More info on differential gears

Topic: More info on differential gears (Read 3150 times) previous topic - next topic

More info on differential gears

Reply #15 – January 12, 2006, 08:36:01 PM

My axles and housing never broke either. Everytime it broke it was because one or both of the spider gears grenaded. LITERALY. there was so much carnage the last time that I even split BOTH the bearing caps into 3 peices each. Never did find all the peices to those gears either.

Trust me. Take this thread as a warning my friends. the stock 7.5" WILL NOT handle alot of abuse for long. I know. I will post some pics later (if I can find them) of one of the diffs.

More info on differential gears

Reply #16 – January 14, 2006, 04:07:17 AM

Quote from: 1WLD BRD

My axles and housing never broke either. Everytime it broke it was because one or both of the spider gears grenaded. LITERALY. there was so much carnage the last time that I even split BOTH the bearing caps into 3 peices each. Never did find all the peices to those gears either.

Trust me. Take this thread as a warning my friends. the stock 7.5" WILL NOT handle alot of abuse for long. I know. I will post some pics later (if I can find them) of one of the diffs.

agreed

the axles will take you deep into the 6's in the 1/8 mile they are the same as the 8.8.

the weak point of the 7.5 is the ring gear/spider and the bearing cap area.as stated above

the are good for about 200 FLYWHEEL h/p

ive had alot of bad experiance with them including broken carrier on a STOCK 86 gt i had .

if you dont plan on abusing the car or using sticky tires and drag racing it may last you for a while.

More info on differential gears

Reply #17 – January 14, 2006, 08:05:50 PM

My 1988 Tbird 5.0 came with 2.73s, and they were the only V8 gears mentioned in the owners manual section on towing. I bought an 88 turbo coup parts car 5speed and the gears in it are 3.73s.As soon as I get my garage( I'm building) done I'm gonna swap the rearend disc brakes & all(can't wait). I did find a pretty good selection of rearends available through junk yards on line, average price $300. But If you can get a whole car you'll have the proportioning valve, rear calipers, etc, too.

More info on differential gears

Reply #18 – January 14, 2006, 11:44:03 PM

I agree with 1wld brd. It is pointless to build that 7.5. You will have to buy new axles to handle power and then gears. Just find a 8.8 out of a thunderbird turbo coupe. They came stock with 3.73's if the car was an automatic and 3.55's if it was a manual. Not only do you get the gears it is also a posi loc, and rear discs. ya its more work but its better to that kind of job right the first time around rather.

More info on differential gears

Reply #19 – January 15, 2006, 12:55:36 AM

Hmm. I've scanned online for the complete rear end, they're not that plentiful in Canada. None even close to my area and between the shipping costs and possibly duties that's a considerable cost. I could always keep an eye to Pickn' pull, they'd probably be cheaper but I'm not sure I've ever seen a turbo coupe there. Just about every Tbird I've seen sped was a 3.8. If I were to guess I'd say the turbos had a relatively short life, followed by the 3.8s and sometime soon probably the 5.0 birds will show up there in greater numbers. But I digress, I guess I've got some thinking to do.

More info on differential gears

Reply #20 – January 15, 2006, 11:46:32 AM

Well, others may have had problems with a 7.5, but I put a set of gears in a 2000 V6 Mustang, built it with a stock Ford Trak-Loc, and a set of 3.73s, no breaking. By the way, that car ran low 13s on a warm night, and high 12s on a cold night due to a supercharger. Now, I am not good with math, but to make a 3500 pound car scat down a racetrack that fast, sure takes a heck of a lot more than 200 flywheel horsepower.

More info on differential gears

Reply #21 – January 15, 2006, 12:56:03 PM

Ok. A 2000 7.5" has WAY less wear and tear on it and has not seen the mileage that one from say an '85 has. Just keep your fingers crossed. Eventually it will give out.

Plus if it was centrifigally SCed it wont give that instant hit of torque that even a stock 5.0L can give it. The power doesn't come on as aggresive with a 3.8L

More info on differential gears

Reply #22 – January 15, 2006, 01:55:56 PM

Quote from: slowfoxbird

Well, others may have had problems with a 7.5, but I put a set of gears in a 2000 V6 Mustang, built it with a stock Ford Trak-Loc, and a set of 3.73s, no breaking. By the way, that car ran low 13s on a warm night, and high 12s on a cold night due to a supercharger. Now, I am not good with math, but to make a 3500 pound car scat down a racetrack that fast, sure takes a heck of a lot more than 200 flywheel horsepower.

Slow fox what was your 60 foot time with a 12 second et?

Quote from: 1WLD BRD

Ok. A 2000 7.5" has WAY less wear and tear on it and has not seen the mileage that one from say an '85 has. Just keep your fingers crossed. Eventually it will give out.

Plus if it was centrifigally SCed it wont give that instant hit of torque that even a stock 5.0L can give it. The power doesn't come on as aggresive with a 3.8L

I'm betting he did have as much torque down low as a stock 5.0. Also if mr weirdo is going to be changing gears he will be replacing worn components. Rearends break because of slop in the gears. He will be taking care of that slop hopfully.

More info on differential gears

Reply #23 – January 15, 2006, 07:19:06 PM

Not my times, that was a rear end that I built for someone else, but still, he was cutting 2.0s and 1.9s on drag radials. CougarSE, you are correct about things breaking from slop. Ford calls for .008-.013 inches of backlash on a ring and pinion set, but when I build them for performance I make sure they are .008-.010 inches of backlash.

More info on differential gears

Reply #24 – January 15, 2006, 07:48:39 PM

A newer 7.5" will live with 1.9-2.0 sixtys IF they are in good condition. Older ones with wear are gonna pop just as wildbird says... And if the car will pull 1.7-1.8 60s you better have a 8.8".

More info on differential gears

Reply #25 – January 15, 2006, 10:23:04 PM

Hey guys the 7.5 and the 8.8 has the same axels. The diff's are the weak link. I've seen 8.8 trac-loks blow with 4.6 G.T. with spray on them. The slicks or drag radials will take there toll on any stock diff with 275RWHP or better.
Stick cars harder on the rears.
My car has a 1.60 60 ft time on drag radials, Currently has stock axels and diff. I've got new axels on my list of needed parts. Along with the Exploer 31 spline trac-lok