluster is the same number you would read with a scan tool, and it should be accurate within the sensor error (a couple degrees maybe?).

Hope that helps....
Good info here ^..

Thank you! I do have one question myself..

If the fluid level is above the top hole on the dipstick at operating temperature, my pan is indeed overfilled? Will this cause any major problems?

Hopefully I'am not hi-jacking this thread!

2004.5 2500 5.9 HO 24V, 99,xxx miles, S&B intake, 4" turbo back exhaust, 80hp F1 sticks, RECON LED smoked cab and tail lights, LED head light and fogs.
CumminsPwr89 is offline  
Sponsored Links
Advertisement
 
post #4 of 12 (permalink) Old 10-09-2014, 12:13 PM
TECH SPECIALIST
 
Join Date: Feb 2010
Location: Grass Lake, MI
Posts: 3,783
Thanks: 2
Thanked 1,726 Times in 1,042 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by CumminsPwr89 View Post
Good info here ^..

Thank you! I do have one question myself..

If the fluid level is above the top hole on the dipstick at operating temperature, my pan is indeed overfilled? Will this cause any major problems?

Hopefully I'am not hi-jacking this thread!
Yes, if you're above the top HOT hole at operating temp, you are overfilled, so you might want to adjust the level down. Most shops have suction guns with hoses that can suck oil out through the filler tube (or you can probably buy one at a parts store), which is a lot easier than dropping the pan and refilling.

The problem with overfilling is that if the oil gets high enough to reach the rotating parts, it will get churned up and foamy. This will cut your fuel economy (due to increased drag on the rotating parts) and it can also adversely affect trans operation, since foamy oil won't allow accurate control of clutch engagement. So check your dipstick and see if the oil has bubbles in it. If so, then you should definitely adjust it down to the correct level. Even if you have no foam in the oil, setting it at the proper level is best.
TransEngineer is offline  
post #5 of 12 (permalink) Old 10-09-2014, 12:33 PM
Cummins Nut
 
CumminsPwr89's Avatar
 
Join Date: Jun 2014
Location: Bad Newz, Virginia
Posts: 434
Thanks: 29
Thanked 51 Times in 45 Posts
iTrader Score: 2 reviews
Quote:
Originally Posted by TransEngineer View Post
Yes, if you're above the top HOT hole at operating temp, you are overfilled, so you might want to adjust the level down. Most shops have suction guns with hoses that can suck oil out through the filler tube (or you can probably buy one at a parts store), which is a lot easier than dropping the pan and refilling.

The problem with overfilling is that if the oil gets high enough to reach the rotating parts, it will get churned up and foamy. This will cut your fuel economy (due to increased drag on the rotating parts) and it can also adversely affect trans operation, since foamy oil won't allow accurate control of clutch engagement. So check your dipstick and see if the oil has bubbles in it. If so, then you should definitely adjust it down to the correct level. Even if you have no foam in the oil, setting it at the proper level is best.
Thank you! Well, I just went outside and checked the fluid level cold. The fluid level looks to be over the top two hot check holes.. This can't be good!

Happy to say, I do have an AFE deep pan with a drain plug. So, I will just loosen the plug and drain some fluid out.

2004.5 2500 5.9 HO 24V, 99,xxx miles, S&B intake, 4" turbo back exhaust, 80hp F1 sticks, RECON LED smoked cab and tail lights, LED head light and fogs.
CumminsPwr89 is offline  
post #6 of 12 (permalink) Old 10-09-2014, 12:55 PM
TECH SPECIALIST
 
Join Date: Feb 2010
Location: Grass Lake, MI
Posts: 3,783
Thanks: 2
Thanked 1,726 Times in 1,042 Posts
iTrader Score: 0 reviews
You are checking it with the engine RUNNING (in Park), correct?

Engine must be running, otherwise you'll get a way-high reading.
TransEngineer is offline  
post #7 of 12 (permalink) Old 10-09-2014, 03:19 PM Thread Starter
Newbie
 
Join Date: Mar 2011
Location: Calgary AB
Posts: 3
Thanks: 1
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by TransEngineer View Post
You are checking it with the engine RUNNING (in Park), correct?

Engine must be running, otherwise you'll get a way-high reading.
Thank You for the quick reply and the excellent knowledge you share!!!

Does it matter whether its in "Park" or "Neutral"? The Dipstick says "Neutral"?

2010 3500 4x4 SLT 5" TBE, Mini Maxx High Sulfer
taggs762 is offline  
post #8 of 12 (permalink) Old 10-09-2014, 04:14 PM
Cummins Nut
 
CumminsPwr89's Avatar
 
Join Date: Jun 2014
Location: Bad Newz, Virginia
Posts: 434
Thanks: 29
Thanked 51 Times in 45 Posts
iTrader Score: 2 reviews
Quote:
Originally Posted by taggs762 View Post
Thank You for the quick reply and the excellent knowledge you share!!!

Does it matter whether its in "Park" or "Neutral"? The Dipstick says "Neutral"?
Okay, so I made the mistake of checking the fluid level with the transmission in park. You definitely want to check the level with the transmission in neutral!!

This is how you get the most accurate reading!

2004.5 2500 5.9 HO 24V, 99,xxx miles, S&B intake, 4" turbo back exhaust, 80hp F1 sticks, RECON LED smoked cab and tail lights, LED head light and fogs.
CumminsPwr89 is offline  
The Following User Says Thank You to CumminsPwr89 For This Useful Post:
UCTJ (01-19-2015)
post #9 of 12 (permalink) Old 10-10-2014, 08:09 AM
TECH SPECIALIST
 
Join Date: Feb 2010
Location: Grass Lake, MI
Posts: 3,783
Thanks: 2
Thanked 1,726 Times in 1,042 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by CumminsPwr89 View Post
Okay, so I made the mistake of checking the fluid level with the transmission in park. You definitely want to check the level with the transmission in neutral!!

This is how you get the most accurate reading!
Actually, for the 68RFE trans, Park and Neutral are identical hydraulically, so you can check it in either position. I prefer Park for safety reasons.
lukeyn likes this.
TransEngineer is offline  
The Following 2 Users Say Thank You to TransEngineer For This Useful Post:
MBevans (10-10-2014), UCTJ (01-19-2015)
post #10 of 12 (permalink) Old 10-10-2014, 02:42 PM Thread Starter
Newbie
 
Join Date: Mar 2011
Location: Calgary AB
Posts: 3
Thanks: 1
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by TransEngineer View Post
Actually, for the 68RFE trans, Park and Neutral are identical hydraulically, so you can check it in either position. I prefer Park for safety reasons.
Good to know. Thanks!! I assume this is done to circulate and cool fluid when idling.

2010 3500 4x4 SLT 5" TBE, Mini Maxx High Sulfer
taggs762 is offline  
post #11 of 12 (permalink) Old 10-10-2014, 03:59 PM
Cummins Nut
 
CumminsPwr89's Avatar
 
Join Date: Jun 2014
Location: Bad Newz, Virginia
Posts: 434
Thanks: 29
Thanked 51 Times in 45 Posts
iTrader Score: 2 reviews
Quote:
Originally Posted by TransEngineer View Post
Actually, for the 68RFE trans, Park and Neutral are identical hydraulically, so you can check it in either position. I prefer Park for safety reasons.
Why does it say on the dipstick "check level in neutral"?

2004.5 2500 5.9 HO 24V, 99,xxx miles, S&B intake, 4" turbo back exhaust, 80hp F1 sticks, RECON LED smoked cab and tail lights, LED head light and fogs.
CumminsPwr89 is offline  
post #12 of 12 (permalink) Old 10-12-2014, 04:51 PM
TECH SPECIALIST
 
Join Date: Feb 2010
Location: Grass Lake, MI
Posts: 3,783
Thanks: 2
Thanked 1,726 Times in 1,042 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by CumminsPwr89 View Post
Why does it say on the dipstick "check level in neutral"?
Because whoever released the dipstick probably carried over the wording from the old (48RE) trans.

Or maybe you have the wrong dipstick. Does it have a part number on it?
lukeyn likes this.
TransEngineer is offline  
The Following User Says Thank You to TransEngineer For This Useful Post:
lukeyn (05-15-2017)
Sponsored Links
Advertisement
 
Closed Thread

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Dodge Cummins Diesel Forum 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 email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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 On
Pingbacks are On
Refbacks are On

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