I recently purchased a used transmission which worked fine when he pulled it out to convert the truck to a 5 speed. After getting it installed in my truck and getting the fluid level correct and everything adjusted properly, I think, I have no overdrive and no TCC lockup. The TCC will lock when I flip on my mystery switch but not under normal driving with the switch off. After driving the truck for approximately 20 miles I had a couple of pretty steep hills to go up on a side street in town. The trans seemed like it was slipping the entire way up both hills. While climbing a longer hill on a backroad I started up the hill and everything seemed fine and I noticed the engine temp up about 220. I flipped the switch locking the TCC and within about 300 feet with the cooling fan on the temp was back at 190. No codes showing up with key switch method or scanner.

Did you chaech the relays and fuses? Sounds like a bad converter if the electrical checks out.

Did you chaech the relays and fuses? Sounds like a bad converter if the electrical checks out.

Will double check them tomorrow. Just kinda took me by surprise when the one I took out worked fine and then this one had this problem. Any budget friendly recommended converters if I do needs one?

Will double check them tomorrow. Just kinda took me by surprise when the one I took out worked fine and then this one had this problem. Any budget friendly recommended converters if I do needs one?

Check out revmax. The stage 3 had been ender $400.

Did you chaech the relays and fuses? Sounds like a bad converter if the electrical checks out.

Rechecked fuses and relays, all ok. Would the converter be causing it to not shift into OD? I checked the fluid without it running and obviously it is overfull but there is also some black looking particles floating in the oil on the dipstick. Doesn't smell burnt or anything though. Kinda concerned about that a litte bit. I like the auto but am really starting to lean towards swapping in a manual.

Sounds like the lockup clutch in the converter died. It will not shift into OD because it has to see proper speeds and pressures which it will not attain if the Lockup clutch is slipping. I would not drive it anymore do to causing contamination damage to the rest of the tranny since there is clutch material floating through the system already. You will be needing to do a full flush including the coolers now also as that material will and probably already has plugged up the coller and or the heat exchanger which is the one on the passenger side of the block. Since you already saw high temps that could be the probles along with the lockup clutch slipping will heat things up in a real hurry.

Sounds like the lockup clutch in the converter died. It will not shift into OD because it has to see proper speeds and pressures which it will not attain if the Lockup clutch is slipping. I would not drive it anymore do to causing contamination damage to the rest of the tranny since there is clutch material floating through the system already. You will be needing to do a full flush including the coolers now also as that material will and probably already has plugged up the coller and or the heat exchanger which is the one on the passenger side of the block. Since you already saw high temps that could be the probles along with the lockup clutch slipping will heat things up in a real hurry.

Thats what I was thinking but wasn't sure since the OD is, or atleast thats what I was informed, electronic so that when I manually locked the converter clutch it should have been able to reach the speed and pressures it needed to shift into OD. I'm not trying to say you aren't right because it is obvious you know way more about these autos than I do, I'm just trying to understand. Is there anything other than ATF +4 that I should use to flush the coolers? Should I backflush the coolers or just pull the cooler return line off and do it that way?

When you lock up the converter in 3rd does it all work ok? Is it only OD with thr problem then? It could have a bad OD clutch pack too. If its just the OD that section removes easily, just remove t-case and remove rear section of tranny which is the OD section. Drive it with OD off and see if the converter locks and holds good. if it seems to hold good then shift it to OD at high speed to see if it tries to engage OD. If thats when it slips then I would say OD clutchs are bad. To flush the coolers it is best to remove them and run a solvent or diesel through them in a backwards flow from normal. Or take them to a shop that works with radiators to get them properly flushed with equipment setup to do it.

When you lock up the converter in 3rd does it all work ok? Is it only OD with thr problem then? It could have a bad OD clutch pack too. If its just the OD that section removes easily, just remove t-case and remove rear section of tranny which is the OD section. Drive it with OD off and see if the converter locks and holds good. if it seems to hold good then shift it to OD at high speed to see if it tries to engage OD. If thats when it slips then I would say OD clutchs are bad. To flush the coolers it is best to remove them and run a solvent or diesel through them in a backwards flow from normal. Or take them to a shop that works with radiators to get them properly flushed with equipment setup to do it.

Depending on road speed I do get a drop in RPM's when I lock the converter manually. The converter will NOT lock on its own regardless of speed/load etc. I had the OD turned on going 55 mph and it didn't even act like it was going to try shifting. At 55 mph I locked the TCC and the RPM dropped by 200 but still stayed in third gear. It honestly acted like a 3 speed without a lockup converter. I thought backflushing them would be best. I will have to check and see if we still have our flushing system setup at work for this kind of thing. It was put together to flush coolers and line on big fuller transmissions so i can figure out a way to adapt it to the coolers from the truck.

Not to be dumb but Have you checked to make sure the TV cable and shift linkage are adjusted correctly? Do the shift points seem to be about right or the same rpm as the old tranny? Is there a speed sensor on the tranny and if so did you swap it over from your old tranny?

Not to be dumb but Have you checked to make sure the TV cable and shift linkage are adjusted correctly? Do the shift points seem to be about right or the same rpm as the old tranny? Is there a speed sensor on the tranny and if so did you swap it over from your old tranny?

I did adjust the shift linkage and TV cable, not sure if I adjusted the TV cable correctly though. The shift points seem to be the same as the old tranny as long as it doesn't start slipping obviously. There is a speed sensor on the tranny, I never gave it a thought of that being the problem since my speedo still works correctly and reads the same as it did before. (compared to MPH reading on gps)

Adding an update and adding to the confusion a little here. I swapped out the speed and temp sensors from the trans I took out of the truck and nothing changed. I took the truck for a drive and some idiot cut me off . After the road rage took over and my truck paid the price the trans shifted into od and the converter locked up. Drove for a few more miles and stopped to put fuel in the truck. Started the truck back up and had no od or lockup again. Parked the truck that evening, drove it again 2 days later and had no od or lockup. Drove it again the third day and had od and lockup after climbing a fairly long and steep hill and the engine temp hit 220. After topping the hill the truck cooled back down to 190 (thermostat) and still everything was working fine until I stopped at a stop sign. Took off and had no od or lockup yet again. Still no codes for anything. I was hoping I would be able to rebuild the trans by now but need the truck to make the money to build the trans with so I'm kinda in a catch 22. :banghead::banghead::banghead:

I think you have an electrical issue. In this case it would be well worth a few bucks to have the dealer hook up the DRB tool and watch whats going on.

After hear about it on the phone I tend to agree with Wild & Free... There is something goofy electrically...

I tried the resistor in the wire for the trans temp sensor. Took the truck out the road and instantly noticed a difference in shifting and finally I had od and lockup again. Still feels like it slips in 3rd gear but I'll take it for now so I can make the extra money to rebuild the trans I took out of it.

Well that dumb idea worked huh? During our conversation on the phone we thought about fooling the trans temp sensor and seeing if it makes a impact on behavor. Since it did I guess the trans temp sensor is no good...

Well my dad actually called a little to late. I had already talked to you and installed the resistor when he called to tell me he finally found what he thought it was. Apparently there is a difference with the temp sensor between a 99 and a 02. I guess the 99 has the sensor transducer in the valve body and the 02 has the transducer in the dash. So as far as I can tell it was doubling the resistance and making it read much colder than the trans was. Now to just get the money together to rebuild the other trans before 3rd completely goes out of this one. I have a feeling it won't last long.

The tranny will not shift into OD until the engine gets to 140*f also IIRC.