What is normal trans operation like?

[partsguy84823]

Hello, forgive me for such a generic question, but this is my first 4R100, my first 7.3, and my first truck with an auto. So, I have some questions.

First, what speed will this transmission shift into OD? It seems like mine flat out won't do it under 45mph. If I'm cruising around that speed, it will act like it 'wants' to but it won't actually kick up untill I pass 45mph.

Also, in what gears will the TC lock? It seems like sometimes it like to coast, and other times it will be locked and I can't quite figure it out. I'm so used to driving a standard transmission that this TC lock/unlock thing is weird to me. Its especially weird to be coasting at 30 mph with the engine idleing and then go to get back on it and watch/hear the rpms have to 'catch back up' to the driveline.

One last thing, how accurate is the trans temp indicator on the factory dash. I understand that its nowhere near as acurate as an aftermarket gauge (i mean it doesnt even have numbers) but in general if it never excedes half way up on the scale, am I still safe?

Are there any major signs or clues that this transmission might be failing, or anything to watch out for that would be a sign? The fluid is a good color and smells like good clean trans fluid.

[symbols]

The factory designed the trans to slip into OD so the TC lockup is not harsh so that is normal. I think it starts to engage at 45 and locks at 55 or something like that. You can buy a module to fix it and/or programming will fix some of it. I have mine for sale if your interested

I've never seen a factory trans gauge in 7.3 so I don't know what your seeing there. Either way its a dummy light and not accurate in any way.

[Cutty72]

I'm in the same boat as the OP, so subscribing.

Also wondering, my pickup has 100k on it and I don't know the prior maintenance records. Should I flush the tranny, change the filter, add an external filter, etc. What's the recomendation?

[partsguy84823]

Originally Posted by symbols

The factory designed the trans to slip into OD so the TC lockup is not harsh so that is normal. I think it starts to engage at 45 and locks at 55 or something like that. You can buy a module to fix it and/or programming will fix some of it. I have mine for sale if your interested

I've never seen a factory trans gauge in 7.3 so I don't know what your seeing there. Either way its a dummy light and not accurate in any way.

Thanks for the response. The 02/03 7.3s got the updated gauge cluster, which includes a trans temp gauge in the upper right corner of the dash (where the volt-meater is on a standard trans truck). It does appear to be a variable gauge. It moves depending on how hard I'm being on it, but I don't trust its accuracy very much.

Here is a picture of the newer 7.3 cluster I found online...

[aawlberninF350]

The stock tranny gauge is simply an idiot light, absolutely useless. If it shows hot, it is too late. You can cook your AT and never know it. 4R100 is plenty strong, they fail from overheating. The tranny does have an accurate temp gauge built in, and you can access it with a Scangauge thru your OBDII port. But most people get 3 aftermarket gauges; pyrometer, trans temp, and boost. I have Isspros for example. Those gauges cover the info you really need. Most people also get an extra tranny cooler, the stock one is puny. Extra cooling is mandatory if you plan to tow. Search for threads or check FAQ, this is a well documented topic.