What is CVI. CVI is Clutch Volume Index. Brian of GotTransmissions.com said “Holy mackerel that sounds technical and complicated”. Technically speaking it is a technical marvel of modern diagnostics. As far as I know, only Chrysler TF-604 and FT 606 transmissions have this feature which makes this particular transmission diagnosis friendly.
With the correct diagnosis tool as in the Snap On Solus and Modis a qualified mechanic can extract more information about what is going on inside a TF 604 or 606 than any other transmission in the world. The handheld code readers we talked about a few months ago probably don’t have this feature. It is not like you need to use this feature every day unless you own a transmission shop..
CVI is the amount of clearance in a clutch pack. Lets see, the TF 604 has five clutch packs inside it. As mentioned in an earlier TF 604 article it does not use bands or sprag clutches. We call the clutch packs multiple clutch packs because a clutch pack may have anywhere from 3 to 9 clutches in it depending on the type of transmission.
The scan tool actually measures the amount of ATF that flows through a solenoid in order to determine the clearance based on fluid volume. The amount of information we can learn from this is staggering to say the least. Each clutch pack has a solenoid valve to allow fluid in and out of the clutch pack. That does not mean that there would be only five solenids on a TF 604. We have several other solenoids that perform other duties not related to clutch clearance.
For instance, if you have a worn out clutch pack, then in most cases the clutch plates themselves are worn, hence thinner clutch plates will produce a larger CVI due to more space in the clutch pack.
Simply put, the TF-604 is a very mechanic and scanner friendly transmission. A competent mechanic can extract more information from this particular transmission than any other I can think of with getting a headache! Enjoy GotTransmissions.com Blog, get the most out of it by getting a free subscription delivered to your mailbox every day.
