to have the car dyno-tuned for the 500 miles, you know, that break-in period that everyone says is for the rear anyway, just as if the whole car was brand new or just drive over to the shop and have the car dyno-tuned 15 miles away that same day? Its an A4 automatic and I know by waiting the speedo will be off but is that the only thing that will be off and do you think it will be ok to drive to break-in the new rear for a 500 mile period and if I do will it affect any other part of the car by waiting or it really doesn't matter? I don't mind waiting if that is the correct thing to do?
Appreciate all opinions on this one; I'm running out of time.

Thanks...
ps someday when I finally learn how to put pics in these threads, well, seeing is believing.

 

The shift points will be off until you have the TCM tuned. You can do that without putting the car on a dyno and abusing the new gears. See if your tuner will be willing to make you a deal, tuning the TCM now, and then dynotuning the whole package after the gears break in properly.

 

Shopdog:

I spoke with both the tuner earlier today and the service manager at the local chevy dealer who both said that if I drive "normally", kind of like an "old lady" for about 200-300 miles, that it shouldn't "hurt" the gears.
I am not trying to put down what you're saying to do, but I wanted to run this by you for your opinion (again). Could they both be wrong? I really don't know and just want to do what's best. Someone else said I should drive the car in circles to get that new gear fluid additive moving around thruout and around the rear gears; it seems like everyone has their own opinion and sometimes it really muddies the waters.
I'm still interested in what you think, in light of the additional info...
ANYONE ELSE FEEL FREE TO JOIN IN PLEASE...thanks.

 

Having changed the gears in my C5, I can tell you that the car may not, and probably will not, shift right at all, and can and probalby will set a code if it is not programmed immediately following the gear swap.

The shift points will have to be set properly before you can even drive it any appreciable distance. Otherwise look for hard shifts, which get harder, increased line pressures and possible transmission damage.

I doubt, unless you are going from say, 3:15s to 3:42s, which is not that much of a difference, that you will even get 15 miles without it acting up. I couldn't. But some say that you can if you keep the gear selector in 3 as opposed to D. Some have been able to go for a few hundred miles this way before throwing the P1870 code.

I wouldn't dream of doing a gear swap in an automatic C5 or C6 without programming in my shift points right away.

Bottom line, get the shift points set up properly immediately following the gear swap if you can. Baby it for the 500 miles, then take it back to have the dyno tuning done.

Good luck.

 

Heres the deal with gears, heat cycle them. Gears need to be heat cycled, drive for about 20min smooth not tearing *** and then let it cool down ALL THE WAY. Do this a few times and your straight

Ryan
Revxtreme

 

Thanks, Ryan-got it!

See you soon and I'll call for that AM aptmt as we discussed, probably the week after next; if not then, then NLT the week after that.
Thanks for taking the time with me at your shop last week to explain everything that is involved with the HP Tuners program and dyno-ing the car.
Sal

 

What gears do you have and what are you going to?

I went from 2:73 to 3:42 and never had any codes set, the car drove completly normal at all times except at wide open throttle. At WOT it would not shift, would hit the rev limiter first. It would shift fine when I left off the pedal. I drove it like this for a week before I could make it into the tuner for the tune, not a big deal.

 

Cucchiara,

I'm quite sure Purple Heart would appreciate this pertinent info. I believe this is exactly what he is looking for.

 

Cucchiare, that is exactly what I was looking for and just what I thought it would be like. Tell me, after the install, did you feel the difference once the car was set up correctly, by the SOP feel? Or was there very little difference to "feel"? Did you actually race another car and see the difference? Where did you get your differential from, just out of couriosity? Who installed for you and how much did you pay(if you feel this is being too nosy, you don't have to answer the cost to install question)? Was it worth it, after all is said and done?
Thanks,

Sal

 

I thought this only applied to the engine oil to change at the first break in 1,000 miles to remove all the metal shavings.
So this applies also to rear end differentials and automatic transmissions?

 

All that I mentioned was done to my C5. So far I have done the same mods plus headers on my C6 but no gears yet. I was trying to find a take out rear diff from a 6 speed car with the 3:42 ratio to install in my 2:73 geared C6. The only options that I know of now are a brand new GM diff priced at $2k from Beans or remove your diff and have it built with whatever gears you want from DTE with prices starting at $1800 plus shipping. I have found a couple of 3:15 rear diffs from 05's in the $600 range but not sure if it will be worth the gain for the cash and labor. I do all my own labor, installed my stall and headers etc...Most shops charge $300-$500 to R&R the diff, its actually pretty damn easy in these cars. Iam not sure what Iam going to do with my 2:73's now, Iam running 11.90's with these few mods.
Matt

Edit to add the 3:42 made a huge difference in the way the car felt, will love to do it to the C6 but not for $2k when Iam already doing 11's. When I did the C5 I bought a brand new zo6 rear diff from Fred Beans for $900, sure wish the C6 diff was in this price range.

 

No way....I personally changed the tranny fluid when I did the stall, replaced it with full synthetic tranny fluid. I probably wont touch the rear end fluid, since I plan some kind of gear change before the normal service interval.

 

"No way" do you mean you wouldn't change the rear end fluid and transmission after they are broken in like your engine oil to remove metal shavings?
fluid to the Synthetic tranny fluid. Is yours an A-4 automatic?

 

Unless Im mistaken the C5/C6 Speedo Sensor is after the ring and pinion (ie doesnt effect speedo). However the PCM/TCM does shift by speed instead of rpm which will result in a higher rpm shift point and possible shift problems.

Gene

 

Probably, but I'm told that if you drive the car easy, you shouldn't have any problems. However, doesn't that basically defeat the perpose of having a Corvette, not jus to cruise in style but to kick your opponent's a$$ in a race? I probably will drive "old lady" like for about 150-200 miles then have it dyno'd the week after next. God, I can't wait...

 

I don't know if you have an auto trans A-4 or A-6, or manual but do you notice any differences when you switched to the synthetic tranny fluid over the Dexron III (H)?

 

I just changed my gears from 3:15 in my auto to 3"73. Jeff Creech at Carolina Auto Masters said that they need to be heat cycled before WOT. He set my shift points based on best guess but wanted me to drive the car a bit bofore he put it on the dyno for a good tune. Drive it 20 - 30 min. at varying speed but no hard throttle or WOT let cool down for about 1 hour. Drive 20 -30 min again with same cycle, then let cool down completely. Drive it again for 100 - 200 miles with easy throttle and no WOT. after that, get a dyno tune and everything should be fine.

 

We are talking pre-tune. As mentioned, if you go WOT, you will probably hit the rev limiter before the MPH based shift points. If you can't get it adjusted properly, you should wait on the hard driving. It defeats the purpose of modding to destroy your tranny, just because you're impatient.

 

Hold on a minute here, just because I said "God, I can't wait" it is a figure of speech. I can wait, I have no problem waiting and I will wait till it's properly "broken in". Just to be clear on that. Maybe my choice of words came across with a different intent.
Im not saying I know it all cause I don't but as a matter of fact, anyone who ever buys a car from me with get one that has been PROPERLY maintained for as long as I have owned it, never abused or neglected and always treated with respect and babied, except to the point of the occasional race once in a blue moon. I buy my fun cars and show them, keep them maticulously maintained, spotless including the entire undercarraige, and never drive them in the rain-if I get caught at a show thats one thing; and I never put the car in the Garage dirty! That's so I can always cover it up.
Nope, with this car, the Calloway Honker, the Melrose headers, Random Hi-flo cats with x-pipe and the stock mufflers that I have had jet Hot Coated to match the Melrose headers and now the 3:42 with my A4 is all mainly for bragging rights and show. Thats all. Just knowing the car is killer at car shows and I'll show against any car around and knowing that it will beat alot of other cars on the road-AND I'd even bet some of the A6's out there too is all I need. Yep, just mainly for showing and bragging rights, that's all.
Have a nice day.