ATSG has had many years dealing with great techs in shops around the world. In diagnosing problems with them, they often times share with us other problems they have struggled with and resolved. They do this because they are grateful for our help but more importantly, they like to help out others with the information. This is an example of a problem one tech has dealt with and has shared with us to be passed on to you.
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ENTER CODE : ART30 AT CHECKOUT
The input shaft and housing assembly (Figure 1) in a GM 4T65-E transmission (Figure 2) contains the Input Clutch and 3rd Clutch assemblies. The sealing rings on the housing used to contain Input Clutch and 3rd Clutch pressure seal against the inside of the Driven Sprocket Support (Figure 3). If the rings on the input shaft housing cannot seal properly inside the driven sprocket support, delayed engagements and a flare 2-3 shift will be experienced; especially so when hot.
Sal the owner of Continental Automatic Transmissions and the rebuilder Rino Partipilo do fleet work with vehicles that use the 4T65-E. Chevrolet Uplanders in fact and they are coming into their shop with as low as 20K miles having this exact same problem. By just looking at the parts you cannot see anything wrong. With the problem exhibiting itself more when hot, by the time the transmission is out and on the bench, it cools down enough where air checking the clutch circuits doesn’t reveal the problem.
Through a series of events, Rino finally came to the conclusion that the sprocket support was the problem. By running a finger across from the ring area to the bushing, it can be noticed that the bushing sits up higher than the sealing ring area on one side and near flush on the other (Figure 4). For this reason he just changed the support and nothing more and his problem was resolved. When the next vehicle came in, he did the same thing and once again, the problem was eliminated. In doing this, he also noticed that the support with this problem had part number 24219592 embossed into it (Figure 5). When he uses supports with part number 24203724 embossed on them, the problem is fixed. He did say that every now and again, like one in fifty, may give him a problem. That is with his fleet account.
He has seen the troublesome 24219592 support come into the shop in regular passenger cars having the problem but with much higher mileage. He just finished repairing a 2007 Monte Carlo and it had 80K miles. It seems fleet vehicles are coming in much sooner than with the average passenger vehicle. Either way, the nice “part” about this rebuild, you know that one part will fix two problems.