time benefit from 3.07 - 3.45?

[rrubel]

Don't forget, Mic, I'm planning to attempt the work myself. I'd never do it if I had to pay, but a rear diff seems a lot simpler than, say, a clutch.

If I can get three tenths out of $85 in parts plus some time, that's worth it... Even if I just drop a couple 10ths off my 0-60, that'd be even more worth it.

And if I change my mind, there's always eBay .

[RICHR]

 

[Mad-Mic]

Rich i would do the clutch with no problems. the diff is a different story! you have to make sure it's shimmed up right and it's a PITA. that is one thing that is not for the average guy to do. if it's out of line by an 1/8 inch you'll be spending more money than 85 bucks.

i know you'll check into it but this is something i would not attempt to do.

clutches? bring them on!

 

[kingman]

???????????????????????????????

Let's get this straight, if l have 3.07 gears in my auto LT1 (96) and change my rack and pinion to a 3.73 l'm ok.

But if l change my torque converter to say 2100-2400, then l will need a tranny cooler!

Then will l get the best bang for a buck to just change my gears and forget the torque converter?

I do not drag my vette and just like the pull when l start off.

Thanks

Alan

 

[vader86]

I'm sorry but it would hurt your ET in an L98 with TPI on top. You would be out of your powerband in 3rd gear by the end of the 1/4, and we all know that shifting to 4th just kills ET. I know this because Ive seen L98 guys with lower gearing and it did hurt their ETs.

Although with a SR, like i said, it wouldnt make much difference.

A tranny cooler is a great idea for ANY 700r4/4L60, doesnt matter what you do to it. However, running a higher stall TC will increase transmission temperatures some, and a cooler would be more beneficial here.

You can do either one, if you dont drag it, then you dont need to do both. Doesnt really matter, both will make you quicker by about the same amount.

 

[muddywaters]

Rearends

Hi, 30 thousands are way off Mad-Mic.

 

[muddywaters]

Clutch

And by the way, in rare cases, clutches require shimming also.

 

[rrubel]

Vader, I usually need to shift to 4th anyway by the end of the 1/4. 4+3, maybe that makes a difference, but I'm at 5K in 3rd and fading fast a couple hundred yards from the end.

Mic, I was looking through the Haynes manual on removing the rear diff and such; it doesn't say anything about shims. Are they internal to the diff? Yes, I know I need to read my shop manual instead... don't say it!

Kingman - that's RING and pinion, not RACK and pinion . Careful, or you'll wind up with the world's only 4-wheel steering Corvette! The pinion, btw, is the shaft with a gear on the end. In a rack and pinion steering system, the pinion rotates and moves the rack (a flattened gear, really) from side to side. In the rear end, the pinion is attached to the driveshaft and it turns the ring gear, which in turn moves the halfshafts via the differential.

[RICHR]

 

[Mad-Mic]

Re: Rearends

Hi, 30 thousands are way off Mad-Mic.

what do you mean? the tolerances in a rear has to be very close with no slop. if you get alot of slop you'll hear a hard whine then eventually it'll go bang.

clutches on the other hand i've changed out a many T-5 clutches and a few others in imports and never had a problem. most clutches don't have shims at all just a clutch shim tool which is different than shims themselves.

i am not a pro mechanic but have been around race cars all my life and worked on many cars.

 

[muddywaters]

Rearends

Hi, Mad-mac, 6to8 thousanths is in the ball park for ring to pinion clearance. Too tight, acceleration whine. Too loose deceleration whine. There also the issue of pinion depth and carried bearing pre-load. Some types do it with shims, others are adjustable and like Mad-Mic said, all are a PITA. 1/8 inch is .125 thousanths so you can't see it with the naked eye, special tools are needed . I've never heard of a clutch shim tool, pilot tool , yes. I've done clutches and diffs. and I'm definetly no pro mechanic I just like to tinker with a shop manual at my side.

 

[Mad-Mic]

that might be what it's called. it's the tool that comes with the clutch to line up the clutch when installing. looks like a piece of plastic pipe with teeth on it.

can't remember the exact name for the life of me. i thought it was the clutch shim tool.

 

[muddywaters]

Pilot tool

Thats a clutch pilot tool, some are splined. Old timers would cut the main shaft off a junk tranny and use that as an alignment tool when they did't have a store bought type.