Tuckerdee

I consider automatic transmission to be full of VooDoo Magic. Some things spin in there, there's fluid that gets pumped around, and apparantly they don't last forever. I don't really know anything about them. But I need some help and advice.

I was towing a fairly weighty trailer today, maybe 10,000 pounds, pulled off the side of the road to check my load and tires, everything was fine befor this. I was headed up Turkey Creek Canyon on 285 out of Denver. When I pulled back on the highway, the transmission shifted through 1st and 2nd just fine, when it hit third, the rpms went up to the governor, I couldn't build any speed, and before I knew what was happening the transmission temp hit 250*. I wasn't thrilled obviously. Shifted down to 2nd, got up the canyon, and the tranny temp dropped pretty rapidly as well. Well I dropped the trailer, my dad's going to pick it up for me, and I got the truck home. 1st and 2nd pull just fine, 3rd and overdrive, if I build more than about 3 or 4 pounds of boost, breaks loose and just slips. So I can creep up to 65 mph slowly and hold that...just.:(

So I don't think that band is broken, but maybe an actuator piston/seal has failed and not holding pressure?

To throw a little monkey wrench in the works: last week I broke down and had to get towed because I split the transmission fluid line the runs from the back of the transmission to the fluid/water cooler on the passenger side of the engine. I lost about 6 quarts when that happened, but I have a MagHytek douple deep pan and I had a bit to spare. Did I ruin something when that happened and it's just showing up now?

So here's some of my questions:

1. Assuming I need a rebuild, do I get the cool towing transmission built? or do I just get it built back to stock? This has been a "snowmobile" every since I got it. The rpms to up to about 2200 and just stay there no matter what if you're under load and WOT. Is the $3000 transmission worth putting into a $4500 truck?

2. I did some checking a while back on DTT torque converters. The 89 was recommended to me and they went as far as to say that I would hate the 91. What do people think? I like a really solid shifting transmission. I would like it even better if there was stick coming out of the floor with some numbers and an R on it. :)

3. What else can I do to "bullet proof" this 46RH (or 47, I'm not quite sure).

I really like this truck, even though it is an auto. The engine builds wonderful power and runs very well. I've tweaked the pump a bit, added a 16 cm housing, and it works great pulling my 5th wheel. I'm just a little frustrated with the seeming transmission weaknesses, the costs, and how to fix it so I'm not repeatedly needing towed!

Oh yea, forgot to mention the truck has 243,000 miles, and, as far as I know, the original transmission.

Thanks for everyon's imput, diagnoses, and prognostications. I'll let y'all know how it goes.

edwinsmith

Time for the NV4500 swap.

Dan Brooks

Personally, I'd find a competent local shop (steer clear of the chain shops) and have a quality rebuild done. Have them add the Trans-Go TFOD-Diesel shift kit and an aftermarket torque converter (I like my Hughes, TCI makes one, and many others are available). You should be able to get that done for much less than $3000, and as long as it's properly cooled it should last another 100k miles or more.

rebal

243,000 miles gave darn good service if you ask me. im going to have a Dtt auto 4spd o/d lock up trand put into mine ,5500 buck it will be very strong for the hp output of the first gen trucks. I just cant see flopping 50k on a truck that i wont beable to work on and still not have a truck as solid as this . and as far as weekness of the tranny, its a stout unit for what it was designed for. my ex father inlaw tows a 40' fifth wheel with a scale weight of 22,450 full time rving with a 92 drw auto and the only mod done was a under bed trans cooler .and he has 260,000 miles on it (orig. trans) he keeps it serviced and ajusted on a reg basis and runs amsoil in it. I think a top quality reman is your best bet my.02
Robert

j-fox

If you plan to keep the truck, get the DTT trans. It won't be a mistake.
BTW, you burnt up the front clutch- 3 rd gear and higher.
Also is used for reverse. Does it slip?

Tuckerdee

As far as I can tell, reverse seems to work fine. But...I havn't ever given it WOT, just creeped out the driveway.

Tuckerdee

I've found the culprit. One of my old maxims, that I again failed to follow, is "check the fuse, stupid." It wasn't the fuse, but it was that the TV cable had come un-attached from the lever on the transmission. Why didn't I check that when these problems first occured? I don't know. Frustration most likely.

Again, not knowing how the internals of the automatic transmission function, what unspeakable things have I done inside the transmission? I drove the truck, with throttle, in 3rd gear maybe for 30 to 45 seconds, which was enough to heat the fluid up to about 250*. I didn't really notice any slipping in 1st or 2nd. (Read the first post in this thread for the more gorey details.) I've most likely cooked the front band? What about the clutch packs?

I was emotionally ready today to spend the big bucks on the DTT package. I talked to a nice guy, Bob, up in Greeley who is the local installer for DTT. And I think the truck would be whole different beast after a new torque converter and valve body. Now that I know what happened, I'm again unsure about what to do. Is a rebuild neccessary RIGHT now, or soon, or a little later?

Thanks again for all the imput.

j-fox

No one can answer your last question from the other side of a computer!!
Most likely you did glaze the front clutches.
If so they won't hold much.
I suggest you change the fluid and filter, and try it.
glad you found the problem.
If/when you do go to a tighter converter, you will think someone added power to it too!!
Put a rebuilt tranny on the want list.

Tuckerdee

After driving around a bit this AM the truck, to me, feels normal. Granted I'm not towing a trailer.

And after reading a bit about what the TV cable does, everything makes sense. When the cable was detached, the transmission wanted to shift very quickly up to third gear. The TV cable tells the transmission how much throttle you're using, and controls the shifts. So it thought I was using very light throttle.

As to how the TV effects third gear, I am still unsure. Does the line pressure build and hold the front band? Or does it apply pressure to the clutch packs? Or both? I'm just trying to visualize in my head what was spinning and generating the heat. A band and drum? or a clutch pack? Or both?

I'm getting the taxes done this week. So maybe I'll have enough back for new transmission and TC from DTT. Mr. Santa-Tax-Man please!

At the very least I'll change fluid and filter. Cain't hurt.