Help! No 4th gear in my HD!

[929_owner]

Hey all, I have a 1994 HD with 95k miles on it. The day I bought it I brought it home 100 miles and all was well. The next day, it refused to go into 4th gear completely. It went through first through third perfectly, but no fourth regardless of speed. I noticed though that if I was at a 4th gear speed, if I took my foot off the gas it would shift into neutral and as soon as I reapply gas it goes right back to 3rd!

Anyway, long story later, after having a friend blow the motor after letting him borrow it, I replaced the motor and trans together from a junkyard car with 160k. Found personal info from the owner of that car and was told it was mechanically sound. Got junked for because the valve cover gasket leaked and it needed a ball joint (women... seriously..?)

So with the alternate transmission again, it has the EXACT same symptoms. Does 1st through 3rd PERFECTLY smooth. I mean seamless, but still no 4th, and still goes into neutral when you coast, otherwise it's back to 3rd again.

When it's cold, the transmission usually doesn't engage 4th until ATF temps rise a bit more, and I notice that it doesn't go into "fourth" or neutral like it does until it warms up properly, if that indicates anything.. atf temp sensor works?

No hold light, new atf fluid when I put it in and I've replaced the TCU already to no avail. Not sure where else to look now.. Please help! This is becoming a nightmare and I'm a broke student! This thing is robbing me of gas and time trying to figure it out! Thanks!

[DMiester129]

hold light on?

[929_owner]

Originally Posted by DMiester129

hold light on?

No hold light.

[DMiester129]

something in the valve body or your tranny ecu

[Matsuda 9]

can you turn hold on and the light goes on? blown globe could give you trouble trying to diagnose your issue.

for the rest have a look here:
Mazda929.org • View topic - HD Manuals

[929_owner]

Originally Posted by Matsuda 9

can you turn hold on and the light goes on? blown globe could give you trouble trying to diagnose your issue.

for the rest have a look here:
Mazda929.org • View topic - HD Manuals

Yes, the hold button does work properly and function. A blown globe? What do you mean?

Also, I do have that manual and have looked through it. There wasn't anything I could find to help me diagnose it. There weren't any tcu codes either. I can't really find much that would inhibit shifting to 4th gear. And there aren't many sensors on the transmission anyway. A speed sensor, pulse generator, inhibitor switch, dropping resister, and the solenoids. Not sure where to begin!

I mean, what would cause it to go into neutral as soon as I left off the gas? I think it's unlikely its something internal, especially since BOTH transmissions in the car do the exact same thing.

[Matsuda 9]

i thought that manual covered the Tranny codes...

anyway, globe i was talking about the hold light, if its lighting up then its a good start.

for codes, head here then:
MPVClub.com :: Do-It-Yourself Articles

you will be amaized how things can die in the same way... been there done that.... mine used to slip out of the 4th as soon as i would put foot down... 3 gearboxes later same problem, 4th was good

[older929]

Transmission inhibitor switch. Broken or needing adjustment. On the side of the tranny where the gear shift connects. This is a maybe but I had a bad switch once and the tranny worked weird.