Mystery PO741代码

2003 F350 4X4被带到了一个transmissionshop in Eugene, Oregon. The customer complaint was an intermittent P0741 code. The code did not seem to occur when the vehicle was driven locally, but happened every time the vehicle was taken on a longer trip. The customer also noticed that the code would set whenever any additional load was placed on the vehicle. The additional loads included traveling in hilly terrain or pulling a trailer. The vehicle's transmission had been rebuilt at the same transmission shop about a year earlier and a rebuilt torque converter had been installed at that time. During the transmission rebuild procedure a few mild performance enhancing modifications were added, but other than that, it was a basic overhaul. The customer said that the lock-up worked fine for about 300 miles, but then complained that the lock-up was too soft. The soft lock-up feel continued until the present P0741 code issue. A scan check did not find any additional codes and a road test with the scanner showed that there was sufficient TCC slip to set the code. All of the routine "in vehicle" checks were performed and the cause of the problem was believed to be the converter.

在过去的一年里，传输店已经改变了手，但新老板熟悉客户并愿意由保修支持。从车辆中取出变速器和转换器。新店老板自收购商店以来，他的扭矩转换器供应商改变了他的扭矩转换器供应商乐动BBIN彩票，因此转矩转换器没有返回原始重建。转换器被送到商店的新供应商俄勒冈州换档公司。俄勒冈州转换器的生产经理Ken Cluck让转换器分开。结束游戏和离合器释放间隙在规格范围内，并且离合器看起来并不像它已经滑倒。肯确信，TCC溜滑问题始于转换器外，而是作为保险的额外衡量标准，安装了一个新的离合器活塞。

The transmission and converter were put back into the vehicle and the vehicle was road tested. The extensive road test covered all types of terrain, including several hilly areas. Since the TCC slip condition did not return during the road test, Ken felt that the problem had been resolved, even though he had not found anything conclusive inside the converter.

车辆被返回给客户，再次恢复了一下，表现良好约300英里。300 miles后，TCC应用再次开始软化。当车辆返回到传输商店时，数据流呈现足够的TCC滑动，即P0741代码的返回是不可避免的。由于转换器的反应与首次重建后的方式与其相同，因此肯内觉得他需要仔细看看。

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答案

仔细审查转换器确实揭示了第一次检查中错过的东西。I.D的衬套。TCC活塞的钻孔看起来像是新的，但窗口和涡轮机毂之间似乎似乎不仅仅是正常的间隙。当转换器是新的，该区域的OE间隙是.0015“至.002”。有一般性检查现场的单位。如果A.002“触电测量仪符合TCC活塞和涡轮机枢纽的衬套，则衬套很好。如果A.003”触角表是紧密的贴合，则衬套是边缘的，但​​将工作。如果a .004“或较大的触角表将适合，则必须更换衬套。肯发现他可以在问题转换器上安装.007”衬套和涡轮机枢纽之间的景观表（图1）。

由于没有位于活塞和涡轮机毂之间的额外O形环或车床切割密封，因此衬套和涡轮机毂之间的间隙用作孔口。由于过剩过剩，近五次油泄漏了这一区域的泄漏。肯回去检查他第一次更换的活塞。他发现，.011“触手表将适合活塞衬套和涡轮机枢纽。这种与活塞的额外间隙都可以解释p0741代码，但为什么在那里的间隙？

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答案的答案

当俄勒冈州转换器公司重建转换器时，他们重复使用涡轮机中心，这看起来像新的。涡轮机枢纽已被原始的rechuilder取代。不幸的是，涡轮机毂的表面饰面，在I.D中的衬套。在TCC活塞骑行中，足以过早地磨损套管。该区域的表面光洁度应在10至20 ra范围内。该涡轮机枢纽的表面光洁度超过了Profile仪的最大读数200 RA，并且良好的猜测将使这种涡轮机枢纽在大约300 ra下完成。完成足够粗糙以捕捉指甲，但很难在视觉上检测。事实上，O.D.问题涡轮机轮毂与OE轮毂相同，并且当您在圆周周围耗尽手指时感到光滑。如果您没有型路，请检查平滑度的最佳方法是在表面上运行指甲，或将口袋螺丝刀以45度角度放在表面上并将其推到表面上（图2）。

Most converters rely on an O-ring or lathe cut seal to control oil flow between the turbine hub and TCC piston. Because the4R100or5R110W转换器在该区域中没有任何密封，在重建过程中测量此间隙变得至关重要。

俄勒冈州转换器的生产经理特别感谢Ken Cluck，用于分享他的故事和信息。

艾德李is a Sonnax Technical Specialist who writes on issues of interest to torque converter rebuilders. Sonnax supports theTorque Converter Rebuilders Association。