Changing Pumpkin

Don't know if Ishould post this in the maintenance forum but the

change will affect performance

The car came with a 3.25 "standard axle ratio" which I later found out

was mandated by the air conditioner. Still only one wheel driven.

The person I bought the car from exchanged that pumpkin for a

2.75 Traction-Loc because he did a lot of highway driving.

In the next few days we will be changing the current 2.75 "posi"

with a 3.50 Trak-loc. That should give the rebuilt 351C 4V with

a "mild" cam, 770 Holley and toploader a little more snap at the

accelerator pedal. Besides 5 pints oil and a new gasket what other

parts will I need? There is mention of "axle seals" and my mechanic

is fretting about the condition of the c-clips. I have not been able to

find a source for c-clips. Any suggestions were to find these?

mike

Don't know if Ishould post this in the maintenance forum but the

change will affect performance

The car came with a 3.25 "standard axle ratio" which I later found out

was mandated by the air conditioner. Still only one wheel driven.

The person I bought the car from exchanged that pumpkin for a

2.75 Traction-Loc because he did a lot of highway driving.

In the next few days we will be changing the current 2.75 "posi"

with a 3.50 Trak-loc. That should give the rebuilt 351C 4V with

a "mild" cam, 770 Holley and toploader a little more snap at the

accelerator pedal. Besides 5 pints oil and a new gasket what other

parts will I need? There is mention of "axle seals" and my mechanic

is fretting about the condition of the c-clips. I have not been able to

find a source for c-clips. Any suggestions were to find these?

mike

Click to expand...

C clips should be fine but I would change the copper washers that goes on all the studs. Find out if you need any additives also

Hello,Get a knew machanic,there are NO c clips in a 9 inch ford,just 4 nuts that hold in the axle on each side. and do not worry about the copper washers just use a good housing gasket.

Chris

Like the other post said there are no C clips in either the 8" or 9" rears. When its pulled apart its worth the time to replace the axle seals and also check the axle bearings and replace if needed!

Thought this was what he was calling the c clips

http://www.jegs.com/i/JEGS-Performance-Products/555/62730/10002/-1?parentProductId=1528642

Guess they are bearing retainers:blush:

Personally, I don't use a gasket or copper washers. Just garden variety clear silicone.

It is a very simple job. One warning, not all center sections have fill plugs. If the one you have doesn't have a fill plug, our cars housings do not have plugs either and you can end up with a mismatch. It is not a big deal as you can drill and tap the housing for a pipe plug at the same level as your housing plug- don't go higher or you risk overfilling.

Car in neutral, lug nuts just broken loose, jack car up and place rear axle on Jack stands, remove the rear wheels and rear brake drums. Using the access hole in the axle remove the 4 bolts on each side. Go under car and unhook the rear U joint and move it out of the way. Loosen all the nuts around the housing, the bottom two in the corners will need a open end wrench. Place a catch tray under the center section and with a rubber mallet just break the seal on the old pumpkin and drain as much fluid as you can. remember, right now the axles are still in place to keep differential fluid from getting on your brakes when you pull the axles, so don't go to pulling or beating on it.

Now take a piece of saran wrap about 3 feet long and wrap the brake shoes covering the friction surface but leaving everything in the center open. Put a brake drum on backwards and tighten the lugs just snug and use the drum as a grip to pull on the axle. sometimes a rubber mallet helps it to get started. Pull the axle all the way out and set it up out of the way. you can leave them in and just pull them out enough to free up the center section, but the axles laying on the axle seals will potentially damage them.

If the axle seals are in good shape there is no point to changing them, if they are not, bearings are probably called for as well at this point and will need to be pressed off and on by a machine shop.

With both axles removed, pull the old center section forward. You will need to work it forward evenly to keep it from binding on the studs. It is about 70 pounds so a jack is very helpful.

Once it is out clean the mating surface, use a fresh gasket or the sealant you prefer and pretty much reverse these directions. Last time I did one at home by myself with no power tools it took less that two hours.

just a note

c clips are used in period 10 and 12 bolt chevys to retain the axles

Jenny

Thought this was what he was calling the c clips

http://www.jegs.com/i/JEGS-Performance-Products/555/62730/10002/-1?parentProductId=1528642

Guess they are bearing retainers:blush:

Click to expand...

Thanks for the heads up. I may order a couple of those.

Have no idea what my mechanic means by "c-clips" but

he is fretting about it. Will show him your picture, but

I think that's them. He has already replaced the pumpkin

once on this very car when a 3.25 was swapped for a 2.75.

mike

Tnfastbak is correct in the calling them c-clips. Don't get Chebby tunnel vision on the axle keepers. If they were stressed on the rebuild they will need replaced. IMHO (did you know that any bolt that has been torqued to the propper pressure cannot be re-used. The threads are stretched such that they will not hold suffieciently on the second attempt and may actually cross thread) Just a little info on the side.

Personally I use both the copper washers (hardware store copper plumbing washers work fine) and the gasket. I think there is a reason Ford put them there. Just my way of doing it.

Use the copper washers. They were still available from Ford a few years ago. Chuck

Use the copper washers. They were still available from Ford a few years ago. Chuck

Click to expand...

Or Summit Racing

Tnfastbak is correct in the calling them c-clips. Don't get Chebby tunnel vision on the axle keepers. If they were stressed on the rebuild they will need replaced. IMHO (did you know that any bolt that has been torqued to the propper pressure cannot be re-used. The threads are stretched such that they will not hold suffieciently on the second attempt and may actually cross thread) Just a little info on the side.

Click to expand...

I think some members are confusing c-clips with snap rings.

In that case they are correct, there are no snap rings in the diff.

When we installed the new long block my mechanic got new bolts

for the intake/exhaust manifolds. So maybe he really does know

what he is doing

mike

Tnfastbak is correct in the calling them c-clips. Don't get Chebby tunnel vision on the axle keepers. If they were stressed on the rebuild they will need replaced. IMHO (did you know that any bolt that has been torqued to the propper pressure cannot be re-used. The threads are stretched such that they will not hold suffieciently on the second attempt and may actually cross thread) Just a little info on the side.

Click to expand...

He might be referring to the late model Ford 8.8 axle used in the 79-up Mustangs. It has an integral carrier rear end that uses C-Clips to hold the axles in.

The 8" and 9" used in the 71-73 Mustangs doesn't use C-Clips as we all know.

The nuts are special too.

Item #1080

65-78 DIFFERENTIAL CARRIER HOUSING WASHER KIT

11 Copper washers. Price: $4.00

Item #1079

65-78 DIFFERENTIAL HOUSING FASTENER KIT

Lock nuts and copper washers. Price: $12.00

I use the copper washers. They are there to stop leaks at the threads of each stud. Many guys don't use them. Yes, you will need ford friction modifier. Dont get the cheap stuff. Even the chevy guys:dodgy: buy the Ford specific modifier, it is just a better product.

It's not a hard job. If I can give you any advise, take your time, try to be clean thru out the job. What I mean by that is if you get any gear oil on you or your clothes, plan on throwing them away, you will never get the smell out of them. Ask me how I know

But I need my hands.

Hey Mike -

When you replace the pumpkin, I think you'll probably have to change U-joint and speedometer gear. That's what I had to do when I went from 2.75 to 3.50 on my 'vert.