Hello all,

Recently when taking my truck out to run some errands I had a problem with the transmission shifting from 1st to 2nd. Before I noticed any problems I saw the overdrive light was on (or so I thought) while I was waiting in line at the car wash. After a few stops I was pulling up my street and noticed high rpm/ no shift into second. After the third time of letting off the pedal it shifted with a popping noise that lasted for a 30 feet or so. A few days later I looked at the truck, dropped the pan and drained torque converter. I didn't notice anything abnormal in the pan for the age of the truck, this was confirmed by a local transmission shop that I took the pan to. Changed fluid and filter hoping for a fix, test drove vehicle around the block with same symptom and popping noise. After much reading and research I took the transmission to a shop that mainly deals with diesel transmissions. I decided to tow the vehicle to him rather than risking driving it to hopefully salvage something. Before taking the vehicle to the shop it probably had 2-3 miles on the truck since the first sign of problems. I talked to the shop owner today and he test drove it and mentioned the delayed shift from 1-2 but said everything else seemed normal. Feeling better about the situation I went and drove the truck and noticed right away that this wasn't normal and there was still an issue with the shifting. At this point the transmission guy only test drove it and added fluid due to my miscalculation on the amount to put in after draining. I drove it for a few miles and had no other issues in the other gears. The only issue I had was I couldn't get into second pulling a steep grade on a side road. During this time I did hear the popping noise like three times while stuck in first but not as loud, pretty faint.

Anyways I wanted to give a brief overview of where I'm at with the truck. I now have little doubt that the problem is in the diode. I was thinking solenoid pack or something but the popping is what makes me think it's the diode or something else mechanically. The question is how far have you guys driven your trucks with the diode problem and what problems can arise from driving with a possible bad diode. The reason for the questions is my father was wanting to purchase the truck due to his needs and my need to get and different vehicle for my family needs. I have the funds to fix the transmission but we live 700 miles apart. If I were to get it rebuilt and something happens to it in his hands there's no way to warranty a transmission from one shop to another. I know there are other possibilities as far as BTS and such but that's not something we are interested I at the moment. So how far would/did you drive your truck with this issue. If I could drive it to him that would solve a lot of the problems.

3/1/01 build date on truck didn't check transmission numbers before taking to shop.
162,xxx miles, I know it's probably due for rebuild/replace hoping to change owners before handd
Thanks in advance

 

I wouldn't drive it that far. As the mechanical diode starts coming apart it will be shedding broken parts. Those parts can destroy the entire transmission.

You can warranty transmissions from one shop to another. I used to own a repair shop that had a contract with an auto parts store. If one of my customers had a problem with something I repaired and were more than 25 miles from my shop they could call a number that was on their receipt and they would be sent to the nearest shop that would honor the warranty.

CarQuest does this, as does NAPA. I'll bet several others do, too. Ask some local shops if they have that.

 

Thanks for the reply mark! I have seen your input on almost every forum/ thread I have read about the subject and appreciate your insights and knowledge on the subject. I did speak to the shop about warranty in that situation and he said it wouldn't really transfer like that. I will ask about his suppliers warranty and such. I never really thought about parts failing so much as problems with assembly which would be eaten by the shop if there were any failures.

I didn't think that driving it such distances was a good idea but figured I would ask as I recall reading guys saying they were having symilar symptoms and seemed to drive them for awhile like that, but I could be mistaken.

From what I have described does that seem to more than likely to point to the diode? I keeping hoping it is a electrical problem or problem with the solenoid but the intermittent popping is what keeps telling me it's internal. The truck hasn't towed in over a year and only driven on occasional weekends. Seems strange it happened all the sudden with no issues before.

If the diode is bad what should be replaced, the whole drum? I had one shop tell me if that was bad they would source a used one (I believe he was referring to a used sprag/ drum and not a diode)? That doesn't sound right to me.

Thanks again!

 

It's the diode.

Some people do use used parts. Often that works fine. Every transmission supply house stocks a kit to update a mechanical diode 4R100 to a sprag type one way clutch. That's the way to go. It is less expensive than replacing the drum and all the associated parts.

When I had the shop and the CarQuest warranty program it covered the entire repair, not just a part failure. If I put something together wrong and it broke they would fix it if it happened more than 25 miles from me. If it were closer I fixed it.