Really need help with new installed auto trans.

[zukgod]

Any help would be really appreciated. I am helping a buddy install a new/rebuilt auto trans into his 92 F250. We got it all done and no go, put it in 4wd low and it goes fine, shift out of 4wd low into 2wd and it drives until you either let off the fuel or go around a corner then it acts like it's in neutral.
Then you have to do the 4wd to 2wd again to get it to move. When she stops going the transfer case lever does not move at all it just stops. Any ideas would be great. I am lost at this point, I know the trans is good it was tested on a dyno. Thanks in advance.

 

[icanfixall]

What is the injection pump tps switch set for??? This switch is found on the drivers side of the injection pump. It needs to be set for .96 to 1.2 volts with a good digital voltmeter. Why did your friend need another trans...

 

[zukgod]

is other one cracked the housing unknown why or how. I did not check the TPS actually had never heard of it. How would one go about adjusting this? Thanks a million.

 

[OLDBULL8]

Did a search, Compliments of FOZZ.

Get a multimeter and put the red lead on the middle wire on the TPS connector (might need to slip a paperclip in there if your probes aren't sharp). Put the black lead on the neg side of the battery or a good ground. With an already warm engine (fast idle solenoid off) turn your ignition key to on (just shy of start) and keep it there. Now loosen and adjust your TPS (two torqs screws) and adjust for .92 - .94 or so at idle. Tighten the screws. Now slowly actuate the throttle and look for smooth increase in voltage, up to about 3.8 to 4 or so is normal. If the voltage jumps around or there is any dead spots, replace your TPS. Napa has them pretty cheap.

 

[zukgod]

Would this cause the transmission to act like it's in neutral?

 

[icanfixall]

Its really simple to adjust. The motor needs to be warm. Then turn on the key but don't start the motor. Make the adjustments and tighten the screws. Test by the idle setting of around .96 to 1.2 volts. Then open the throttle wide open and watch the voltage. It will go up to around 3.8 to 4.0 volts. Thats about all there is to it. The lower the idle setting is the softer the shifts will be. Low trans fluid level will make it feel like its in nuetral. These are 4 speed trans with a coast clutch. As you let off the throttle the trans "feels" like it shifts into neutral but it doesn't. As you are driving next time just touch the brakes litely and watch the tach. You are unlocking the trans and the tach gains around 200 rpm. Now let off the brake and it locks up again. Now if you let completely off the throttle the trans is coasting. All just a little throttle and the trans will lock up again and stop the coasting feeling. Maybe this is really what your feeling when you state that its going into a neutral feeling. Post back what you find out...

 

[Fozz]

No, the TPS wouldn't do that. The TPS (setting) just tells the tranny when to shift relative to accelerator input. I don't have 4x4, but your problem sounds like transfer case related or maybe double-check your transfer case/tranny shifting linkages?

 

[zukgod]

Yeah it completely kicks it out of gear, I can rev it like it's in neutral. I can't find any adjustable linkage for the t-case only the trans. I adjusted the trans linkage which was easy, but I am banging my head trying to figure this one out. Thanks for all the thought all.

 

[zukgod]

Any other ideas for the day crew?

 

[SparkandFire]

I would strongly suspect the linkage, considering how the shifter is connected mounted on the tranny, you can move it around by hand under there to make sure.

 

[Goofyexponent]

Does the T case grind when you go from "neutral" to 4 wheel drive? This is a sign the tranny is still spinning the output shaft, but the T case is not letting power through.

I would verify that the T case is actually going into gear and staying there. There should be little plastic bushings on the T case linkages. Maybe one popped off during the swap and it went un-noticed. This could be enough slop in the T case linkage to not engage in gear properly.

 

[87crewdually]

I too am suspecting t-case. I believe your going to find inside the t-case a broken range selector fork and missing bushings.

 

[zukgod]

You may be correct it might just be the T case. There were no nasties in the oil when it was pulled. But if it's a bent shift fork there would be none. If anyone else has any idea's I would love them. If not it's time to take the t case off.

 

[A_G]

same thing happened to my buddy ended up being bad connections going to the trans.
They worked fine on the old one, but when we disconnected everything the connections didnt quite contact anymore. Might check that.

 

[zukgod]

Should get to work on her this weekend. I will let you all know what happens. Thanks again for the suggestions.