Torque converter not engaging?

[Mogman]

According to the schematics I have 97A/B are the wires that used to go to the RPM sensor on the back of the engine to the diag. port.
There would be no sensor like that on the turbo motor because there is no place to install it with the turbo, that sensor was only used for diag. and has no bearing on the transmission.

 

[Mogman]

#349 and 359 are the ESS, 359 is ground for some of the sensors so it is connected to several sensors.

 

[Mogman]

Are you sure the transmission is not locking up at the same time it shifts into 4th?
If you are driving along in 4th hold the throttle for a steady speed and touch the brakes, if the TCC is locked up you should be able to detect the difference as when you touch the brakes the TCC should unlock.
Any of the issues that would keep the TCC from locking up SHOULD set a code, although it does take several (7) starts/runs/stops to set a code if the brake switch is at fault.

 

[Gcelevator]

#349 and 359 are the ESS, 359 is ground for some of the sensors so it is connected to several sensors.
View attachment 917137

Yes, you are correct in both of your statements. I am trying to find cables 497 and 498, i see them coming out of one of the selenoids in the transmission but i can't find them in the front. I will keep checking into this, but is dark now. I will study the schematics and target this next. Thanks.

 

[Gcelevator]

Are you sure the transmission is not locking up at the same time it shifts into 4th?
If you are driving along in 4th hold the throttle for a steady speed and touch the brakes, if the TCC is locked up you should be able to detect the difference as when you touch the brakes the TCC should unlock.
Any of the issues that would keep the TCC from locking up SHOULD set a code, although it does take several (7) starts/runs/stops to set a code if the brake switch is at fault.
View attachment 917138

It could be, not today but i remember i tried once and while at probably 60 MPH i touched the brakes and i hear an increase in RPM or something unlocking. This is the thing, i am good with diesel but transmissions are new to me, my background is marine diesel.
But now i am concerned, i can not fined wires 497 and 498 in the front.
Probably i am trying to fix an issue i never had.

 

[Gcelevator]

Are you sure the transmission is not locking up at the same time it shifts into 4th?
If you are driving along in 4th hold the throttle for a steady speed and touch the brakes, if the TCC is locked up you should be able to detect the difference as when you touch the brakes the TCC should unlock.
Any of the issues that would keep the TCC from locking up SHOULD set a code, although it does take several (7) starts/runs/stops to set a code if the brake switch is at fault.
View attachment 917138

Problem that never existed solved, it is engaging at the same time the 4th gear engages i assume. Went for a test drive, touch the brake and voilà. Engaged and disengage.
Thanks mog.

 

[Gcelevator]

Are you sure the transmission is not locking up at the same time it shifts into 4th?
If you are driving along in 4th hold the throttle for a steady speed and touch the brakes, if the TCC is locked up you should be able to detect the difference as when you touch the brakes the TCC should unlock.
Any of the issues that would keep the TCC from locking up SHOULD set a code, although it does take several (7) starts/runs/stops to set a code if the brake switch is at fault.
View attachment 917138

Sooooo, the next questions should be: can the shift points be changed in this truck? Is that easy to do? Reason i am asking is, this was an armored truck and probably due to weight the shift pointas are kind of high. For instance, 4th gear engages between 47-50 miles. Is that normal in this type of trucks?

 

[Mogman]

Sooooo, the next questions should be: can the shift points be changed in this truck? Is that easy to do? Reason i am asking is, this was an armored truck and probably due to weight the shift pointas are kind of high. For instance, 4th gear engages between 47-50 miles. Is that normal in this type of trucks?

You can change the PROM, other than that you cannot "program" the shift points.
Again this depends on if you have an original style or purchase an original style TCM, the PCS TCM is not programmable AFAIK.
It is said the NA has lower shift points, the PROMS are relatively cheap from Eastern Surplus.
https://www.easternsurplus.net/Products/SearchResults
You can also "fudge" the TPS (to a point) to think you are not into the throttle as much as you actually are to get it to shift earlier.
EDIT, if you can get into the TCM you can search the part number on the PROM (under the small cover) and see what you have.

 

[Mogman]

The PCS TCM comes in basically two versions also, I think there are actually 4 different part numbers, 2 for NA and 2 for turbo.

 

[Gcelevator]

You can change the PROM, other than that you cannot "program" the shift points.
Again this depends on if you have an original style or purchase and original style TCM the PCS TCM is not programmable AFAIK.
It is said the NA has lower shift points, the PROMS are relatively cheap from Eastern Surplus.
https://www.easternsurplus.net/Products/SearchResults
You can also "fudge" the TPS (to a point) to think you are not into the throttle as much as you actually are to get it to shift earlier.
EDIT, if you can get into the TCM you can search the part number on the PROM (under the small cover) and see what you have.

Ok, probably that explains my assumptions. The engine is a turbo with the TPS originally from that engine. Usually when the pump is sent for repairs/tune up the TPS are not moved. It could be this TPS was always adjusted (as should be) for the original truck (unknown where it came from) and probably that is why the shit points are higher now paired to a transmission that was originallyfor a NA. If that makes any sense.

 

[Gcelevator]

The PCS comes in basically two versions also, I think there are actually 4 different part numbers, 2 for NA and 2 for turbo.

I have 2 or 3 more PCS's from other trucks i have, one of them being a donnor. I might try down the road replacing it. I will try 1st to remove the cover of the one being used and figure out what model as you suggested.