Long sitting/no usage, rear axle

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greymouser7

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I have an axle of unknown quality.

It came from a 1976 Plymouth Volare Road Runner E58 car. This car was driven hard and abused. The axle is an 8 1/4 with a Sure Grip Unit. 2.94 gears. It is going into the Dodge Aspen that I am restoring. The trans will be a cast iron 833 Over drive unit and the motor will be a 360 with a XE274 cam.

I took off the backing plates, pulled the axles and gave the axle a once over look.

The gear oil inside the differential looked great despite the fact that the vent plug/hose was not installed. Just an open hole that was caked over/covered in an oil-mud brick mixture.

I am refilling the gear oil with synthetic Sure Grip gear oil.

Is there any concern regarding the clutches on the sure grip with regards to some sort of preventative maintenance?

Any recommendations?

Thank you very much!
 
With that cam you may want to bump your rear gear up into the 3.55-3.91 range since you have the OD trans. That will also answer any questions you may have about the Sure Grip since you will have it out for a gear swap...
 
Dear (seemingly pseudo) bad-tempered, difficult, cantankerous person,

My first gear is a 3.09 X 2.94 gears = 9.0846

A regular 833 is 2.66 X 3.55 gears = 9.44

In my heavier Road Runner, I felt that 1st gear was worthless (on the street.)


To reduce the cam a slight amount, I plan on using Rhoads Vmax lifters. It won't be exactly a XE274 because I have to reduce the lift to use the 1.6 roller rockers that I have purchased.

Some of the guys here almost scoff at a 268 cam because the 1968 four speed 340 cam was larger. This car won't see a track for a long time. On the other hand, it is a long drive out of town to anywhere (big city is jacksonville, florida). The car shows are even further. If the 2.94 doesn't satisfy, I will change it and update the results to you and others here. I am very interested in your input, but I will try it out now before I commit funds in that direction. After the wife quit working to watch our baby, I lost over 20K in our budget and added baby stuff to the bills.

I would be happy to hear any other input.
 
It's your choice but I have ran the XE274 cam in a 360 and it was no torque monster so I totally agree with grumpus that a 2.94 gear isn't enough gear, unless your running super short tires (24"-25" max). You stated your running Vmax lifters to reduce the lift because your running 1.6 rockers? I hope that isn't because the cam lift with 1.6 rockers is more than the heads want because the Vmax lifters pump up at higher rpm and restores all the duration and lift. As mentioned Vmax lifters bleed off some duration and lift at low speeds but did you know that running 1.6 rockers gives you the same effect as running a cam that has 4 degrees more duration at .050" lift and adds about .025" lift? I have measured and verified that, not just hearsay. The Vmax lifters will help with low speed torque output but by running 1.6 rockers you defeated their purpose IMO. You say the car won't see any track time for a long time so why not run the 268 cam instead? With the 1.6 rockers it'll act nearly the same as a 274 with 1.5 rockers.

Also keep in mind that first gear isn't the only gear you have to take into account. 4th gear OD combined with 2.94 gears will make for a very low rpm hwy gear, which I realize is good if you cruise the interstate at 80 mph but it may be more than the cam will like and it will kick and buck like a Missouri mule in OD unless your running at least 70 mph. Again, the rear tire size has some effect on the final drive ratio.

Whoever says the 68 340 4spd. cam is bigger than the XE268 cam apparently hasn't compared ALL THE CAM SPECS OF BOTH CAMS. The total duration of the 68 4 spd cam was a little more than the XE268 but total duration means very little compared to duration at .050", which is the same as the XE268 and lift which was about .020" less on the 4spd cam. The biggest mistake I see a lot of guys make on street cars is to over cam their engine. Then they fight tooth and nail trying to figure out why it won't make any low end torque. IMO your always much better off going one size smaller on the cam than one size too big

Now back to your original question, the clutches in the diff should be fine as long as their not worn out already, you said it was ran real hard so it's hard to predict what condition it's in. I'd also be worried about the nearly 40 year old seals. I'd bet their dried out hard as a rock and it'll leak oil when in use. Synthetic lubricant's also seem to find every place to leak from they can. Personally I wouldn't install a rearend of such questionable condition because I hate to R&R them. At a minimum I'd do a complete mechanical survey to see what it's condition really is
 
Gonna be easier to review what condition the rear is in while it is still out and on the bench! I would dig a little deeper into I before installing it if it were me!! Just a thought!! Geof
 
I would pop the carrier out and throw a new set of clutches in it put that is just my ADD kicking in.

Honestly sounds like you funds are low, if the fluid was clean and the axle splines do not appear to have any twist in the splines I would put it together.

Also living in FL it has to be flat, so the gears should be nice with the od.
I ran a od with 3.23 here in the hills in WV in a duster and it really sucked, just not enough in high gear to pull the steeper hills, always down shifting to third.
 
Thank you gentlemen for all of your advice!!!


In my heavier Road Runner, I felt that 1st gear was worthless (on the street.) <-{This is a aftermarket cammed 340/833/3.55 car} This is coming from a guy that has been driving underpowered vehicles his entire life on the street.
Two 1991 civic's (1.5liter 2K lb cars), a 267 powered 1980 Impala (maybe 60 hp+1XXftlb torque-4K lbs), a tiny subaru loyale with cheese 1.8-2K lbs, and the wife's 1.8 turbo jetta.


To reduce the cam a slight amount, I plan on using Rhoads Vmax lifters.

You stated your running Vmax lifters to reduce the lift because your running 1.6 rockers?
Well I was hoping the Vmax would help the bottom end of the 274 cam. I was hoping the 1.6 rockers would help all around. I was not clear on that.

It won't be exactly a XE274 because I have to reduce the lift to use the 1.6 roller rockers that I have purchased.
I do not understand-have not checked to see if I can utilize my 1.6 rockers with the lift of the 'XE274' camshaft-I don't know anything about springs, shims, valve seat setup, etc. in that regard yet.

I will be looking for 3.55 gears, sure grip clutches/rebuild kit, maybe an axle rebuild kit and seals then.

If you guys strongly recommend a 268 cam, then that is what I'll buy. I was basing it off of other statements here along the lines of a "baseline muscle car cam."

I wanted this car to be more aggressive (but comfortable) car than my road runner, but am concerned about always being able to afford gas. I am spoiled with 37-40+ mpg daily driving and driving accross country for parts and cars in my other cheap vehicles.

I was also afraid that a XE274 with a 3.73 gear would brake my cast iron Overdrive 833.

the web has these vehicles at around 3500 pounds and I have been loading up insulation, truck bedliner, rubber coat, etc. making it even heavier...

I would greatly appreciate any advice on where to get the sure-grip clutch rebuild stuff cheapest and any other advice. Thanks everyone, even grumpuscreature!
 
I'm sure your 2.94 will be much better than the 2.45s I was dealing with in the 75 Dart. I would just idle at 55 in O.D. I went with the 3.55s and it still cruises at 70 plus without screaming.
 
4sp OD is basically a 3sp with an OD..duh, that didnt come out right. I mean 3rd gear is the same as 4th in a standard 4sp, 1:1 and with a 2.93 rear, thats hauling *** up in the xe274 power band. 4th would be circle track stuff! Im wondering if you would be happy going the other direction, an RV grind/stump puller. With that high OD and low numerical rear, you would be cruising right in the torque band and still have a super first gear launch.
 
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