Ok this is a weird one. . .

[JC3006]

This is a weird one... and you guys may think I'm ignorant... But here goes. My 91 Sport 4x4 has a very odd trait. When the gear selector is in OD, the truck is very sluggish taking off from a stop. On inclines it really takes some skinny pedal to get started. If I kick the selector down to D, it feels like the transmission downshifts, and away we go. I usually just shift it to D in town, shift up to OD out on the road (works but its aggravating).

I don't think it's actually taking off in 2nd, but I can't tell for sure. It sure "feels" like it. And only in OD. For the life of me I can't figure out what is going on.

For reference, I've done the OD/Lockout converter toggle switch mod. It has fresh fluid (correct level) and filter. New adjustable Modulator and vacuum line. I've checked adjustment on the kickdown cable and the shift linkage. It has 216K miles on it, engine has been overhauled, but I'm unsure if the trans has been rebuilt (It has been in the family since 120K miles).The truck runs like new, shifts fantastic, firm but smooth. OD and lockup are great (via the switch). Reverse is a little slow to engage.

I've got everything I need for the M5OD swap, but I don't want to give up on the slushbox just yet. My only guess is the governor. But I wouldn't think shifter position would affect that. I just can't figure it out. Any ideas? Please?

 

[transman304]

OD sprag failure. Very common issue. Transmission needs to come out to be repaired.
Brad

 

[JC3006]

OD sprag failure. Very common issue. Transmission needs to come out to be repaired.
Brad

Amazing. I've fought with this for 3 months, and you solve the mystery in 45 seconds.

Will it do further damage to drive it as is, for the time being? Is it going to grenade on me if I drive it out of town? It's a shame that the trans to come out, as the it otherwise does very well (for the age). Would you do a teardown just for this issue, or would I be money ahead to go ahead with a full-on rebuild (or perhaps M5OD swap)?

Also, could this cause the infamous A4LD back and forth OD-3rd OD-3rd OD-3rd hunting? That was the whole reason I switched the lockup in the first place.

Thanks again. It's nice to finally know what the issue is.