Amsoil and Mobil 1 syn. atf mix in a Jeep Cherokee

[warchildindy]

I have read about a bump, shudder, or hesitation in some automatic Jeep Cherokee transmissions. I have a 4 speed automatic in my 1999 Jeep Cherokee with the 4 liter in-line six motor.

I change the atf oil faithfully at the approximate severe use interval of 12000 miles. I have used synthetic atf (valvoline, amsoil, chrysler), since the vehicle was new.

This last oci, I used a leftover quart of amsoil universal atf and the rest was mobil synthetic for advanced mercon and dexron use. The slight bump, that I had been accustomed too, disappeared. Bear in mind, that the car has 65,000 miles.

So, for the next 12,000 miles oci, I am going to try the mbil atf by itself. I am wondering, if I finally got a good flush of all of the old oils (transmission cooler) or I finally found the atf oil, that my jeep transmission likes.

 

[buster]

I don't think you will know until you refill/flush again with all Mobil 1. Mobil 1 Gear and ATF oils are very good. Amsoil ATF is excellent also.

 

[unDummy]

If Dexron is required, the Mobil1 is an excellent choice.

Are you doing flushes, or just pan refills?

You have used synthetic since new but I've never seen Valvoline or Chrysler synthetic ATFs.

Stick with one fluid for 3-4 changes to draw a conclusion on it. Bouncing from brand to brand, from spec to spec, without full flushes, won't give you any concrete evidence on whether you created or eliminated an issue.

 

[Donald]

I have a hard time believing that Mobil 1 ATF would make a difference in shifting where Amsoil would not. Or are these all partial drains (pan refill) rather than a flush and thus hard to compare? I assume all these ATFs are spec'ed for your AT.

 

[Greaser]

The bump as you call it is a slight bind in the driveshaft splines when you come to a stop,then let you foot off the brake to move foward,you feel a slight bump.This is the driveshaft splines releasing themselves and has nothing to do with the tranny.The T case oil lubricates the driveshaft spline.This will work itself in with time and at about 85,000- 100,000 miles disappear due to the self polishing of the splines.Keep changing your T case fluid regular.Any type of Dexron IIE/Mercon fluid is fine for the AW-4,regular or synthetic.I've used Mobil 1 ATF in my 99 XJ since new for regular drain & fills and it still shifts like new at 150,000 miles.By the way the bump has been gone for a few years now.