Originally Posted By: Lubener
My 92 Dodge tranny (A413 with 153k) shifts great during summer months. For several years, only during the cold winter months, there is a slip during the 2-3 upshift for the first few upshifts after sitting overnight. It is fine afterwards till the next cold morning. I suspect hardened seals in the valve body. Has anyone had any success with any auto transmission additives? Band adjustments and fluid/ filter changes have not helped. I have always performed proper maintenance since day one every 40k miles.I use AFT 4 fluid.
100% the best is
ATP AT-203 Synthetic Automatic Transmission Fluid Friction Modifier
ATP
Automatic Transmission Fluid Synthetic Friction Modifier
Part #: AT-203 or AT203
10 fl. oz. / 296 mL
- Converts Dexrton III/Mercon Fluid Into a Highly friction Modified Automatic Transmission Fluid:
• Chrysler ATF Plus III & IV
• Honda Genuine
• Mitsubishi Diamond
• Nissanmatic
• Toyota Genuine
and at our Auto Repair shop in Michigan we sub contract all our transmission work to a Transmission shop and I have talked to all the Tranny techs and they have all told me
ATP is hands down the best....
They do say that lubegaurd is the most well known and does help, however its not on the same level as ATP Products.
Since you have a Chrysler / Dodge this would be the best ATP AT-203 Synthetic Automatic Transmission Fluid Friction Modifier
Its only like 20$ on ebay or Amazon,,, read the reviews on ebay or Amazon and you will see
here Ill paste a few
I USED IT WITH DEXRON III IN ZF 5HP19 TRANSMISSION AND AFTER A 300KM JOURNEY (AT HIGH SPEED) THE TRANSMISSION FLUID WAS FOUND STABLE AND WAS NOT AS HOT AS IT USED TO BE. I HAVE ANOTHER IN MY CART NOW AND AT206 M5 ALTERNATE F.M.!
Here another
shifting rumbles between 4 and 5 - put this Friction Modifier in and the problem went away immediately. Drain all the fluid you can (about 3 quarts - which you can buy on Amazon) and then put the Friction Modifier in and fill with the Honda Synthetic ATF to the right height on the dip stick. You'll be amazed.
There many more Reviews.
Here is a pic of it.