| LOST JEEPS http://www.lostjeeps.com/forum/phpBB3/ |
|
| Transmission Issues - Volume Index Low in Valve Body issues http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=3&t=42988 |
Page 1 of 1 |
| Author: | Stream [ Fri May 08, 2009 4:23 am ] |
| Post subject: | Transmission Issues - Volume Index Low in Valve Body issues |
Hi all, I have started to notice that on take off the vehicle felts like it does not engage gear properly (2003 3.7lt), almost like the transmission is slipping! So thought a flush and new transmission fluid would fix the problem, so down to the dealership it went. Turns out that I have a 'Volume Index Low in Valve Body' issue, anyone come across this? It seems like I am the first as unable to find any threads on the subject. I have booked it into a transmission shop to find out what the problem might be. Any thoughts, advise or experience with this issue would be appreciated. I really hope it is not going to be a huge problem???? |
|
| Author: | Jeepjeepster [ Fri May 08, 2009 9:26 am ] |
| Post subject: | |
Are you talking about a slow engaging when you shift from P to D or R to D, etc? |
|
| Author: | tjkoen01 [ Fri May 08, 2009 1:09 pm ] |
| Post subject: | |
from the service manual...this is for the 45RFE: Clutch Volume Indexes (CVI) "An important function of the TCM is to monitor Clutch Volume Indexes (CVI). CVIs represent the volume of fluid needed to compress a clutch pack. The TCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input, or Turbine Speed Sensor sends an electrical signal to the TCM that represents input shaft rpm. The Out-put Speed Sensor provides the TCM with output shaft speed information. By comparing the two inputs, the TCM can determine transmission gear position. This is important to the CVI calculation because the TCM determines CVIs by monitoring how long it takes for a gear change to occur (Fig. 13). Gear ratios can be determined by using the DRB Scan Tool and reading the Input/Output Speed Sensor values in the "Monitors" display. Gear ratio can be obtained by dividing the Input Speed Sensor value by the Output Speed Sensor value. For example, if the input shaft is rotating at 1000 rpm and the output shaft is rotating at 500 rpm , then the TCM can determine that the gear ratio is 2:1.In direct drive (3rd gear), the gear ratio changes to 1:1.The gear ratio changes as clutches are applied and released. By monitoring the length of time it takes for the gear ratio to change following a shift request, the TCM can determine the volume of fluid used to apply or release a friction element. The volume of transmission fluid needed to apply the friction elements are continuously updated for adaptive controls. As friction material wears, the volume of fluid need to apply the element increases. Certain mechanical problems within the input clutch assembly (broken return springs, out of position snap rings, excessive clutch pack clearance, improper assembly, etc.) can cause inadequate or out- of-range element volumes. Also, defective Input/Output Speed Sensors and wiring can cause these conditions." A low index value would explain why you get the feeling like the transmission is slipping....because it probably is...low index value = less fluid to engage a clutch. The question is what made the index number so low. There are only 3 inputs to the TCM to make that calculation. It could be one of those sensors, if it's not one of them, they you have a mechanical problem. Let us know what you find out. |
|
| Author: | Stream [ Sat May 09, 2009 6:52 am ] |
| Post subject: | |
Thanks for the information, sounds like my problem. Shall keep you well informed. |
|
| Page 1 of 1 | All times are UTC - 5 hours [ DST ] |
| Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |
|