C4 Trans issue

[River City]

So my '61 uni came to me with a 351W with a C4 out of a '79 LTD, the motor fires off just fine, but I never let it run for any longer than 20 seconds or so as there is no coolant or tans fluid in the C4. Also the stock manifold dumps almost directly onto the stock steering box (I'll have to figure that one out later). When I got the truck, the guy before me had the the trans pan dropped and hanging by the dipstick tube, so I figured something was up with the C4. I got under it today and found I could not move the linkage at all with my hand, so grabbed a pair of vice grips to see about getting a little leverage on it, nada. The linkage is totally stuck, won't go into any gears or hardly budge. Asked my neighbor who has rebuilt a few older cars and he told me "Oh that means it needs a total overhaul, better pull it and rebuild" he can be a bit dramatic so I thought I'd come here and get a second opinion. The truck rolls free with the drive shaft hooked up so either it's stuck in neutral, or no fluid anywhere in there. I have debated just going ahead and going for a C6 as I do want to tow a 1-2 ton camper as well as throw some speed parts at the 351W but that's way down the line. Anyone have any thoughts? Ever ran into this?

[bruceandersson]

What's it look like when you look up into the transmission? If the pan has been off for an extended time, there may be corrosion issues that resulted in the stuck shifter. Even if it looks clean, its got to be dirtier than the inside of a tranny should be. I think a thorough tear down and inspection is the least you'll get away with on it, and if you do that you might as well throw in the new parts. You could look for a used replacement if your budget is tight, but that's another crap shoot.

[Michelle]

I think I would at least pull it down far enough to find out what the linkage was stuck and then go from there. Years ago I had a C-6 that I wanted to rebuild. I had a friend that rebuilt transmissions for a living come over to rebuild it for me. He gave me strict orders to have a work bench totally clean of any objects and covered with clean cardboard with a five gallon bucket of clean varsol. He stressed that everything had to be clean. So I agree with Bruce if it has been open for an extended period of time it probably needs to be rebuilt anyway.

[River City]

10-4, thanks so much for all the info Bruce and Michelle! I'll get on dropping it today and keep you updated.

[LM14]

If you plan on towing with it, I would just find a SBF C6 and get it rebuilt and sell the C4 as a core to help with your costs. Why spend money on a tranny you don't plan to keep? Spend it on what you plan to go to.

SPark

[HotRodMatt]

^^^^^^^ what he said c4 is no good for towing any significant weight. find a small block c6.

matt

[River City]

Exactly what I was thinking guys! Yanked the C4 today and going to look at a couple SB C6 cores in the morning, of course they are both "Worked great when parked" but been down that road, it's a core in my eyes Wow what a ordeal to pull it though, the cross member on my '61 Uni (originally a 6cyl truck, not sure if that makes a difference) prevented the trans from coming out the the back way. Had to pull the 351W then lift it out the engine bay. Fun times.

[Michelle]

Oh yes, been down that road before too. The trannys are not easy to get out. I found it easier to burn the rivet heads off the crossmember and remove the cross member rather than removing the engine. Then put it back together with grade 8 bolts.

[River City]

I debated that Michelle (and probably should have done it for future repairs) but had already planned to pull the front clip off to lift the body to address the rusty ol' cab mounts so I figured might as well pull the clip off now yank things out the front way, clean up that 351W that's covered in crud and makes addressing the brake system and front suspension that much easier while I'm at it.

[LM14]

I just remove the middle/bell housing cross member and get rid of it. With the added transmission cross member you will need and side engine mounts for the SBF, you don't really need that original cross member anymore. If you are concerned about strength, you can just box the frame from the front diagonal members to just behind the front cab mounts.

Spark