4th gear jumping (auto box)

[The Rovering Member]

There is a school of thought that says if a reasonably high mileage autobox has never had a fluid change then it's best to leave it as all the worn friction material is suspended in the fluid & compensating for the actual wear on the components it has come from. Removing it & putting fresh slippery fluid in is likely to allow the worn components to make themselves apparent. Regular fluid changes will of course reduce the wear to a minimum.

I have the same dilemma with our Chrysler Voyager. Nearly 150,000 miles & no problems with the six-speed autobox but there's a chance that the fluid
hasn't been changed.

[The Rovering Member]

There is a school of thought that says if a reasonably high mileage autobox has never had a fluid change then it's best to leave it as all the worn friction material is suspended in the fluid & compensating for the actual wear on the components it has come from. Removing it & putting fresh slippery fluid in is likely to allow the worn components to make themselves immediately apparent. Regular fluid changes will of course reduce the wear to a minimum.

I have the same dilemma with our Chrysler Voyager. Nearly 150,000 miles & no problems with the six-speed autobox as yet but there's a chance that the fluid
hasn't been changed.

[xsport]

I am not sure if the autobox is designed to do this as a normal function, program wise. If you are going down hill on the over run, i notice on my car that it will drop down a gear braking or not, but as it does this the revs do increase before dropping down . This i would imagine is to up the revs to accomodate the lower gearing. I know that there is a time delay whilst braking before this actuates in seconds , but im not sure with a manual change. Sometimes these boxes do get into a pickle program wise now and then,as they try to memorise driving style . If things seem ok now , then maybe the box has "learned "....

[goltho]

Originally Posted by xsport

I am not sure if the autobox is designed to do this as a normal function, program wise. If you are going down hill on the over run, i notice on my car that it will drop down a gear braking or not, but as it does this the revs do increase before dropping down . This i would imagine is to up the revs to accomodate the lower gearing. I know that there is a time delay whilst braking before this actuates in seconds , but im not sure with a manual change. Sometimes these boxes do get into a pickle program wise now and then,as they try to memorise driving style . If things seem ok now , then maybe the box has "learned "....

It's definitely not the retard function which activates when the vehicle's in D on overrun and the speed increases. It's a couple of seconds after I shift down from D to 4 after the lower gear engages. It's a momentary jump or slip when it lets go and then re-engages.

Dougie.

[xsport]

Have you done the fluid change yet ..

[goltho]

Originally Posted by xsport

Have you done the fluid change yet ..

Oi! Give's half a chance, Guvnor!!

("Retirement" currently is consisting of re-doing house guttering, building a large garden shed and installing an armoured supply + garden lighting, all at daughter #3's gaff. What's your excuse....?)