AT Trans Slip?

My truck started doing something strange...when on the freeway under normal load, if I manually shift the transmission from 4th to 5th, the transmission sounds like it's slipping.

As it tries to change, the RPM's shoot up around 500RPM before it grabs the gear and locks in. This does not happen when I leave the transmission in 5th (or D), and it automatically shifts from 4th to 5th.

I've never dealt with a slipping AT before...when I drive otherwise, and try to put a load on, it does not slip. Anyone have this problem before? Is it just not shift properly for some reason?

Edit: The truck is also supercharged. Though this symptom did not present itself for the first few months after getting the install done.

 

Are you sure its even slipping?
When you switch any gear during driving it always try to start with 1st and than upshift to selection. maybe that is what is doing ?

 

Not really following what you're saying. But, whatever it is doing, it is not normal. I frequently change the gears manually when I'm towing or for other reasons and this is new. It also only does it from 4th to 5th. 1->2, 2->3, 3->4, all of the shifts are fast and quick to engage (i.e. normal).

 

My trucks done it since new, but its not consistent...... Had a tech ride along with techstream running and it checked out fine. Truck has had 50K miles put on it since, and approx another 120hp. Is it convertor lock/unlock?

 

When trans slipped on my old maxima, it slipped whenever I got on the gas hard with zero regard to what position the gear selector (auto) was in.

 

I have to ask the simple question first: Are you sure you're letting off the gas between the shift? If not, you could just be high-revving it while it's shifting.

 

sounds like you are just noticing the fact the torque converter unlocks to do the shift then locks back up once its fully shifted from 5th to 4th.

 

No, I'm not letting off the gas. Again, the way it's behaving is new. When shift gears 1-4, under the same conditions, it does not rev up like it does in 4-5. Its very much noticeable when it happens.

I'm not down shifting, I'm upshifting and I'm doing it manually with the gear selector. From 4th gear into 5th gear - when I push the lever over it begins to shift, then a sudden noticeable increase in rpm before coming back down and locking up.

 

Ahh, yes, I'm also SC'd...something to do with that / reprogramming of tranny shift points? This didn't happen for the first few months after install though.

 

Nope, not supercharger or mapping induced..... Happend bone stock.

 

Undo the neg terminal for thirty minutes..... Then drive and see if it shifts different.

 

4TH GEAR TO 5TH GEAR UPSHIFT . Reports at TRNI indicate the SLT solenoid has issues .
http://www.moranbahweather.com/toyota/lc_trj12/rm/rm1151e/m_05_1113.pdf
The flash also fixes the clunk upshift to 5th gear http://www.tacomaworld.com/forum/technical-chat/344879-tsb-0044-12-pinging-transmission-fix.html

https://www.tacomaworld.com/threads...th-pics-for-second-gen-4-liter-trucks.289913/

 

You are correct my friend . The re-flash is only good for 2012 and up .
Not sure what year the OP,s truck is .......its not listed .
I beleive there are a number of different clutches applied when in manual 4th in comparison to auto 4th and this may also come into play when manually upshifting into 5th

 

My truck is a 2013. Being that it's supercharged, I don't think it's an option to re-flash.

 

Overdrive or 5th gear on our trucks does not need an accumulator ( cushion ) . If I had my way , that's the first thing I would eliminate within the valve body . Remove the accumulator for 5th gear . This alone should get that laggy feeling outta the upshift . I use to do this on all overdrive transmissions and its easy to do and does not obstruct shift strategy . I am sure its done with the IPT shift kit for the supercharged transmissions

 

So, I've been looking for you guys. I have an issue where my truck seems unsure of whether or not it should go into 5th. It usually happens when I've accelerated vigourously to get to speed and then back off the throttle. The truck seems to go into 5th and then back to 4th before deciding that 5th is the right gear. It's worse if the truck is cold. I'm running the SC too. I've got about 45k on the truck.

 

I brought my truck into the dealer, they kept it for two days. They wound up telling me that it was "normal" and that they were able to re-create the condition on another Tacoma they had on the lot. I have the truck in today for 40K service, trying to have them show me this.