So I've got a 98 A4 coupe with 172K miles on it, mostly stock (has cold air intake, shorty headers, and aftermarket exhaust) with the 2.73. The car had 112K on it when I bought it just shy of 6 years ago. I do not drag and have never gone to a track event, but I do like to drive the car like a sports car is meant to be driven... if you catch my drift...

Shortly after I bought it the 4L60E crapped out and I had a GM reman put in at that time, so it has about 60k on it. The car has always had a bit of a whine that I had attributed to being the rear end, but recently it seems to be getting a good bit worse.

In anticipation of having to have the rear end rebuilt, I'm thinking of changing from the stock 2.73 to a 3.42 ring & pinion. I'm just starting to look into this project so still in the info gathering stage. I'm leaning toward buying an already built up unit on an exchange setup, but still looking into that. At this point, I do not plan to swap to a high stall TC.

So I know from reading that the sending unit for the speedo is in the reads the rear end output, so no speedo correction is needed. However, I do know that the PCM shift points must be reprogrammed or the trans won't shift properly. So my primary question is.... what's the best option for doing this-

1. buy software such as HP Tuners to change it myself (how user friendly is the software? do I have to be a tuning expert to use it? there are a few other PCM mods that I'd like to make that I believe can be done via this software so may be willing to invest the $. And I already have the laptop, so no additional cost there.

2. do a mail order PCM flash to fix the shift points- likely the cheapest option but all I'd get is the one-time service and may not be able to make some of the other changes I'd like to make.

3. buy a plug n play type of reprogrammer? I see that the hypertech max energy programmer says it can reprogram for a 3.42 gearing. I've used these type programmers on other vehicles in the past with no problems. but for the cost, would I be better off getting the tuning software?

I'm interested in your thoughts on the best reprogramming option, as well as any other thoughts you might like to share regarding the gear change if you have experience with doing this.

 

If you are not going to do your own engine tuning for mods like cam and heads then a handheld tuner is fine.
You can change the gear ratio and transmission shift points and firmness as well as adding some more advance and rev limit.
I added 3 degrees across the board and it made the throttle response
crisper and added more torque.
I have the latest Diablo Intuner I only used for a month before I decided to have an A&A Supercharger installed and dynotuned on my M6 so I don't need it any more.
It was returned to stock before the SC dynotune was done.
They are 385.00 new but I would sell mine for 250.00 or best offer but haven't gotten around to putting it up for sale yet.

 

Thanks for the opinion. I looked on the Diablo website but they don't list an option for any products to fit my car. When I select Chevrolet, the earliest year available is 99.

I don't have any plan of changing cam or heads so wouldn't have any use for HP Tuners for that purpose, for the foreseeable future anyway. But I've been told, and maybe read, that I can use the tuning software to increase the cut-off speed limiter from 2 mph to 255 so that next time the "column" lock monster rears its head I'm not stranded. He has been at bay for a couple of years, but did show up in a single, isolated incident once last week. I've also been told it's possible to remove the air pump test from the programming so I'll stop getting P0410 (as I have no intent of replacing the pump).

It was these sort of "extra" little things that had me leaning toward HP Tuners, given that it's not outrageously more expensive, as compared to a new hand-held. My biggest concern about going the turning software route is that it won't be straightforward and intuitive to use for the things I want to do with it. If anybody has experience with this aspect of HP Tuners, EFI Live, etc., please share your thoughts.

 

There are several tuners who do remote tuning, you buy the Autocal unit and they can send you programs to log performance data and then they can make the necessary adjustment to the PCM for performance, gear changes, trans shift points, etc.

The best performance changes can be made by this method because you are using real world data to make the change. If you are SC or nitrous, then a dyno tune would be necessary for optimal mapping.

 

If you just change the gear ratio find some one with a TechII (a wiling gm dealer) or shop they can adjust the pcm for that

 

I see you are in Huntsville also? I can take care of changing your ECM and transmission tune using HP Tuners. I've done a lot of Corvette and Camaro tunes along with several LSX conversions in this area. I get $150 to tune a car (covers the $100 HP Tuner license and a little for my time).

I've also done over 10 cam swaps and 8 or 9 clutch swaps on C5s among other heavy maintenance (Procharger install, etc), so I can help with your rear differential swap if you need it.
Clyde

edit - also wanted to add that if you just want to check out HP Tuners in order to determine if a purchase is right for you we can get together and go through the software and do a scan on your car.

 

I may take you up on that offer. If you want, shoot me a PM with your contact info.

I stopped by a local vette shop today to talk to them about the whine. But it's going to be first week of January before they can take a look at it.