Blackdog36

iTrader: (3)

Need some help finding a correct transmission core for my build.

I taking out the existing rear end, transmission and engine. Will be replacing these with an aftermarket 9" rear end, rebuilt transmission and dart SHP block in SBC Gen 1 configuration.

I will be rebuilding a transmission core with a kit from Probuilt to handle the new power. Since I am going through all this trouble, I would like to go with EFI's 24x LS1 coil pack conversion. EFI uses LS1 ECU which allows me to use a 4L60E transmission to easily change shift points versus a 700R4.

I found for sale near me a 4L60E out of 97 trans am with 5.7 LT1 engine. Would this transmission work with the LS1 ECU? I know that LS1's came out in 1998. I haven't seen too many 98-02 4L60E's for sale in my area. The ones that I see are way too pricey or partially rebuilt.

I did find some info on difference between 97-98 transmissions but doesn't seem to be an issue since I will need to get a torque converter anyways. 94-97 4L60E would bolt right up to a gen 1 SBC. 98-02 4L60E would required a flexplate spacer and new bolts to fit on a gen 1 SBC or you would need to get a LS1 torque converter. Not sure about the electronic differences though.

Thanks!

1ADan

iTrader: (4)

I'm finding the same info - will work, but will need the flexplate spacer if you're using the older sbc-style torque converter

Blackdog36

iTrader: (3)

Thanks Dan.

Did some more digging and found these links. They say it's not possible for LS1 ECU to control 4L60E from a LT1 engine. I think that I will look for a LS1 version of the 4L60E. Looks like they did start making LS1 4L60E's in 97. I will have to look into the tachometer control. I see mentions of a "dakota digital" box that would work ($$).

This post says no, electronics won't match
http://www.ls1tech.com/forums/automa...-ls1-swap.html

This post says electronics change in 96
http://www.theformulasource.com/foru...howtopic=14723

antoine

I think it will work if you use a 1997 4l60-e.

Blackdog36

iTrader: (3)

I was on EFI Connections website yesterday and saw something that got me thinking. They talked about how their 24x conversion is the only fix to replace optispark system on the LT1's. EFI must have come across this same question before. Why would somebody want to replace optispark if they also had to swap their 4L60E to a slightly newer one from a LS1 car? I'll give them a call soon and see what they have to say.

Blackdog36

iTrader: (3)

Have an update. Was able to speak with Mike at EFI Connections. Very helpful with my questions and knew a lot as he has done a similar modification.

Must use 96 or newer 4L60E to work with the LS1 ECU. LS1 transmissions will work but you need the flexplate adapters as mentioned above. Would also need a LS1 style torque converter. To hook up a 4L60E to a thirdgen dash, you cut wires from buffer box under dash and connect two wires attached to new harness from EFI. This will handle speedometer and cruise control from 4L60E transmission. No need for Dakota Digital converter box.

EFI has a few different ways of controlling your AC with LS1 ECU but sounds like it's not an issue. Just which way you want it controlled.

Here is the bigger kicker that I learned. I knew from their website that it would cost $700 for them to prepare a wiring harness for TPI cars. Mike told me that the later year thirdgens like my 92 have some harness differences than the early year TPI's (85-88?) that make preparing a harness a big pain for them. You have to supply EFI with your own TPI harness or a donor one for them to modify. On top of this it would cost another $450 for labor bringing harness total to $1,150. Doing a harness conversion for LS1 use with a later year TPI harness is a lot of work for them and is not something they always offer to do as it takes seven days to finish. It does not talk about this on their quote section of the webpage.

Even with the extra cost, I think that I will go with the 24x conversion. I'm planning a whole new drivetrain and this conversion would be helpful. Ease of tuning, change shift points with ECU, coil packs so no need for distributor and better spark efficiency.

Lastly, Mike said that when supplying a harness there are certain things they can't fix if it is already broken. For example Mike said that starter fuseable connection is typically bad and they don't fix that. Time to modify harness by EFI would take 10 to 12 weeks or longer.