47RH problems, any ideas.
#1
06-19-2012, 10:50 PM
47RH problems, any ideas.
Hey guys I'm helping a guy work on his truck, I'm not new to diesels or manual trannies but I am new to auto tranny's. The truck is a 1995 160hp 47RH truck with 351k miles. He's not hard on the truck, his granddad had it before him, but it does have some miles and wear on it. I've fixed several fuel related issues on the truck but the auto tranny is having a fit and I don't have any experience with them. The pump is still 100% stock.
When using the shifter, the transmission will go through all gears (park, reverse, neutral, drive, 2nd and 1st) without problem. Under medium acceleration the transmission will shift all the way to overdrive with only minor hesitation between gears.
The biggest problem is the transmission will get stuck in overdrive with the torque converter locked up once it shifts to it, and the only way to get it out is to manually shift down to 2nd or 1st. If you have the OD off button pressed, it will not ever shift into overdrive, but if not it will shift into OD. Once in goes into OD I don't care if you floor it in OD at 1200rpm, it won't downshift, and if you try to slow down to a stop it will kill the engine because the converter stays locked when it stays in gear, and you have to manually shift down.
Under WOT, the 1-2 shift is fine, a bit rough, but fine. On the 2-3 shift it will hang at 3000rpm until you let off the throttle and it will shift. the 3-OD shift is similar to the 1-2 shift. Another thing thats weird is that if you are driving along in 3rd gear at about 2000rpm and go WOT, it will downshift to 2nd and instantly over-rev the engine up to about 3500rpm, which it should not do.
I know its a lot of info for one post, but I want to help this guy out and figure out if its the valve body, the torque converter, the linkage, or something else. Thanks in advance guys
When using the shifter, the transmission will go through all gears (park, reverse, neutral, drive, 2nd and 1st) without problem. Under medium acceleration the transmission will shift all the way to overdrive with only minor hesitation between gears.
The biggest problem is the transmission will get stuck in overdrive with the torque converter locked up once it shifts to it, and the only way to get it out is to manually shift down to 2nd or 1st. If you have the OD off button pressed, it will not ever shift into overdrive, but if not it will shift into OD. Once in goes into OD I don't care if you floor it in OD at 1200rpm, it won't downshift, and if you try to slow down to a stop it will kill the engine because the converter stays locked when it stays in gear, and you have to manually shift down.
Under WOT, the 1-2 shift is fine, a bit rough, but fine. On the 2-3 shift it will hang at 3000rpm until you let off the throttle and it will shift. the 3-OD shift is similar to the 1-2 shift. Another thing thats weird is that if you are driving along in 3rd gear at about 2000rpm and go WOT, it will downshift to 2nd and instantly over-rev the engine up to about 3500rpm, which it should not do.
I know its a lot of info for one post, but I want to help this guy out and figure out if its the valve body, the torque converter, the linkage, or something else. Thanks in advance guys
#2
06-20-2012, 08:54 AM
hanging in third gear can be excess throttle pressure. this is adjusted by the black plastic cable coming out of the driver side of the trans. think you adjust it at the IP. the TPS may also be going. somewhere i ran across a post that really helped explain how to test it. i will see if i can find it.
Last edited by turbo2332; 06-20-2012 at 09:46 AM.
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