Help on a C-4 auto tran
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Author:  Hwmerc [ Sun Mar 25, 2007 2:43 pm ]
Post subject:  Help on a C-4 auto tran

Hi All, I am back with another little problem :oops: The engine and fuel system is running great. Now I haven't been on the road with my truck for any distance greater than about 50 yards since everything was rebuilt including the tranny. So now that everything looked good, out I go down the street see how everything runs. Well the trans will not shift into the cruising gear. Fluid levels are fine. I have checked the vacuum and it is within spec. The vacuum modulator on the tranny is new. The travel on the linkage seems to be good, I can feel the notches when it travels thru the gears. But it just won't go into 3rd I guess, it auto shifts fine from low to 2nd, but just stays there, won't go into cruising gear. Now the really bad news is the place where it was rebuilt went out of biz 2 years ago.
Is there something else I can check, tweek or adjust on my own before I have to take it to the locals here. In this town, there aren't that many tranny shops and they charge up the ying yang compared to down in LA and no La is too far to drive in second gear unless I want the motor and tranny to sieze up.
So any help or suggestions please let me know, either by email hwmerc@yahoo.com or by phone 1-661-946-0523

Author:  Jim [ Sun Mar 25, 2007 5:17 pm ]
Post subject: 


I am no C4 expert but are you sure you have the linkage hooked up correctly. Sounds like it is in second instead of high.


Author:  Hwmerc [ Sun Mar 25, 2007 8:07 pm ]
Post subject: 

Yeah, I checked the linkage, it moves to all the settings, can the problem be in the bands, ie adjusting them?

Author:  Jim [ Mon Mar 26, 2007 5:17 pm ]
Post subject: 


I wouldn't think the bands but again, I am no C4 expert. Hopefully, someone else here has an answer for you.


Author:  Hwmerc [ Mon Mar 26, 2007 9:08 pm ]
Post subject: 

Jim, thanks for looking. I took it to a tranny shop this morning. He suggested a couple of things to check out, but they didn't help. He said if if they didn't work then it's probely in the valve body, something screwed up there. So I am taking it back in the morning to have them take a deeper look. Keep your fingers crossed that it's not some thing major. It cost 385.00 to get rebuilt a couple of years ago and I think the guys did something wrong, since that's the reason they went out of biz. They were being sued left and right about bad repairs and such. I didn't know about it before they went out of biz, just my luck. will update later in the week with more info. and if I have to leave my arm or a leg there :wink:

Author:  econoaddict [ Mon Mar 26, 2007 9:22 pm ]
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Probably a stupid question but have you tried to manually shift it through the gears?
if so what happens when you shift into drive/3rd ??

Author:  Hwmerc [ Tue Mar 27, 2007 7:38 am ]
Post subject: 

Dean, long time no hear :D
Yeah went through that too. Start out in low shift the lever to 2 it shifts, shift the lever into 3rd nothing happens, it just stays in 2nd. Have been underneath when the lever was put through all the settings , it goes into each of them fine and have disconnected the linkage and manually moved it through all the settings, everything appears to be fine in that respect. Vacuum is sitting around 16 to 17 since I am at about 2100 Ft ele. I guess it could be the modulator, but when I start out in drive, it auto shifts fine to second but won't go any further. I even disconnected the kick down to see if that linkage was off but no luck. I only have so many tools and knoweldge to check it out. So I am off to the tranny shop this am :(

Author:  Hwmerc [ Tue Mar 27, 2007 2:53 pm ]
Post subject: 

Well, just got a call from the tranny folks and they say nothing is wrong. It seems that the rear end which I thought was a big nine incher, yeah I know men always think big :) is not and the tranny shifts ok thru all three gears, it just seems like it is screaming at 60 65 mph. Well don't I feel like the total idiot :oops: :oops:
This is the first van I have had that had the small gear ratio. So I would guess that this is not a highway cruiser.
Anyone else out there have one with a 240 and smaller ratio? I am curious about what kind of gas milage you get driving around town. Also, anyone have a spare higher gear ratio pumkin laying around that they want to get rid of???
Thanks to all who had kind words and suggestions, my kind of folks :D

Author:  Jim [ Tue Mar 27, 2007 4:44 pm ]
Post subject: 


We have all had those 'DUH' moments so don't worry about that. Do you have a 9" in there now or a 7 1/4 ? I am not sure from your post - I get confused easily :-)


Author:  Hwmerc [ Tue Mar 27, 2007 5:48 pm ]
Post subject: 

Jim, The houseing is the one for the big 9 but the guy at the tranny said it was more like the 3.73 ratio???. He also said a lot of the service vehicle from that time period had the smaller ring and pinion gears installed in the big housings, that way they could change it later if need be, since they were only used for local driving. Or it could be that one of the previous owners replaced the pumpkin with a smaller ratio????

Author:  Hwmerc [ Tue Mar 27, 2007 6:45 pm ]
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Ok, looking at the manual, like I said I have the removable carrier, the book lists 4 possible axel ratio's
axel ratio ring gear teeth pinion type of gear set
3.50:1 8 3/4 35 10 partial non hunting

4.11:1 8 3/4 37 9 hunting

4.57:1 9 32 7 hunting

3.00:1 9 39 13 non hunting

I had some pics of the rear end torn apart which had shots of the ring and pinion but I can't find them, I thinkI lost them when I had a crash a couple of years ago.

Author:  Hwmerc [ Tue Mar 27, 2007 10:24 pm ]
Post subject: 

You know the more I think about it, something doesn't seem right. Now, I am no dummy when it comes to econolines and being 53 years old and having worked on cars for a lot of years. Someone tell me how when you place the gear knob in the lowest position ie 1st, then move it one knotch up and the tranny shifts, then you move it one more notch and there is no upshift, there is no way that it has gone thru 3 gears and is in drive???? or can it? This tranny place I went to has been in biz for a lot of years and they come highly recommended... but I can't seem to wrap my head around this, I could maybe believe it when and if I had the small rear end, but the big nine incher... I don't know. Anybody out there with C-4 and rear axel experience?? I dug out the invoice for when I had the pumpkin rebuilt and they even wrote 9 inch on it :? :?

Author:  Hwmerc [ Wed Mar 28, 2007 9:56 am ]
Post subject: 

Ok, here's some info that some may know and some may not. This particular c-4 tranny, has two markings on the column. One has a small dot and one has a bigger dot that is green in the center. I took the beast to a different shop and went with them on test drive. If you put the gear shift on the small dot it starts out in 2nd then shifts to third. If you start out with the lever on the big green dot, it starts out in 1st then shifts to 2nd then 3rd. I had been driving in the small dot so I only felt it shifting once.
Boy talk about feeling dumber than dirt :oops: :oops: :roll: Thanks to all and forgive my dumbness

Author:  Jim [ Wed Mar 28, 2007 4:47 pm ]
Post subject: 

Rusty, Welcome to the wonderful world of the green dot C4 ;-). For those of us raised in trucks that had them no problem, but to those who learned on PRND23 C4's they can have a learning curve. You are not the first to have some confusion with them!


Author:  Hwmerc [ Wed Mar 28, 2007 9:41 pm ]
Post subject: 

Jim, thanks for the good humor. The really great news is that I just sold it to a couple of real nice brothers from Downey in LA. They had been interested in since I posted the for sale on it. I got a little misty eyed to tell the truth :cry: , it was running so great. But the medical bills were getting a little tight. Besides In a couple of years I'll do it again, I really enjoyed rebuilding it especially the motor. But oh well, I still have the 66 supervan to work on.

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