7 1/4 questions

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vwmoparguy

vwmoparguy

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What typically fails when using a 7 1/4 rear end with a fairly stout small block on the street? I know it's not the desired rear end to use and all I hear is "don't use it". But.... why?

I see they make a new diff pin for it. Is this a problem area?

I was also wondering if a limited slip, trac lock,etc, diff from other vehicles (like a Jeep) will work in the Dodge 7 1/4 rear end? Some Jeeps use a Dana 35 which is a 7 1/4.
 
The lack of gear oil. Seen a bunch that failed and were empty.
 
Would you put a 55 Bug transaxle in a 911 Turbo??
' bout the same as putting a 7.25 behind a potent small block.

It just ain't made for it.
 
Thanks Yellowdart dave and crackedback. The only reasonable answers.

I see there are people on this forum who just like to pad there post count.

"1968FormulaS340 I would like to post in this thread but Im lost in the bewbies."

"Snake At first I did not even read his reply"

Then why bother
 
I would just run what you have. I've run them behind a Commando 273, and a mild 4 barrel 318 in a 73 Dart. Both were sure-grips but held up and did not fail. Then keep you eyes open for something stronger. I do not know of any sure-grip that will fit other than OEM.
 
I find Crackedback's signature .gif a bit distracting, too. (Thanks)

My 7¼ failure occurred at the bearing on the driver's side. It was installed behind a 225/904 combination. Parts for fixing this are still available.

A possible contributing factor was water in the diff lube (milky color). Not sure how water got in there as there is no sign a trailer hitch for boat towing can be found on the car. We do have flash floods and occasional deep water over roads. A PO may have tried to ford deep water.

I had a 273 HP / 904 '66 Dart GT that had an open 7¼ behind it. I experienced no problems with it.
 
My drivers side axle bearing was replaced and my car has only 64.000 mile on it, BUT!!
I think it's because it has a standard shift trans in front of the 7 1/4, I had a 70 318 barracuda that had a 7 1/4 in it with an automatic and I never had a problem with it.
Yes, If you can find a sure grip unit for it it will be stronger from what I was told and read.
The 7 1/4 rear axle bearings are a sealed bearing and has a seal that keeps the gear oil away from the bearing. As you can see there is a seal in the first picture that hold the gear grease/oil in the housing with an axle seal.

Pictures, The last picture is after a friend with a press finished me up.
 

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vwmoparguy said:
Thanks Yellowdart dave and crackedback. The only reasonable answers.

I see there are people on this forum who just like to pad there post count.

"1968FormulaS340 I would like to post in this thread but Im lost in the bewbies."

"Snake At first I did not even read his reply"

Then why bother
Click to expand...

Because without humor we are nothing. Just roll with it.

As for 7.25 failures, probably the first thing to break will be the spider and/or side gears. Don't waste any money on it, save your money for something better after the 7.25 breaks.
 
Thanks guys, that's the info I'm asking for. I may be a newbie but I read as many posts as I can related to the info I'm seeking.
 
Guitar Jones said:
Because without humor we are nothing. Just roll with it.

As for 7.25 failures, probably the first thing to break will be the spider and/or side gears. Don't waste any money on it, save your money for something better after the 7.25 breaks.
Click to expand...



I can roll with humor like the next guy. I guess my mood at the time didn't see it as humor. Thanks guys
 
I appologize, I just figured a free bump to the top of the list would keep your question exposed to the most experienced here. Sorry

I didnt have a good anwser for you re: What breaks the most often. But here is the reasons I got rid of my 7.25;

-The bearings were shot and the gears worn and was howling badly
-I'm planning on an engine swap from 225 to 360 (318 in the intrim)
-I read about all the failures others had experienced

Again sorry about my earlier, non informative post
 
I had one in a 73 duster that I abused for 9 years behind a 4-speed, 318, the rear never broke but it was a 3.23 open carrier.
Maybe I was lucky but the car only had 70,000 miles on it when I bought it.
I just changed the gear oil in it every so often.

I also broke a 8 3/4 in my first car, spiders went ?????
 
Guitar Jones said:
Because without humor we are nothing. Just roll with it.

As for 7.25 failures, probably the first thing to break will be the spider and/or side gears. Don't waste any money on it, save your money for something better after the 7.25 breaks.
Click to expand...

yup spider/side gears, that is why they last longer with a sure grip, it spreads the load to both side gears more evenly, and the spider gears are not spinning around frantically while one wheel spins, after that the next weak spot is the small ring and tiny little pinion gear

(sorry for the pointless post, just trying to get that gift card)
 
Thanks for more good info guys.

I have been doing internet messageboards and forums pretty much since they started. I'm not new to forum policies, trends, and etiquette. I honestly took those few posts negatively, and if they were meant to be funny or positive (?) I apologize. I like to joke and have fun like everyone.

Sorry if I ruffled anyones feathers.

I am not a newbie to cars. Just to this site. If I ask a question, it's because I don't know the answer and didn't find it in a search. I love this site. Maybe someday I'll get my Walmart gift card, haha.
 
vwmoparguy said:
Thanks for more good info guys.

I have been doing internet messageboards and forums pretty much since they started. I'm not new to forum policies, trends, and etiquette. I honestly took those few posts negatively, and if they were meant to be funny or positive (?) I apologize. I like to joke and have fun like everyone.

Sorry if I ruffled anyones feathers.

I am not a newbie to cars. Just to this site. If I ask a question, it's because I don't know the answer and didn't find it in a search. I love this site. Maybe someday I'll get my Walmart gift card, haha.
Click to expand...


loosen up, hang out, and have fun! you'll do fine
we aint always to civilized on here, a lot of goofing around

as for the 2 bit posts, they actually serve a purpose, they keep your question from getting buried so deep that no one sees it, this way it stays on top until someone comes along with an answer

you can kind of think of this place as 19,107 people sitting around a small corner bar talking about cars on 127,207 different subjects


oh yea it's usually hole shots and burnouts (or any really hard launch) that causes them to break, if you drive "normal" they will last
 
Dad had 2 that failed spider gears and both were open and he had 1 shear the ring gear bolts off the ring gear and that was a sure-grip. They were in a 65 Formula S with 4 speed and fenderwell headers.
 
I epically destroyed the 7 1/4 rear end in my dart. was taking a nice drive and also hauling ***:twisted: and boom! Pulled over, took off the cover and sheard that housing that holds the spyder gears and my dart has a stock 1988 318 with a 5speed in it.
 
I replaced my /6 in my 72 Duster with a .40 over 360 ,still has the 7 1/4 but I havent done burnouts or anything crazy or race.I drive it pretty casually and its still holding up.Now I know if I statrt abusing it ,it will go boom but normal driving should be ok =)
 
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