Chrysler Repair: 90 van electronic tranny in limp-in: AAMCO says code 39/rebuild?, turbine speed, free diagnostic test

Question
You have been a great help to me.  I have yet another question or two.  3.3L engine, 604 transmission. I have had this van for 4 months.  Van had sat in a garage for five years due to death of owner.  The transmission had been replaced one month prior to his passing.  Not sure if rebuilt or what though.  During cold start, the engine seems stuck in neutral after one minute.  I take the foot off accelerator and it goes into gear within a few seconds and drives fine after that.  I have noticed lately..but I think it has been doing this for sometime, just didn't realize it was wrong until yesterday, that the engine seems to be stuck in 2nd gear when driving on the highway. I brought it into AAMCO transmissions today just for a free diagnostic test.  They told me the transmission needed to be rebuilt.  Told me they got a code 39.  I am not taking their word on it. I will check around other places first.  However, I wanted to ask you for your opinion before moving forward.  Also could you tell me the cause of an engine running hot mainly on highway speeds?  I changed the coolant sensor and it seems worse than before I touched it.  Do you have any ideas on that problem?  
Thank you for any and all help you can offer me.
Tina

Answer
Hi Tina,
So all they would say is "gear ratio" codes. Well that is not very specific, I must say. It turns out that gear codes 52,53,54 mean that there is an internal mechanical problem that will likely require removing the trans from the van and opening it up. Gear codes 50 and 51 might mean that same sort of thing but there are other possibilities that are much less costly than a rebuild. And codes 56,57, 58 don't involve a costly rebuild at all. So you can see that getting the actual codes are important because all those codes are "gear ratio" codes. If you were lucky it might just be an output speed sensor that needs to be replaced ( codes 50,51 or 57) or the turbine speed sensor (50, 51 or 56). So don't agree to any "rebuild" until this is sorted out.
Roland
Hi Tina,
Did AAMCO really say the fault code was 39? That is interesting because in the Chrysler literature that I have on hand there is no indication that code number was ever used for either the transmission or the engine. If they told you 39 maybe that was there way of saying "we want you to buy a rebuild job for $2000!"
I would definitely go to an independent trans shop or even a Chrysler dealer for the trans readout and then write me back. The trans can only be readout with a special body bus plug (6 pins, 2 rows x three pins on a side) that is under the dash and the reader has to be set up to query the trans via the Chrysler data bus system. Get the true codes, what they mean, what they propose to do, and how much they intend to charge.
Given the 5 years of storage history I would be inclined to have the trans fluid drained from the trans, ask them to look for debris in the pans (a bad sign if present) change the filter and most important of all only use Chrysler brand fluid to refill. If there are serious mechanial fault codes, however, by pass this service job and write me back about what the codes are.
On the engine running hot on the highway, are the cooling fans coming on as the temp rises? One should come on at around 1/2 scale and the other at 3/4 scale. Maybe you have a problem with the fans, the relays for the fans, or most likely you have a radiator that needs to be flushed out with a strong cleaning solution because if it sat for 5 years there is a good chance that some of the tubes are partially or completely clogged. So maybe get it flushed at a radiator shop.
Roland