I have a problem with my truck hunting for OD. You can be @ 50+ mph and it will kick into OD for a second... out for a second... in for a second... out for a second. Usually no longer than in for a second.... and out as long as 5 minutes.


The troubleshooting I have done:

Let truck idle in gear to let the fluid get warm (160) No change

Fluids are full and fresh.

Tried to use a 1K ohm resistor like the second gen trucks use to bypass the factory tranny temp. No OD whatsoever.

The only other thing I can think of is the TPS. BUT.... the OD doesn't kick in at speed (50+ even if I floor it or let completely off... or anywhere inbetween for that matter)


Anyone of you all have a starting point for me?


This is a 93 4x4 BTW.


Thanks for the help.

 

Are you saying that the truck doesn't ever go in to overdrive, or sometimes it hesitates? I had a problem with my truck kicking in and out of OD only going up hills, and when I installed my DennyT fuel pin, it got rid of the problem completely. I know that won't help, but I just thought I would share...

Is your truck stock? I would check over the tranny lines, and make sure everything is nice and tight, and no corrosion has done any damage. Sorry I can't help much, I'm new to the tranny world...

Parker

 

My 93' W250 had the same issue. I ended up messing with the speedometer gear reducer adapter (located on the T-case). This pesky little rascal caused all my OD problems. I tested everything, cleaned connectors, and even bought a new one. The problem was fixed, at least for 400 miles............then it returned. I permantly fixed the issue by omiting the gear reducer adapter. This caused my OD to work, downside was that my speedometer is 10 mph off and OD comes on late. I still need to go back and find out what is going on and fix it right.

 

I had the same experience. We finally deleted the speedo gear reducer and all is fixed. I now use a GPS to keep track of speed.

 

i vote for the TPS, my truck did the same thing.

 

Check your ground wires, start at the battery then check/clean chassis grounds, dirty or loose grounds will cause this problem. Good luck.

 

Same here, my truck did the same thing Adjusted the TPS and all was well.

 

Check the kickdown spring and make sure its not missing or broken, and that its not a weenie spring. See this thread for my fun with OD and what to do if your spring is broken or gone. It was the cause of my problems. And the TPS is another common one.

 

Mine was the TPS...It would go into O/D when i would give her fuel, then out as soon as i let off. I hooked up a Potentiometer last week and it works like a charm. (Fixed my cruise controll issue as well)

 

I vote for the tps, throttle position sensor... I have a 93 with 204000 miles on it and have put 3 on it... It goes and comes....somtimes I was able to peck on it with my knife or screwdriver and it would work for awhile..