Transmission shifting hard
 

Hello everyone. My truck has started shifting hard recently. It started doing it on the shift from 1st to second and now it seems to be hard shifting on all gears. If I am stepping on it at all, it feels like it is going to drop the tranny in the road. This is especially true while at highway speeds when passing a car or similiar. I bought the truck used and do not know if it has a chip or a kit. I don't even know where to look for a chip. I did read about a kit that will "firm up" the shifting...maybe it had one of those and it has become defective, not sure. The truck has 300,000 miles on it and I drive 90% highway miles at 70-75mph. Any input would be greatly appreciated.
Thanks

Since the problem started recently, I don't think it is PCM related. Sounds more like a sticking valve or spool. There is a plunger in the line pressure modulator that could be sticking and 'boosting up' the pressure.
Have you changed the fluid lately?

Thanks for the quick reply. It has been about 70K since the fluid was changed. Do you think that is the place to start?

With that many miles, it would be a good place to start. Have you ever done the transmission flush (instructions by Mark Kovalsky) or had it flushed?

No flushes. Just a filter/fluid change once. Where can I find the Kovalsky flush thread?

Here ya go.


Changing ATF Fluid in a E4OD and 4R100 transmission .: Articles

Changing the fluid and a flush is definitely the place to start, my transmission shifts OK and after a flush and change I can really feel a difference, I change my trans oil quite often, almost every two oil changes.

70K is a bit long between flushes/filter changes. 35K is what's recommended. A complete flush and filter change will get all the fluid out too.

Actually, 30k is the recommended interval.

How do I know whether I have a E40D or a 4R100 or a 4R70W? It is a 1999 7.3 F250 Super Duty Powerstroke.
Thanks for all the help so far.

You have the 4R100.

the guy at advanced auto says he shows no 4r100 for this make and model. The only filter he has is the E40D. Are the numbers on the tranny anywhere? I would like to be sure what I have before taking it apart. Thanks

Go to another auto parts store. It's a 4R100 tranny.

Opps, sorry Mark, you are absolutely right - 30K between flushes. I was mistakenly thinking that he was exactly 2 times over the limit on mileage. duh. At least my math skills were working just not my maintenance skills.

I noticed in the article that was posted that it says to use mercon instead of mercon v, but didnt they phase mercon out?

They re-formulated the current Mercon to be compatible with all the internals of a 4R100.

This reminds me, time to pull a tranny oil sample for Blackstone. Thanks!

Yes, it's cheaper than an oil change, and more environmentally-friendly than a complete change-out.

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