Some question about transmission and steering
I don't use to visit the forum because I don't have spare time enought.

From a time I only use my car to enjoy it. I fill the gas tank and hear the V8 and play with my "toy". But now, I need to do a good maintenance.

I have some question, because the car is not matching number, and I don't know where could to get the parts I need. Further, I'm not exactly an expert in mechanics, but I like the "DIYs" and I'm learning slowly.

The point is that I need some parts:

- Rear Retainer gearbox. The car came from factory with the FMX gearbox, but now it has a C6. I wanna disconnect the transmission and mount the new seal and I hope to finish with dripping ATF by the part that goes to the cardan shaft.

- Front differential Oil Seal. (I don't know if it's the original one or not) The problem is the same case for the gearbox. Where the cardan comes and is introduced into the differential, it can be sought lubricant dripping from the front side. You can see the differential in the pictures. There isn't the metal steel with specs, so I don't know which is. Is only has a few numbers machined on the top (see the pictures), and I can not decode it. In the lower face of the box, there are machined too the number "77". ¿???

[Image: 150205035310428562.jpg]

[Image: 150205035344428563.jpg]

- Steering tie rods. In the picture you can see the striatum and I need the piece that covers it.
Further, the joint loses much hydraulic fluid. When going to take the car I find a puddle of a foot on the floor next to the front wheel (driver side). I've to refill the pump continuosly. I think I need the output axle cap of steering pump.
The steering is malfunctioning. Sometimes it goes well (a bit hard in my opinion), and other times you need both arms to move the steering wheel (very, very, very hard). For example when the car is parked. Do You know if I have to change the steering pump? or steering box for a new one?

[Image: 150205035405428564.jpg]

[Image: 150205035428428565.jpg]

On the other hand, does anyone know where I can get a complete cutting of the car where I could find all parts? my English isn't as good as I'd like, and when I buy parts sometimes it costs me a lot of work.

Sorry if it seem silly or obvious questions, but I'm just a beginner and need help from people who know well the car.

Thank you very much in advance!

Best regards from Spain,


P.D. Sorry for the pictures size!

Hey Roberto. I will need to know the year and model of your car to give a complete answer. The transmission swap shouldn't affect the rear end. The front steering box is usually a complete part swap for novices. I would check with for the steering gearbox. Sometimes you come out cheaper in the long run. Leaky gearboxes aren't always just seals.

The rear center section is a small axle 9 inch pinion seal. The seal an is very affordable. Buy two in case you're not comfortable and mess up.

You can do this by only pulling the driveshaft and the Yoke off the Rear End. Go ahead and replace your u-joint if you're comfortable with that. Otherwise tape the caps on with electrical tape. After removing the yoke Nut, Pry the yoke off with a pry bar or a Rubber Hammer. Use a seal remover tool to remove the seal. You can use a sand filled dead blow hammer to tap the new seal evenly or a seal driver in to the center section. Install lubed yoke and tighten new yoke nut to 25 inch pounds or 11.34 KG.

Hope this helps. Good Luck.

I recommend a fluid swap since your center section is leaking.
I'm very grateful with your fast response "1973mach1351c".

I bought the car, and I'm discovering continiously that the car has some parts changed. I'm not an mechanical expert, so i'm not sure about references I've to order when I need.

Sorry, I forgot to give more specs about the car.
The car is a mach1 351C (1971). The first VIN digits are 1T05H......
I think than the rear axle is a 9" from factory.

Here you can see another picture of the rear axle.

[Image: 150205084757428736.jpg]

I'd like to know about this "counterbalance" that is screwed to the gear box. It's the first time I've seen that. Have you ever seen anything like this??

[Image: 150205084813428737.jpg]

[Image: 150205084832428739.jpg]

Best regards,


Wow! Never seen that before. I doesn't go to anything but air. I would say the same as you. Maybe it reduced vibration on whatever the transmission used to be in or was just cut off and left on in the car. I would remove it since it adds weight to the rear of your trans.

Plus you need to change the rear seal on the trans at the same time you replace the pinion seal on the center section. Measure the output shafts dimension and you'll get the right part when ordering for a c6 in a 71 to 73 mustang with a c6.

You have a H code Mustang.
Hey Tommie,

It looks as though 1973Mac1351C has given you some great help. (Thanks 1973Mach1351C)

Si todavia necesita mas ayuda no dude en pedir.
Thanks for your response!!

Sorry, I can not visit the forum as much as I'd want.

Best regards,

Roberto Wink
I have seen (and removed) those counterbalancers. They are to reduce vibration, but were not very common. Maybe a trial part. They were replaced by a metal and rubber ring balancer ( similar to a harmonic balancer on the engine). The balancer is on the transmission output yoke, and looks like it would reduce vibration. I installed the balancer equipped driveshaft and C-4 from a 1976 Granada in my 73 Mach1.
When you replace the pinion seal on the rear axle. The pinion bearings inside have a slight preload which is set by the pinion nut. Without the required tools to measure the preload on the pinion bearings, its common to closely note the position of the pinion nut before removing it. Mark the position of the nut with something, white paint, center punch, etc. Then when reinstalling the pinion nut, tighten it until it's at the same position it was originally. Slightly tighter is usually okay, slightly looser is usually not okay. If you accidentally go slightly tighter, its best to leave it and not loosen it.

The torque number of 25 in. lbs. in another post sounds more like the measured rotating torque which is how the bearing preload is measured. So, retightening the pinion nut to the same position it was in originally is safer without the proper tools.

Lastly, if you have red Loctite thread locking compound, put a little on threads before reinstalling the nut. It prevents the nut from working loose over time. It is available at any auto parts store.

Best Regards,
Your steering box needs a pitman arm seal. It can be purchased from an auto parts store. It is retained in the steering box by a snap ring. The new seal will (should) come in a kit with a new snap ring and several spacer-washers. You will need a puller to remove the pitman arm to access the snap ring, washers, and seal. Make sure to mark the arm before removal to assure it goes back together the same way it came apart. I'm pretty sure it will only go on one way (as the splines allow), but who knows who's been there before you. The seal will be stubborn to remove. What I've done in the past, is : #1. Make sure your power steering pump is full. #2. Mark the sector shaft and pitman arm so re-assembly is duplicated. #3. Remove (separate) center link from pitman arm. #4. Remove pitman arm from the shaft with a suitable puller. #5. Remove seal retaining ring and washers. #6. Start the engine and run about 2000 rpm while turning the steering wheel left and right. The fluid pressure should blow the seal right off the shaft (assuming the power steering pump works properly.) If all this sounds like a lot of work...... well, it is. aka sweat equity. If you don't feel comfortable doing this, any reputable shop should be able to. By the way, you'll need a new differential filler plug too, that one is destroyed. +1 on 1969_mach1's advice.
The filler plug might be hard to remove. The plug on my car was the same. Here is what I did.
Make a slot across the plug with a dremel tool, using a small disc.
Use a gasket scraper in the slot, turning it with a wrench.
Use some sealant on the new plug, don't overtighten.

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