It says in the manual that when thr transmission fluid getts to a certain temperature it modifies the shift pattern till it cools back down
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| Funky Transmission operation after running in sand. http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=19012 |
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| Author: | GregScuba [ Mon Mar 26, 2007 10:58 pm ] |
| Post subject: | Funky Transmission operation after running in sand. |
I just got mud tires put on today, and after having them installed, I went out to a trail nearby my house. Right now The dirt here is what we call "Sugar Sand" since it hasn't rained in a while. The engine was working real hard to keep plowing through the sand, and the output speed was much slower than the input speed to the trans, or in other words, there was a lot of slipping going on in the torque converter. When I got it back on the road, I noticed it was acting real funny. The trans was holding gear and not shifting until red line, even with very light accelerator pedal input. I got home, parked it, and didn't drive it again for a few hours. Does the trans controller have some sort of adaptive programing that kicks in under conditions like I went through? Or is this a result of the heat I build up running it hard like this? After running in the fluffy sugar sand, it is aparant that this rig needs a much lower stall TC. ~2500 PRM is much to high a stall for an engine with peak torque output at 1800 RPM. Next time i think i might try running in 4-LOW in the sugar sand so that I may run with the TC locked up, and yet still be running at a safe speed. Running fast on a bumpy dirt trail right next to a deep canal is not a good idea! |
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| Author: | Joe Romas [ Tue Mar 27, 2007 7:12 am ] |
| Post subject: | |
It says in the manual that when thr transmission fluid getts to a certain temperature it modifies the shift pattern till it cools back down
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| Author: | alljeep [ Tue Mar 27, 2007 7:50 am ] |
| Post subject: | |
The problem is an 1800rpm stall speed will leave your torque converter/transmission in even more jeopardy because the line pressure being pumped by the transmission pump is rpm dependent, so lower rpm means lower pressure means more slippage. You definitely overheated it in the sugar sand - 4x4 low is the way to go. 
Wish I lived near some sugar sand/ocean/lake/ cool water feature!  Enjoy the Jeep and get some pictures up of your adventures.
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| Author: | GregScuba [ Tue Mar 27, 2007 9:11 pm ] |
| Post subject: | |
Well, I tried it again today, but this time in 4-LOW, and this time I didn't have a problem. Turned OD off so it would lock up sooner, and ran along at a comfortable speed with it in 3rd gear and the TC locked up. Went right through the sand this time with hardly a sign of bogging, and no signs of transmission overheating or anything. Thanks for the comments guys. My camera is broken, but I love to take pictures, so you can bet that once I get another camera, there will be plenty of pics. |
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