i just put 450.00 into heater core replacement at dealer and now am getting the trans. shudder in o.d. around 1500 rpm more pronounced on slight uphill grade. i have seen several posts about this incl. transgo kit, and sonnax valves. i recently changed fluid and filter (4000 mi ago) truck has 63,000 babied miles tow small boat once year only. i installed b&m elect. trans. shift improver and rarely use it, (i guess it raises pressures in trans. to tighten shifts?). is this caused by torque converter or what? trans code "u". can someone comment??? is the transgo kit a "shift kit" and is it and sonnax valves something i can do myself. i did the last fluid change.

 

firedog,
The Transgo kit is a shift kit. It will change the way the transmission shifts. If it is just the shudder problem you want to fix, then the Sonnex valves should fix that (mine did but I also did the shift kit).
It is not hard to do the valves or the shift kit but the instructions from Sonnex alone are poor. If you know someone who has done the Transgo kit then get the tape and watch it. It will help a lot to guide you thru the removal and replacement of the valve body.

 

thanks for the reply, where can i get the sonnex valves? (tranny shop?) is sonnex a brandname? where are the valves located in the trans, can they be seen w/ the pan down? what do they do to fix the shudder? by the way your truck looks awesome!!

 

Do a search in the transmission section on Sonnex valves for about the last three months. When I got mine there was a lot of posts that explained what they do and one of my posts will give you a good place to buy them.
I got my information from others (as you are now).
Neal was the main one who clued me in and I trust his opinion.
This is a project that can be done by any Shade tree mechanic.
Have fun.

 

Firedog - I believe the correct spelling is "Sonnax", with an "a". Good luck.