Hard shift from 1st to 2nd under medium-hard acceleration

I have a 2006 tundra with 130k miles on the transmission. It appears the transmission was rebuilt around 90k miles. Recently, there has been a hard shift from 1st to 2nd under hard load/acceleration. All other gears shift normally and it doesn't happen when the transmission is cold. I have done a full transmission flush and filter clean. fluid seemed pretty dirty. There has not been any error codes related to the solenoids. Any help would be great as I am trying to avoid a rebuild.

 

Drain and fill is the way. Lucas makes some good trans fluid additive that can help. The harder 1-2 shift is not uncommon. My 2000 does it, that's the 4 speed auto, not the 5 speed that's in yours. It's honestly unusual for these transmissions to fail.

 

First of all, just check the fluid level (the procedure is in this video). If low, then add fluid and check it out. If you still have the problem you can perform the drain/refill procedure:
https://www.youtube.com/watch?v=ej_6BZpK3gg&ab_channel=FayeHadley
Use only WS fluid (not compatible...actual WS fluid)!

 

BG also makes a product that can be installed on any sealed transmission and I believe is guaranteed for 100k miles? And BG also warranties the transmission for a lot (or all?) of that if a licensed dealer installs the fluid, based on what the Toyota specialist shop that did my mount/balance/alignment after lifting was saying.

 

Thanks for the help! I don’t know if my shop who services the transmission fluid used ws. I know they overfilled it because I followed the procedure to check the level and about .5 quart came out. Even with the extra fluid drained I am still having a very hard slam into 2nd gear but only if I really press on the gas or am going up hill. Again it doesn’t happen if fluid is cold so maybe another flush and refill with ws will do the trick. Would I have to flush all the fluid or do a drain and fill?

 

If they overfilled by half a quart, I would actually be interested to know if they even used the correct fluid...

 

I'm reminded of this message from the last century...



I'm thinking your problem might require a specialist? Why was it rebuilt at 70k? Who rebuilt it? Did they use OEM parts? And of course, what fluid did they use?

In your shoes I would first try the drain/re-fill with WS (~4 qts - you can get Aisin brand WS fluid at Rock Auto for a reasonable price). Then I might try a complete fluid change ~ 13 qts (someone just posted that procedure in another thread, I'll try to find it in a minute). Then I would be looking for an knowledgeable, experienced, and trustworthy transmission pro (hint: it's probably NOT the dealer).

 

Complete fluid change:

https://www.tundras.com/threads/jus...-reality-and-need-advice.137134/#post-3469537

 

How hard can it be to replace a few shift solenoids?








I wouldn’t want to do it.

 

Thanks for the suggestions- I think I’ll try a full fluid flush to make sure it’s the right fluid. If that doesn’t work maybe I’ll try and figure out how to do a solenoid. Would the solenoid be acting up even if I don’t have a code? Also found the paperwork on the transmission work: