So I have been having issues with my C6, and I want to make sure it's not my converter or modulator or etc before I rip it apart.

When put in gear, it takes about 10 seconds to actually engage. When it does engage, it seems weak. Once up to speed it seems fine. No real issues climbing hills or anything.

What do you guys think?

 

Sticking or leaking seals in the valve body.

 

Alright thanks. You are 100% sure?

If I open the tranny to replace/rebuild the valve body, should I just go ahead and do a complete rebuild?

 

Can't really ever know until your in there. Once ya got it apart then you can do a visual inspection and see what needs replaced and what doesn't. If you'r anything like me, then money is tight. Replace what needs replaced and go with it. Only you can decide what the truck is worth to ya, and how long you intend to keep it. If it is something you intend to keep for years to come, then a complete rebuild wouldn't be a bad idea if you can afford it (I don't think c6's are too hard on the checkbook). It would suck to have to drop the tranny in a year because it wasn't completely overhauled the first time. Good luck to ya, hope you have good luck!

 

So the thing is, once I get the tranny apart I don't have time to let it sit while I order parts. So I'm thinking probably go ahead and order a rebuild kit, torque converter, and modulator valve tonight, and get it rebuilt next week. What do you guys think?

Am I missing anything that needs replaced?

How do you guys feel about shift kits?

Any special tools I should pick up/how tough is it to rebuild?

Sorry for the questions guys, but I am unfamiliar with automatics.

 

Is the fluid up to the proper level? Does the fluid look or smell burnt? Does it take 10sec to engage in both reverse and drive? Have you checked for vacuum at the modulator with engine at idle? Have you pulled the vacuum pipe off of the modulator and checked for any signs of fluid in the pipe?
When the trans does engage in Drive does it feel like it is taking off in second or is it slipping in first?

 

Fluid level is fine.

Fluid is fairly new.

Yes both reverse and drive.

Have not taken the vacuum line off, just checked to make sure it was still connected at both points.

And yes feels like it's tasking off in second or slipping, in both reverse and drive.

 

Unfortunately it does sound like rebuild time.
However I would advise you to go to the transmission page and post something like "C6, good fluid and fluid level but delayed engagement in forward and reverse and slips in both. Any advice." There are some great experts there and I would go on what they say.

 

I will try that. Trying to get a list of parts I need to order, but I don't know which rebuild kits and converters etc will fit.

 

Good thing about the C6, a full rebuild will not cost over 700$!

 

I need a valve body, torque converter, rebuild kit, modulator valve and new fluids right? Anything else I should add to the list? And can anybody point me in the right direction for parts? I have no idea which ones fit this tranny.

1987 F-250 XLT Lariat 4x4 Supercab, C6 transmission.

 

Not slipping at this point? How old is the fluid?

If it doesn't slip and the fluid is unknown age or known to have several hundred thou on it I'd try fresh fluid and filter before I called it dead and ready for a rebuild.

A look in the bottom of the pan will tell you lots about its condition regardless. If it full of junk, load with lining material 1/4" deep and scrape metal shavings all over the magnet then yea probably safe to say needs rebuilt.

The filter might just be dirty limiting fluid flow, has problems building full pressure initially because of it. Get it off, cut it open and inspect it.

Filter and fluid change is a cheap and easy test to see if its salvageable, if no help no big loss of money or time spent.

 

Fluid and filter were changed in it last year.

 

How many miles are on the truck/transmission?

 

165k ish miles on both. Original transmission, it has never been out of the truck. Have known this truck since the day it was bought.