Transmission change needed...looking for input - Page 2 - Fuel Economy, Hypermiling, EcoModding News and Forum

Nevyn · 10-14-2009, 10:53 AM

That's approximately the direction I'm going to head in. I called Dave at Triple Edge Performance; he rebuilds 4T65's for a living. He said that the 4T60 isn't much different at all.

I'm figuring to rebuild the one that's in the car. As much as I'd like to pull one to rebuild instead of working on one live, in all reality there is little point. I'll take two or three days vacation from work, get all the parts and everything beforehand, and just pull it out and do it in our basement.

I'd love to put lower gears on it, but I don't know what it has now and there are limitations on what it can be changed to. I'll have to look all of that up before I start.

Christ · 10-14-2009, 03:20 PM

Well, that's a given, my friend. You ALWAYS measure twice, cut once. Once you've cut the board, it doesn't matter how many more times you cut it, it never gets any longer.

The same applies for everything else - you never just jump in, you do research to make sure you've got all the options covered.

Nevyn · 10-14-2009, 03:32 PM

From folks over on the 60degreeV6 boards it looks like I can drop from a PROBABLE existing ratio of 3.29:1 to a 2.93:1 just by changing two gears. It'll require some update flashing to the PCM to do so. If that can be done for free, then I'll be all over it.

Christ · 10-14-2009, 03:43 PM

The update flash won't be done for free, but you can do it for very cheap. If you have a test board and a PC, you can do it yourself. You have to power the PCM up while connected via serial/OBDII to your PC/Laptop, then flash it following the instructions of whatever free software you're using.

99LeCouch · 10-14-2009, 09:52 PM

Also, anybody with HP Tuners or a DHP PowrTuner can reflash the proper gearing into your computer. That GP of yours is pretty popular to mod, so there are likely a few guys around you who'd be happy to flash your computer for a few brewskis.

Do you have a 3.4 or 3.8 powered GP? And are you sure it's the 4T60 and not the 4T65? 1998 was when the H-bodies got the 4T65, and I heard 1997 was when the W-bodies received it.

Nevyn · 10-15-2009, 09:50 AM

It's a 3100 and I'm 95% certain its a 4T60-E. Depending on gear costs, I may not go there, but if the physical parts are cheap enough I just might swap 'em. I'll ask around on the 60degreeV6 boards when the time comes closer and see if there is anyone in nearby area that can adjust it for me.