The 46RE transmissions are basically a three speed automatic, with locking converter, and an OD unit slapped on the back. The trans is acting correctly, in that the TCC disengages when you step on the brake...... as for the bog condition..... not sure it that is trans related, or, if it is a sign of a failing TPS?

 

The TPS: I've measured that to be within spec as I too, thought the same thing. But, only under loading conditions does this occur. Again, I am just starting to root this issue out.

My main goal at this point was to find out how the those two components function as to, what does what and, what controls engaging / disengaging the TC primarily.

CM

 

In fourth gear (overdrive..) with the TCC engaged (locked) the engine does tend to struggle to maintain speed/accelerate.....(especially at lower RPM's....) the PCM should see engine load going thru the roof, and either unlock the TCC, or, drop down a gear.... but, it doesn't always do that.

The Torque converter hasn't reached stall yet at 1500 RPM's or so (I don't think, not sure what the stock value is, rumors have said 1600 or so?) is it possible that simply because the engine is working so hard to accelerate in fourth gear/TCC locked, it just doesn't have the power to do so? If you lightly apply the brake, so the TCC disengages, and everything then seems fine...... That would be the direction I would be leaning. But, as it only started doing this recently..... kinda blows a hole in that theory eh?

Could also possibly be an O2 sensor on its way out? (running the engine too rich/lean might exhibit the same behavior, a perceived lack of power.) Low fuel pressure might be an issue as well.......

 

Are you sure this is controlled via the PCM? This is another answer that I am looking for- what controls the down-shift.

Now, this JUST appeared POST water pump change and, interestingly enough, I noted someone on this forum had an issue with shifting right after changing a water pump as well. I am missing the connection with that other than, the tranny lines running through the same cooling system.

CM

 

Might be product of resetting the PCM?

So far as I know...... (which really isn't very far...) everything in the trans is controlled by electronics. There are solenoids for the various shifts/TCC control. I am only assuming that the TV cable/TPS simply make changes to conditions that the PCM pays attention to, to suggest that something needs to happen, and the PCM takes it from there. Is this actually the case? Not sure.

 

Not sure- ok, it's time to find that out this weekend for sure. That is what I thought, but, that TV cable was throwing me as to why that was even there if it was done all via PCM.

I don't know squat about transmission control systems. I need more information here to go on. I see how the TCC is tied into the switch via two points on the PCM but, the thing that is throwing me is, when disengaging the TC by using the manual over-ride switch, the amount of RPM jump is huge compared to this "in between" feeling gear ratio.

Since I don't know anything about this system, I can't troubleshoot it or test it either.

CM

 

The TV cable changes the fluid pressure in the tranny, the Gov. sensor, solenoid, and the TCC and OD solenoids send this info to the PCM, along with the info sent from the TPS as to the percentage of how far open or closed it is.

 

IIRC, MonteC posted that 1-3 shifts are controlled hydraulically and TC lockup and OD are electronic, hence the difference in the 46RH and 46RE transmissions.

Clarification:

The 46RH was all hydraulically controlled 1-3 and OD. The 46RE is electronic engagement of the OD, which I believe means it does have an electronic governor OD sensor that the RH does not.

 

Total lol

Thanks for the help, Zman!!!

 

Root problem in my case was a bad MAP reading thus requiring a new sensor from the dealer this morning. All i good in the hood now.

Thanks for al the help and information on those items.

Last question: if and when the time comes: does any one have a supplier for rebulit trannies? I would like to have one on hand when this one craps out.

Thanks,

CM