tranny issue
 

My 1989 W100, 318 AT runs and shifts great when cold. Once the transmission warms up, it will occasionally down shift from 3rd to 2nd. Not often but every now and then. Now after things are warmed up, it takes forever to shift into reverse from park or drive. If I let it sit for a while and cool down it will shift just fine again.

Had the same issue before and about 500 miles ago I changed the filter and fluid, not a complete flush just what was in the pan. The fluid was dark and did not have the chemical smell and there was about 2 inches of grey sludge in the pan. Looking at it I don't think it had been changed in a while. The problem went away but now it is back. So is the tranny shot? Is it rebuild time or some sort of adjustment needed? I did not adjust the bands when I changed the fluid and filter.

From what you say it seems your TRANSMISSION is done.
Now your TRANNY should be shot.
If you want to talk about your He/She in the same topic as your Transmission your not going to be taken seriously.

OK shot the tranny.
As far as the transmission, that is not the news I was hoping for. It was in the back of my mind but I was hoping not. Replacing that will cost more than I paid for the truck.

can you do the labour yourself?? I agree your transmission is probably shot, but if you can take it out and put it back in then having a shop rebuild it might be surprisingly inexpensive

Yes. A friend just had his 4L60E rebuilt. Dropped his truck off. $2500.
Thats nuts.
If you can remove it yourself your better off but they may not warranty it.

There's a shop here in lAwson missouri that my 85 2wd needed rebuilt and they quoted me 6-750 to get it dropped rebuilt and put in

is a 4l60e a 4 speed auto? anyways i agree that's crazy,

OP if you can do the work yourself another thing worth looking at is maybe summit's website I think they sell automatic transmissions for dodge's might be worth it to order one up and install it yourself, and honestly automatics aren't that hard to install

So I have come to the realization that I need a new transmission. I want to buy it myself and install it. I cannot find the stamped ID number on the transmission to know what type it is. 727, touqueflight, 46RH... I called a dodge dealer and he looked it up and said it was a 36RH? Does it have to be a specific model to work or are they interchangeable? Which transmission should I be looking for?

Easier to remove, rebuild it, reinstall.
That way you know its good.
It will cost a bit more but your knowing its beautiful is worth something.
Also, take your radiator in for a professional cleaning and flush to get all the old ATF out and any crap that could wreck your new transmission.
Including taking the lines out for a good cleaning.
With proof of cleaning you should have warranty on a rebuilt or used transmission.
I worked at a autowrecker and it is common practice to not give warranty on transmissions without proof of professional cleaning of the entire cooling system.
I sell you a transmission and it blows up.
How do I know the old sludge and grit in your cooling system didn't cause it?
With a professional shop cleaning it I know.

So it would be easier to drop it, rebuild it and reinstall it than to just put in a new one? I think it has been rebuilt once already but I cant say for sure. Is it as simple as buying the rebuild kits they sell at rockauto?