Shift rail plungers

[Jim.UT]

I have two 850's. One of them is just starting to jump out of 3rd when not under load. The other does it much more often. I'm thinking it's time to replace all the shift rail plungers to see if that fixes the problem before going any deeper into the transmissions.

Question: I seem to remember reading here that there are 3 of these parts needed (P/N NDA7233A). However the New Holland parts site indicates that 4 are required (see item #10). Since my NH dealer is likely going to have to order these, I'd like to get enough the first time. So for two tractors, should I order 6 or 8?

Next question: What is the liklihood that I also need the associated springs (item #11, P/N 83407013)?

Third question: Why would the parts site only specify 1 of the gasket in the assembly? See item #12, p/n E5NN7Z307AA. It looks like there should be one gasket per plunger assembly.

Thanks!

 

[GVSII]

I think the forth one is for the draft/position control lever.

 

[Harry in Ky]

By all means replace the springs. A weak spring is probably a bigger factor than the plunger condition anyway. If that doesn't help, you've got shift collar/gear problems, or too much endplay between gears.

 

[Dean]

You will need 3 for each tractor. Replace the springs as well.

Note: Replacing the springs and plungers will have little or no effect if the transmissions are jumping out of gear under load.

Be sure to also order the compressed paper gaskets that seal the caps.

Dean

 

[Larry-NEK]

Jim, there are only 3 plungers and springs, one for each shift rail. The third-reverse plunger (detent)is the first to go as it gets the most use. The first-second on my 860s all looked brand new. The dealer may only sell 4 to a package, can't remember. Larry

 

[awhtx]

There are 4 plungers. I don't recall where the 4th one is (maybe on the Up and Down movement of the shifter). I'm not at home or I'd go look. The 4th one looks exactly like the others so if you look on the side of the trans case you will find it.
Before you go buy new ones here's what I'd do. As another respondent said the 3rd-Rev plunger gets the most use and wear so I'd remove it and swap it with the 4th-5th plunger since it gets the least use. See if that fixes the jumping out of gear problem. If your luck runs like mine it won't fix it and you will be disassembling the entire transmission to replace the 3rd-Rev sliding coupling.

 

[Hobo,NC]

If you CAN NOT hold it in gear with modest pressure its notcher detent... I like the ID of swap'n parts and like to be proved wrong... Hope it works out fer ya...

 

[john_Bud]

I only replaced 3... where is the 4th?

Here's pictures of the old right next to the new. Significant wear and the sift feel changed dramatically after the swap.

 

[john in la]

I think I would follow Alan's advise and switch plungers around and see if that helps.

The spring is the same one as on the PTO plunger; this is the reason they list 4 needed.
The book is wrong with the gasket. Read what it says......
#12 1 E5NN7Z307AA GASKET O-Ring, Pressure Tube Between Center Housing & Transmission Case, Start Year: 01/01/1955

If you order the parts order them by discription; not the numbers. Let the dealer order what he thinks is right that way if it is wrong it is his problem. I think all these parts come 5 to the bag. You might have to buy full bags depending on your dealer.

 

[souNdguy]

yep.. my dealer sold em by the bag.. and every bag he had they were rusty too.. go figure.. just orange surface rust. . no pitting.. but still had to polish them before use..