Another C6 Question -- Intermediate Servo

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Sep 13, 2017 | 11:17 AM

LFDavidson

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Tuned

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Another C6 Question -- Intermediate Servo

Another issue I ran into is trying to understand the correct intermediate servo. Again, this is a 1988 F250 with 7.3L diesel. I noticed that the servo piston has a rather hard rubber seal. It has the big rubber seal and not the two ring type. It is marked "N" on the case. The servo arm is marked "K". Is this correct for this application?? I want to order a new one since the rubber seal seems like being hard that it will leak past the piston.

Thanks.

Sep 13, 2017 | 01:44 PM

Braggs

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Yes, replace the servo too. You are right that the seal gets hard and fluid leaks past the piston. Get a new servo according to what is marked on the servo cover. The "K" marked lever can be changed out for harder/softer shifts but this may/may not be necessary for your application. Here's a website that talks about the different types and the aggressiveness of the shifts for whatever combination you like: https://www.7173mustangs.com/thread-...vos-and-levers

PS: the rebuild kits have o-rings and gaskets for all the different variations of the C6 transmission (including tail housing, clutch count, and servos). Use only what matches your setup or customize if you like. For instance, I changed out the retaining ring with one that was notched for an extra clutch/steel since it was already in the rebuild kit. The transmission shop I went to didn't have a notched reverse retaining/reaction plate so I didn't do that one.

Last edited by Braggs; Sep 13, 2017 at 01:46 PM. Reason: added webpage for reference

Sep 13, 2017 | 05:06 PM

LFDavidson

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Great, thanks. I am guessing this is factory original. So, I will see if I can find somewhere to order a new "N" servo. Those don't seem to be something that most auto parts carry.

Sep 13, 2017 | 05:11 PM

LFDavidson

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Ok, so now that I am looking for a new piston, I see where they have different colored dots. What does that mean? I assume the "N" is the cover but the colored dot means different pistons??

Thanks.

Sep 13, 2017 | 09:42 PM

LFDavidson

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Going a bit in circles here. I just found on another site where they were calling the "K" lever crap. I know there are a lot of opinions across the internet but looking for a good recommendation. I don't know if this was the factory original setup. If it is, then I am good with the N and K combination. Since I need to replace the servo piston can anyone recommend the best set up for this truck. I use it for towing as well as around town.

Thanks.

Sep 14, 2017 | 09:05 AM

Braggs

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The "K" lever is the one of the softest shifting levers of those on that site I posted (meaning it will slip the clutches more than a firm shift). It's up to you whether you will swap that out with a firmer shifting lever. Just one of many customizations you can do.

A quick search online found a piston for $15. There's a couple transmission supply houses here in my city where I went in-person to buy my servo replacement. You could try the same in your area.
C6 N Code Servo Piston - Broader Performance

Sep 14, 2017 | 09:48 AM

LFDavidson

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Thanks for the info. I am surprised that it is one of the softest shifts considering it's a diesel and heavy truck. However, I am tired of the slam into gear that was likely caused by the Modulator and/or VRV on the truck anyway. In fact, I think that is what caused the damage to the transmission in the first place. Clutches were heat cracked and smelled burnt with lots of sludge from clutch material.