Does anyone know if the th350 has various input shaft lengths. I'm told that there is a couple of different lengths. I thought the th350 had just one input shaft length. o No: I'm told the difference is at the end where the shaft tapers. I'm having converter clearance issues. Any help would be great. Jim
I believe you are thinking of tailshaft differences. The input shaft lengths should be the same. What kind of converter issues are you having?
Hi Larry, no it's the input shaft I'm talking about here. I'm not getting the required depth I need in the measurement from the foot pad on the converter and the bellhousing. Should have a least 15/16 to 1" clearance and I'm only getting 3/4". The company that I purchaced the converter from (not going to mention) is telling me I have the long input shaft in my th350, the end of the shaft has a taper that is approx. 3/16" longer than the shorter 350 shaft. All of this is news to me. He went on to explain to me that this is the difference that I need for the converter to sit deeper in the pilot, thus getting the clearance that I need. I'm beginning to question his theory though, as two reputable trans shops here have never heard of this and looked at me like I was on crack :laugh:
Jim, According to my Ron sessions book on the THM 350, the only difference I see is the input shaft for 1977, and up non-TCC mdels used a different seal where it pilots into the output shaft. Other than that, no difference. You aren't seating the converter completely. Sometimes that can be a real problem. The converter will click into place 3 times as you engage each set of splines. You just have to keep on turning and pushing in until it seats. Did you pour a quart of ATF into the converter? If you can't get the converter to seat, there may be a problem with the converter splines.
Larry, that's what I thought at first, that I wasn't getting the converter seated all the way. But I was, cause I even took the tranny and converter to my transmission guy just to make sure I had it engaged all the way. You can even see when you look inside the converter that the input shaft is making contact with the pilot hub. I'll be suprised if there really is only one length of input shaft for the th350. As this is a very reputable company that sold me the converter. For them to lie about this sort of issue is VERY poor customer service and jeopardises there reputation. I am beginning to wonder though, as I was shown no less than 15 th350 input shafts from two transmission shops, and every one was the same as mine.
Was the trans recently rebuilt? If so, there can be issues if the pump driver gear was installed incorrectly. This is the gear that the converter hub locks into as the 3rd click. Installing it upside down means the tangs will engage the hub before the converter is fully seated and will give you less flywheel clearance. When the gear is installed in the pump, the tangs are supposed to be "up". It means they are down at the front of the trans and lower allowing the converter to go further into the trans. The only longer input shaft if for the 81 and later TH350's which have the lock-up converter. This should not be an issue in your applicaton. Mark
Mark, this trans was recently rebuilt. If this pump gear was installed wrong, what sort of clearance issues does that create? Also will this damage the transmission? Thanks I think, :laugh: Jim
To the best of my knowledge it will damage the trans if installed wrong. The main reason would be that the converter would be pushing the gear into the back half of the pump (called the cover). This would cause binding, wear and loss of pump pressure. Other issues with the converter could result as well. Here is my suggestion to avoid having to take the trans apart unnecessarily. Try to measure the distance from one of the tangs to a stationary surface of the pump (the white gauge you get in a carb rebuild kit works nicely). The front seal surface may do. Then find another TH350 that you can compare the distance to. My guess is that you will have about 1/4" difference between the two if installed wrong. If so, the pump will need to be remove and the gear reversed. I don't have a TH350 pump handy to get the measurement for you at the moment. Plenty of TH400 ones, but you really want to compare like to like. If you are unsure about any of this, the safest bet is to remove the pump and check for sure. Hope this gives you an idea. Good Luck, Mark
