Author Topic: 1973 C4 rebuild and upgrade (Read 4626 times)

dave1987 · « **Reply #30 on:** May 28, 2011, 01:35:40 AM »

I fixed the leak today! It was the rear (return line) 90 degree fitting. I forgot to put an o-ring inside the female side where the line screws in. For extra precaution I wrapped some high density industrial grade thread tape around the threads of both the line nut threads and the male fitting threads to stop any leaks. All sealed up now and working well!

Now I'm afraid that the condenser might have been a step to far in this project, as it may be blocking flow some due to it's small internal passages. I may be swapping out the condenser for a F-250 oil cooler in the near future, we will see. I need to call around to some tranny shops and get their advise on the topic.

dave1987 · « **Reply #31 on:** June 26, 2011, 11:19:45 PM »

So I noticed a leak today.....

The output shaft seal at the end of the tail shaft seems to be leaking, as I have fluid all over the tunnel under the car!

I have a new seal, and new bushing, why is this happening? Is there a such thing as a drive shaft repair sleeve that I could use to remedy this?

RSM · « **Reply #32 on:** June 26, 2011, 11:54:10 PM »

Hows the balance on the driveline? Any vibrations?

dave1987 · « **Reply #33 on:** June 27, 2011, 12:26:50 AM »

There is a vibration while going from 35-40. Think the drive shaft needs balanced?

Srt · « **Reply #34 on:** June 27, 2011, 02:28:47 AM »

i am reading it too! & i think you've taken a lot of the mystery out of the task of working on & maintaining automatic transmissions

RSM · « **Reply #35 on:** June 27, 2011, 11:13:17 AM »

I would pull the driveline and have it checked and install a new seal and bushing just to save more headaches down the road. The yoke could also be an issue and a driveline shop can check it out for you. The vibration could also be tires. How old are they and when were they balanced last??

dave1987 · « **Reply #36 on:** June 27, 2011, 12:18:29 PM »

Well then it sounds like its time to check that driveshaft. The tires are new as of the 20th. Balanced and all!

FCANON · « **Reply #37 on:** June 27, 2011, 12:28:03 PM »

I've had new U-joints that were crappy... Just say-n!

FrankBoss

dave1987 · « **Reply #38 on:** June 27, 2011, 01:06:14 PM »

I was wondering about the U-Joints, myself, not entirely sure that was the case though.

I have rebuilt the transmission, swapped out the rear axle for one that is known to be vibration free (was in my 78 sedan, originally came from a 73 wagon as well though), new U-Joints, new transmission and motor mounts, and new tires with freshly balanced rims.

The only thing I have not have professionally tested yet, is the drive shaft. If that's not it, I don't know....

I have a shop who will spin balance my drive shaft for $70.00. Isn't that a bit expensive though?

RSM · « **Reply #39 on:** June 27, 2011, 03:04:23 PM »

I had a driveline built for my drag car when I installed the 9" I can't remember what the cost was but $70 might be in the ballpark for a balance. Just make sure and have them check the yoke real good...might be worn where the seal runs on it.

NJford · « **Reply #40 on:** August 16, 2011, 11:47:55 PM »

If seal still leaks check the slip yoke make sure its not worn and also check the spring on the seal are know to pop off when installing seal. One trick to void come backs is to pack seal with petroleum jelly and put into freezer for 20mins then install.Also you can tighten the spring alittle if your slip yoke is worn by turning spring apart and cut 4 coils off the female end and turn male end back in and reinstall. I hope this helps you.

dave1987 · « **Reply #41 on:** August 17, 2011, 01:38:13 AM »

Thanks for the great input NJford! I never would have thought to tighten the spring any! I will be replacing the tail shaft bushing one more time just to be sure that isn't a culprit in all of this. Also will be doing the spring tightening with the seal and installing it with the petro gel and freezing it. Actually I might as well do that while I have the tail shaft off so I can tell for sure if the spring comes off or not.

Again, thank you. I have been researching this problem for weeks and never found anything this useful. Glad to have you on board with the Pinto community! This is what we're all about!

dave1987 · « **Reply #42 on:** January 26, 2012, 06:34:13 PM »

So for the past two months I have been working off and on rebuilding the transmission that Walt gave me but failed shortly after. I believe I found the culprit to it all as well. It seems there there was negative end play and everything was mashed together. It is surprising it lasted as long as it did! When I pulled apart the clutch packs there was absolutely NO lining left on the clutches for the direct drum, but the rear drum seemed to be just fine.

Also, the LEAST noticeable damage was the sun shell. It seems that the negative end play forced the end of the sun shell inwards, making the end of it concave instead of flat. I spent an hour an a half trying to figure out why I couldn't get the sun shell tabs to lock into the direct drum tabs.

I managed to locate a good sun shell locally and here is the difference pictures:

Pic 1) You can see the bowl type warping in the old shell's base in this picture

Pic 2) You can see where the forward planetary gear set was actually making contact with the inside of the sun shell. That's a lot of force required to bend the shell in that much!

pic 3) Here you can see how much the sun shell's bushing wear plate was bent due to the negative end play.

pic 4) And here is the difference in the plates when removed from the sun shells.

dave1987 · « **Reply #43 on:** January 26, 2012, 06:44:44 PM »

Pic 5) Now you can see the most notable difference between the good and the bad shells.

Pic 6) Until I get back to the garage next week to reassemble everything, I wrap the parts in plastic wrap to keep them clean, an to keep any oils or fluids from making a mess at home! (this is how I store parts in storage as well)

Pic 7) For reference, these are the valves assemblies that get sticky from dirty fluid, or the valves themselves start to wear after time. When rebuilding your transmission, be sure to remove the valves and clean the valve body and governor well. Sediment and fluid turns to a paste like substance and gums itself into places it shouldn't be. To polish the valves I use Mother's Aluminum and Mag polish on a microfiber towel, then stick the spring end of the valve into a cordless drill chuck and wrap it with the polishing towel. If no spring end is available, I just polish them by hand the best that is possible. It works very well and gives amazing results!

johnbigman2011 · « **Reply #44 on:** January 27, 2012, 01:31:17 AM »

Dave, I'm impressed. I know you must of mentioned it somewhere in all the detailed instructions that you provided. How do you change the shift seal? My C4 is leaking around the shift linkage going inti the side of the trans.

dave1987 · « **Reply #45 on:** January 27, 2012, 03:04:46 AM »

First off get a pan gasket and filter kit, miht as well change the filter while you have the pan down.

You will need to drop the pan at the rear and let the fluid drain out into and oil pan, discard that fluid. When its done dripping, remove the large head bolts to drop the valve body, more fluid will drain so keep your pan handy!

Once you have the valve body out you need a 3/4 inch open end wrench to take the shift shaft bolt out, be sure you have the neutral safety switch and the linkage removed as well. Once the nut is off you can withdraw the ahift shaft out the side of the transmission.

Pry out the seal from the outside with a flatblade screwdriver. Now two in the new seal flush with the casing.

Assembly is the reverse of the disassembly.

Don't forget to lube the new seal and the shaft with trans fluid before installing the saft again.

Also, you may need to drop the trans mount to let the transmission down enough to withdraw the shift shaft, or it may run into the tunnel.

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Author Topic: 1973 C4 rebuild and upgrade (Read 4626 times)