7.5 Rear rebuild and gear swap

Topic: 7.5 Rear rebuild and gear swap (Read 6562 times) previous topic - next topic

7.5 Rear rebuild and gear swap

June 19, 2012, 03:36:31 AM

The last few months 7.5" rear end has been getting noisy. So I went ahead and ordered a new set of 3.45 gears to replace the current 3.55. When I opened the cover I was surprised to find a ford Trac Lok limited slip. I was expecting to find a gear locker because thats what I asked for years ago when I last had the rear end built. The gears were Richmond 3.55 like I requested.
The problem is that some of the ears are broken on the clutch plates. I want to rebuild my LSD carrier with some new clutches, but I cant find the parts anywhere:punchballs: Does anyone know where to get clutches for a 7.5" ford Trac lok?

This is the new gear set
http://www.jegs.com/i/JEGS+Performance+Products/555/60021K/10002/-1

7.5 Rear rebuild and gear swap

Reply #1 – June 19, 2012, 06:46:40 AM

Here you GO!!!

http://www.latemodelrestoration.com/item/YPK-F75-PC/79-04-Mustang-75-Trac-Lok-Clutch-Kit

7.5 Rear rebuild and gear swap

Reply #2 – June 19, 2012, 10:34:53 AM

Thats exactly what I need, but it says " out of stock".

7.5 Rear rebuild and gear swap

Reply #3 – June 19, 2012, 12:28:14 PM

http://www.ringpinion.com/DiffWizard.aspx

7.5 Rear rebuild and gear swap

Reply #4 – June 19, 2012, 01:59:48 PM

Ummmmm.... Never heard of a 3.55 gearset for a 7.5" rear before....

3.45 yes. Not 3.55...

7.5 Rear rebuild and gear swap

Reply #5 – June 19, 2012, 03:57:17 PM

Maybe they were 3.45, but I'm pretty sure I saw some 3.55 sets when i was shopping for these. I was just counting the rotations and it was about 3.5 turns of the pinion to one turn of the axle. Not the most accurate test. Anyway, I found my clutches today at the ford dealer right down the street. They had them in stock for $103 :)
Those little ears on the clutch discs are what were breaking off on the old clutches.

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7.5 Rear rebuild and gear swap

Reply #6 – June 19, 2012, 07:38:56 PM

As far as i know their is no 3.5 final in a 7.5 but who cares. Glad you got the parts you needed.

7.5 Rear rebuild and gear swap

Reply #7 – June 19, 2012, 08:08:23 PM

so your running the combo in your sig through a 7.5?

maybe i won't need to upgrade afterall :D

7.5 Rear rebuild and gear swap

Reply #8 – June 19, 2012, 09:57:40 PM

The 7.5 is no slouch. It can handle some good ponies if set up correctly

7.5 Rear rebuild and gear swap

Reply #9 – June 20, 2012, 01:08:15 AM

I do beat on this car pretty hard. With all the towing, racing, and drifting. I used to tow an 1800lb trailer regularly with 3 quads. I'm still waiting on my gears and bearings to come in. Tracking says tomorrow. Here's some more pics.
look at the bent, dislocated ears sticking out of the clutch pack. I bet that was my noise.

you can see the bent clutch ears wrapping around the side gear here.

some smoked disks

7.5 Rear rebuild and gear swap

Reply #10 – June 20, 2012, 05:59:03 AM

In all the years in this business i have never seen a posi unit burn clutches like that, I think it is time to stop DRIFTING. That unit shows TREMENDOUS FRICTION AND HEAT ISSUES. It tells me the unit is trying to do it's job of keeping power to both wheels and it CANT. If i may!!!! If you keep on DRIFTING i would suggest an OPEN REAR!!! Personally my view on drifting is that is is the DUMBEST THING I HAVE EVER SEEN ANYONE DO WITH AN AUTOMOBILE!!! Just me could be wrong!!!

7.5 Rear rebuild and gear swap

Reply #11 – June 20, 2012, 06:04:51 AM

7.5 Rear rebuild and gear swap

Reply #12 – June 20, 2012, 08:56:40 AM

Quote

If you keep on DRIFTING i would suggest an OPEN REAR!!!

I'm not a fan of drifting myself, but that would be a step in the wrong direction.... A lot of the drifters will step up to a spool....

7.5 Rear rebuild and gear swap

Reply #13 – June 20, 2012, 05:10:47 PM

Quote from: V8Demon;392836

I'm not a fan of drifting myself, but that would be a step in the wrong direction.... A lot of the drifters will step up to a spool....

Now that is something to catch my fancy. Lets put a spool in a street car. This is a street car we are talking about am i correct??? If it was just used for drifting a spool would be fine. But that posi unit is clearly destroyed i would say. Just me could be wrong again!!

7.5 Rear rebuild and gear swap

Reply #14 – June 20, 2012, 07:56:55 PM

I should point out that the clutch pack on the other side was still in great shape. I'm pretty shure the transmission shop that built my rear screwed it up when they assembled it. The unit should not be able to generate enough friction to bend those ears out of their pockets in the carrier.
I counted the teeth on the old gear set and divided to find out the old ratio was 4.10, not 3.55. The shop really didnt do anything I asked them to. So not hard to believe they would screw up on the assembly.
Tom, most drifters actually agree that drifting is the stupidest thing you can do with a car, but its so much fun that we just cant resist. Open diffs are no good because both wheels have to spin all the time and predictably for the car to slide consistantly.
I just finished re-assembling the carrier with the new clutches. I'll post some pictures later when I get home. One of my friends is hopefully gonna be stopping by to help my set up the ring and pinion tomorrow.