Thanks Sous, your quite the research wizard. I've got a suspicion that main detent plunger you posted above is the culprit. I did contact Midwest Transmission Center and their tech took the time to suggest that it might be hydrolocking and to pull and inspect it. He said he did have some good used ones. So I'll pull it and if the detent to those gates is absent that could be the problem - unless it's the interlocks binding. I ran a borescope down there the other day and didn't see anything obviously abnormal about them though.

I have to say that is probably the most annoying quirk still present, it's been a long road and a lot of weeding out, but getting closer to good driveability.

 

Your welcome and I hope the information at least gives you an idea of where the detents are located on the case.

Keep us updated and let us know how you get on with it. I am curious at the very least.

Good luck to you sir.

 

Well, well, something aint right... Sometimes that gut feeling doesn't lie. But what exactly failed?












I hope the detent pawl is fine. I hope the brass plunger was freezing up. I hope a new detent plunger will fix it. I hope...


A free exotic German beer and lunch goes to whoever can source a new one.

 

@Greasemonkee The detent I pictured above was on Ebay, here is the link.

Clearly used part, so perhaps your contact at MidWest should be called back?

https://www.ebay.com/itm/Main-Shift-...97.m4902.l9144

Look at the detent part image I posted above... It has NEARLY identical marks or scoring on the edge as yours. Perhaps this is not a good choice, but I will leave the link up so that you can see listing itself and compare it to yours.

I have used Transmission Parts Distributors in the past with great success for my ZF6. Upon searching for "ZF6 detent" on their website, several choices came up. I will post a link to the search results because I don't know for sure what you need. I did see several new pieces listed for up to $78, but they were new.

https://www.transmissionpartsdistrib...ery=zf6+detent

I hope this helps...

EDIT: This appears to be the right part you are looking for, but I don't know that for sure. https://www.transmissionpartsdistrib...gm-0501206040/

 

I think I owe you a lunch. Not sure how you do it, I never could find one. It did say limited availability, but the order did go through if that means anything. Thanks Sous.

 

Well, since you are in Hendo, which is just a short trip up the interstate from us, the next time we are up that way you can thank me in person if both schedules permit. The offer goes the other way too if you ever find yourself near Hartwell. No lunch or beer required, that is why this forum is a great community and resource.

Let us know how it goes!

 

That link is actually to my eBay account, PM me.

 

I just wanted to conclude this thread and state that the problem has been corrected with a new main shift detent plunger. It remains a mystery as to why the old one was seizing up with heat, but now I can actually use reverse and low gear with a hot trans. Special thanks to Sous.

Ford part # E7TZ-7E218-A

 

Outstanding news and you are very welcome. Thanks for closing out your issue with a part number and results.

Now you can smile instead of groan each time you want to shift into reverse or low gear.

 

Hi, I searched around and couldn't find a definitive answer and this seemed like the most appropriate place to ask this question. Can that main shaft detent retainer / plunger be removed for detent replacement without disconnecting anything else tranny related and presumably with the shifter in neutral? I have the exact same thing going on, only stiff and extremely hard to get to R / L after a long long drive and transmission very warm accordingly.

I know its a 3-1/2 year old thread, but it was 10 years old before that lol...anything to help me and the next guy?

 

Yes you can. Just loosen it up and turn it out and stick new one in. It's simple.

 

Thank you for the prompt response. I hoped it was that easy, just wanted to confirm nothing would fall out of place and neccitate a trans removal which I would not prefer haha.

 

It's been a bit since the old plunger has been in my transmission so I don't remember exactly what it was doing, but what may be worth mentioning is that the plunger will hydrolock after a few miles of driving. It is normal routine for me now to deal with it - just put steady and constant pressure on the shifter and it will squeeze the fluid out, then I can get over into that next detent. Even further, reverse or low rarely aligns to get through the gate, but if you can get it in one it will go through the other, so I usually have to bounce off the gate a couple times, but it always goes in. These transmissions are quirky, but it hasn't let me down yet.

 

I've noticed mine will also sometimes be harder to get into Low when it's really heat soaked from pulling a trailer but never gave it much thought. Always figured it was just kind of one of it's quirks. I will say it doesn't seem to like this Amsoil stuff I've had in there for about a month quite as much as it did the Redline MT-90. But I also think there's a chance some bearings are getting shot in mine, so it could just be that. Not sure how long these are expected to last. Probably a lot longer if the pilot bearings weren't such cheesy corner cutting junk in these trucks.