47re Problems

jorg221

jorg221

New member
Joined
Oct 16, 2010
Messages
20
Well guys, i got a bone stock 99 with a 47re that just started acting up today. Truck has 82,000 miles on it and i havent had any problems it till this morning. On my way into work the trans shifted just as it always has for about the first 7-8 miles. Driving about 50mph in OD, all of a sudden it downshifted, then picked overdrive right back up, and was fine for about the next mile. Turned onto a different road and things took a turn for the worse. As soon as i turned and rolled back into the throttle, the truck would rev to 3000 with no hint of shifting and was stuck in 2nd gear. Any throttle input over about 30%, and the truck would just rev. I had to limp it a couple miles and it never shifted out of 2nd.

I was talking to a guy at work who said one of our old shop trucks did the same thing. He said there is a temperature sensor in the valve body, and if it goes bad, the transmission will go into a protection mode. He said if hooked to a scanner, temperature would read super high. Apparently the only way to fix this sensor is a new valve body.

Anyone have any input on what could possibly be wrong, or some things i could check at home to try and trace down the cause? I am by no means a transmission expert, but any andvice/input would be greatly appreciated.
 
Just need a new pressure sensor if it is a temperature issue.

When a trans goes to limp mode, it goes to 3rd gear. So picture how your truck ran before in 3rd gear.

Also if it is electrical you should be able to go strait to manual 1 and then manually shift the gears. You won't get lockup or OD. You will only get manual 1, if you go directly to neutral, and only get it one time for every time you hit neutral.
 
I manually shifted it to 2nd and it made no difference, i didnt let the truck downshift any further, just in case it woudlnt up shift and i couldnt limp it to work. It seemed to me that it was in 2nd, 12-15 mph was all i could get out of it at 1800-2000 rpm. Im not sure if it is a temperature issue or not. Fluid is nice and red, doesnt smell burnt and the level wasnt low. I loaded the truck on a trailer and hauled it home and havent driven it since, wanted to get some input before i went any further. I will try to manually shift it tommorow, is there any way to manually shift it from 2nd to 3rd then 3rd to 4th, just seems that you can only manually shift 1-2 then 2- drive.
 
You can manually shift it to D which will be third. Is the truck bone stock?
 
Whats all involved in getting to the pressure sensor, and is there a way to test it? Im not a transmission guy by any means, but am familier with a wrench.
 
If you get a good scanner it will read the temp. However if your in 2nd gear your probably not in limp. When the 47RE/48RE goes to limp it is direct(3rd), and you lose OD and lockup.

There is a power transmission relay that you could jumper if you think it is going to limp.

First place to start is see if it will run through the gears manually.
 
Thanks Dan. It will have to wait untill tommorow untill i can take it out and see if i can shift it manually. I will update this after i run it.
 
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