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View Full Version : 555 questions : Rebuild, Strengthening, and Lower FD



glhs399
05-13-2006, 01:36 PM
I have finally decided to not to just use the 525 for my Omni rally car and to get a 555. What needs to be done to make this thing bullet proof? I know you can add the molly endplate, but I'm not sure what else to do to this thing. Also is there any other FD I can put in it other than 3:85.1? I need a lower top speed (I only will see probably 115 MPH at max, if have the balls :o !)
Thanks in advance,
D.Folsom
Hillsboro Oregon
85 GLHT Rally Car
86 GLHS #399

tryingbe
05-15-2006, 01:11 AM
Negative on the 3.85... unless you buy a transmission from Gary D. He has a super low geared A523 or something.

You can add LSD.

BadAssPerformance
05-15-2006, 01:28 AM
3.85:1 is as short of a FDR as you can make an A-555 with stock gears, but if you were looking for 115mph max, then that trans gives you ~114mph at 6000 rpm on 23" tires (205-50-15) in 4th gear. Which is good because 5th gear is not overdriven but also weaker due to trans design

They also made A520's with 3.85:1 diff gears that were overall a little shorter based on the individual gears. That combo will give you 115 mph in 4th at 6700 rpm on the same tires.

Check out Frank's gearing calculator:

http://www.squirrelpf.com/gearingcalc/

As far as strength and performance, in addition to the CM bearing plate, you can also get a Quaife or OBX LSD for it. Or if you are going dirt only rally, I might have an interesting alternative idea involving a welder ;)

glhs399
05-24-2006, 05:16 PM
Looks like I'm stuck with the 3.85:1. I do plan on welding up the diff :eyebrows:, but I'm still having a hard time deciding if I should buy a 520 or a 555 or just use my 525. I have all the parts needed to beef up the 525 (endplate, girdle, ect.) With the current build of the engine I should be around 200 HP. Think the 525 will handle it? Also with the 555 and the 520 you get larger axles right?

Still not sure what to do about my tranny!!:mad:
D.Folsom
Hillsboro, OR
85 GLHT Rally Car
86 GLHS #399
05 SRT-4 (For Sale)

cordes
05-24-2006, 05:23 PM
At 200HP, I would just run the 525. I don't think that you will be able to shock the trans enough in that aplication with that HP to really break it.

MiniMopar
05-24-2006, 05:45 PM
+1. An A525 with those upgrades should hold up OK pulling an L-body.

BadAssPerformance
05-24-2006, 08:33 PM
As long as you dont grind the gears... ;)

MiniMopar
05-24-2006, 08:44 PM
If I remember my mom's 86 LeBaron correctly, you have to drive it like a truck...double clutch it. LOL. It ground anyway...

BadAssPerformance
05-24-2006, 09:10 PM
lol... or just make sure the clutch is fully engaged every time and the syncros, shift fork pads, etc are all fresh so the gears work right :thumb:

glhs399
05-25-2006, 12:05 PM
Thanks guys! :thumb: I'll just stick with the 525 for now and rebuild it. Is there a place where I can buy a rebuild kit for this tranny? Also are there any little secrets you can do to these trannys to make them last or improve the shift quality/speed? I plan on adding a drain plug but other than that I'm clueless!

Thanks, D.Folsom
85 GLHT Rally Car
86 GLHS #399
05 SRT-4 (For Sale)