Shifting speeds question

'01 Tacoma V6 348,500 miles. At what speed level do the various shift in transmissions occur? in other words ,what speed is it at 1st when it is suppose to shift, at 2nd,etc. I understand the V6 is a 4 speed correct? I have an issue that happens right around sometimes at 55 MPH and sometimes at 65 MPH. It is intermittent as it does not always happen. No codes ever. Also when I slow down somewhere in that speed zone I feel a shudder almost like I got hit from behind just slightly. Again happens in a blue moon. Anyone experience these symptoms? I have done multiple searches and it sounds like transmission but my tranny guy says it's not?! My regular mechanic says its transmission. Wondering if this has to do with something electronic instead of mechanical? If anyone knows of a mechanic in the Orlando area that is proficient with gen 1's please post a contact.

 

I've got a MT, so not a bunch of help but @Digiratus - the "shudder almost like I got hit from behind just slightly" reminds me of the big clunk(s?) you had when we were in Colorado. Doesn't seem exactly the same, but...maybe close?

 

Carrier bearing??

 

If I had to take a wild stab in the dark I’d guess something related to the torque converter unlocking.

 

I'd say check the throttle cable (aka kickdown cable). Can stretch over time and if its not properly set, your shift points can be wonky.
This is the process -


On the subject of shift points you asked about -

 

@Area51Runner wow thank you for such a detailed answer. Thank you. So my truck should shift (with P265 70R16) from 1st to 2nd at 36-39 mph per hour then 2-3rd at 68-73 mph?

I experience these issue right around 35-40 mph and then again at 60-65 so sounds like it's my transmission that's an issue and the hit from behind is a torque shudder. I will check the cable however today. While I am at it is there a lubricant to apply to the cables?

@1997TacomaSR5 I did a full maintenance check on the carrier bearing, replace my differential oil and greased the universal joints. There isn't any play on any of those areas.

 

Nope. Do not lubricate the cable.

Although the vehicle in the video below is a Lexus, the principal is the same. This will give you an idea of how to adjust it if you haven't done this before. Of course, use the specs from the image I posted above.

Only adjust the kickdown cable for the transmission.

https://youtu.be/N_eNN_olgnA

 

No, that's only at wide open throttle, and the ECT button will change shift points

Like @0xDEADBEEF said, it sounds like the region where the TCC lockup happens, but checking the cable can't hurt