towing help with a 4L80E

[Chuck1]

I have an 1994 6.5TD with a4L80E transmition and i tow a 25' 5 wheel .When climbing mountains I think the tranny is slipping .climbing the RPM's stay the same but the speed drops like a rock.Is there any thing I can do to slow the slipping

[HowieE]

The convertor in the 4L80 will lock at about 50mph and light throttle. It will unlock if the road speed drops below 50 or if the throttle pressure is inceased much like a "kickdown".
If you are traveling in excess of 50mph when this happens it is most likely a reaction to you throttle pressure as you climb the hill and is normal with added the load of the trailer.
Traveling with a smaller trailer on level ground at speeds below the locking point the convertor will be unlocked but the tack may apear to show a constant relationship betwen itself and the speedometer, This is not a locked condition but rather the convertor is able to transmit the required power without showing any slippage.
To cure the excess towing unlocking you can install a locking devise. BD has one that allows you to lock the convertor at any speed above 33mph rather than the 50+ that GM built into the trans. Locking the convertor while towing will greatly reduce heat.
Others that have seen my posts will question why I would recomend BD since I have had years of problems with mine, but the differance is the BD TorqueLoc will work on the older pre 97 computers.
So good lock.

[Chuck1]

Howie how hard is it to install the BD lock up and how much do they cost

[rjschoolcraft]

The article in this link (http://www.thedieselpage.com/reviews/torqloc.htm) should help with the installation question. Check BD's website for current pricing.

[HowieE]

Installation is not hard but I would change one thing during the instalation. My price is 4 years old so check the web.
The Brown wire ,TCC PVM solinoid, can be accessed at the PCM in and under the glovecompartment. It is on connector C3 at location c5. I chose to connect here to reduce problems that come with connections made under the truck and in the weather.
You will have a plastic planel just to the right of your instrument panel that can be popped out. This makes a good spot to mount the switch. You will also find switched DC on a connector, not used, that you may need for the switch lamp.