Engine/Transmission (1994 - 1998) Quick Up Shift & Lock Up

[JSnow]

95/Auto Cummins - Shifts into 3rd or OD (which ever is selected) very quick. After the truck starts to move forward it shifts and locks up in 15-20 yards at very low RPM/Speed. Slow enough that I have to manually downshift into 2nd and it stays in lock up when stopping. When I come to a stop I have to manually shift into 2nd or neutral to keep from killing the engine. I have disconnected my manual lock up switch and the BD PerssureLoc. I thought the TPS may be causing the trouble since I have had trouble with it in the past. A cleaning with electrical contact cleaning solution has always stopped it from falling out of lock up. I am looking for any help. I am going to take it to a shop tomorrow.



Any thoughts?



:{ Thanks for all the replies. After checking most of the suggestions, I had the pan pulled and found a bunch of ferrous and nonferrous metal in the pan. So its a rebuild :{ .



I'm convinced most of the damage came from my misuse of the manual lockup switch. I liked it so much I used it in town in place of the brakes to slow down in trafffic and for stops.

 

[98rammer]

from the sounds of it, it seems like your manual lock up is still working... .

 

[Joe G.]

It sounds like a stuck governor or VB problem. The little valve the governor operates may be worn bad, but if the symptoms came on suddenly I would not suspect it. A test on the governor port should show about 1PSI per MPH, ie. 10MPH should show 10PSI at that port. If the governor is stuck so that it has 50 PSI when you are stopped in D then the VB behaves as if the truck was going 50MPH as soon as you move. A valve could be stuck in the VB and cause the same thing. The TPS can cause problems with OD and/or TCC lockup. It should not affect the 1-2 or 2-3 shifts. Missuse of the manual lockup switch and/or the BD pressure lock could be contributing to the problem by causing damage that disconnecting them will not solve.



I have heard the that BD pressure lock can be a real problem. No personal experience with it so I'm just passing on what I have heard for whatever it's worth.

 

[Joe G.]

Another thought. If your manual lock up switch is truly disconnected, then you may have a bad lockup solenoid. You can check the electrical stuff by disconnecting the three wire connector that is above the shift lever. It connects to the VB and supplies 12 volts on the center wire, OD on one wire, and TCC lockup on the other. If you pull the plug from this connector you should not have OD or TCC lockup no matter what. Your 47RH transmission is different from the 47RE in the later trucks for this stuff.

 

[Blakers]

I had similar shifting once because my TV cable was not adjusted correctly. Just a thought before digging into anything deep.



Blake

 

[Reb.B]

i bet your detent (TV, kickdown) cable is Off. There is a ball and socket on the drivers side of the transmission, check to see if it is off. The way to adjust detent is to do it from inside the pan.

 

[Joe G.]

Reb,



This trans is a 47RH not a 47RE like you have. There is no adjustment for the detent inside the pan.



Even if the cable is off I don't think it would do that with this transmission. At the present time mine shifts the 1-2 2-3 shifts too soon. Not too bad, just a bit of an agravation that I have not had time to fix. My governor pressures are too high by about 10PSI. Mine does work just fine after it gets into 3rd so my TPS and OD lockup solenoids are working right.

 

[Blakers]

Originally posted by Reb. B

i bet your detent (TV, kickdown) cable is Off. There is a ball and socket on the drivers side of the transmission, check to see if it is off.

If the TV cable is off (or broken inside the sheith), line pressures would be too low, not too high. But a too tightly adjusted TV cable would make the line pressure too high.



Blake