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4L60E swap from TH350 questions


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I came into a free 4L60E as part of a trade for a 4wd unit I had laying around. I have an entire 94 powertrain with harness and ECU. Im debating how hard it would be to wire it up and run with it behind my carbed 5.7L.

 

I have a few concerns that need addressed.

I have experience going through transmissions and I dont trust the 4L60E but with all the updates Im sure I can spend the time to go through it and make it stout. Eventually Id like to go T56, but for now Id like to be able to drive the car to car meets or work  if need be.

Id like to keep my HEI and not use the distributor from the TBI engine(94 truck). The transmission is from an early truck as well(circa 92-93 need to nail down an exact date of production still). Just a guess but Id bet the 94 distributor is similar enough to the HEI output that I could figure out which signal to catch to run the TCU part of the ECU. Im up in the air about dumping my 650 Holley for the TBI still.

Im sure I can adapt over the TPS to my throttle linkage to run the TCU as well. Id delete the EGR function completely and not worry about things like the MIL. I dont beleive the O2 sensor is going to be needed either for this even if I ran the TBI(it would just be in open loop all the time).

 

Im sure someone on here has done something like this. Ive seen mention of folks here thinking about doing this a few times.

 

My main goal is to get the TC lockup for the freeway. I have already looked into getting a B&M Torque Thrust 2000 stall converter for it.

 

Are there any pitfalls Im overlooking? In either case Id likely start out without the TBI and run it like that for a while, which means, no Fuel pump, no EGR, no O2, and the older HEI(5pin) in place of the modern distributor. Once I get the transmission in and successfully going Id consider getting the TBI adapter and adapting the fuel system over..

 

These early GM ECU's are pretty easy to play with, but I dont have a tech II in possession and I dont have a complete picture of how its programmed exactly(which inputs control which outputs). I know that the load(MAP) sensor and TPS are needed for the TCU part and that the ECU and TCU are multiplexed in the same box and have a replaceable prom... beyond that is magic.

 

Ray

Edited by rayaapp2
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You Can get a standalone computor to run that trans.The problem with modern automatics is how there were integrated to work with the ecm/engine to work as a package.The valve body on these trans is nothing but a bank of solonoids.Unlike the old 700r4 that had a electric lock-up on the torque converter that could be wired up to a switch.The trans cannot be controlled by any old gm computor.If the car is used daily on the freeway you might get a return on the investment of wiring it up.If its just a sunday car and it isnt used on long trips I would stay with a th350.The guys that run the 4l60e usually are running some kind of ls motor and its all wired to the gm ecm.

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Those stand alone units are pretty spendy from what Ive seen. Im trying to keep this trans swap under $600.

Id rather spend big money on an LT1 T56.

The 4L60E I have has the matching ECU/TCU... It seems like its just a matter of wiring it up and fooling the ECU into thinking it still running TBI but with an HEI pickup. The TBI distributor looks like it uses a 5 or 7 pin HEI module in a smaller housing with different connectors... which is what Id like to confirm.

I dig some digging on google and there is a lot of half information out there regarding swaps like this. I believe it can be done and on the cheap, its just a matter of knowing what Im doing.

 

I found this last night:

http://www.s10forum.com/forum/f10/how-to-carb-swap-and-keep-the-4l60e-461481/

Edited by rayaapp2
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2/4 clutch pack... excessive clearance @ OE spec. Aftermarket/updated solution is thicker clutches! The clutches end up slipping and it wipes them out in short order and its gets worse when line pressure is higher. Im not a transmission guy(one who does transmissions for a living), but Ive replaced plenty of 4L60E's in my day as a tech and noted the failures.

 

I checked the date on this transmission and its a 4.3L 94 Medium Van... So unless its been gone through before I need to carefully measure everything out and install the updated clutch packs and band. And that is just the one failure point I know of. This transmission was pulled from a 92 K1500... converted to 2wd. So the history is really unknown. I didnt even realize the SBC and the 4.3 shared the same bell housings, unless the information I got regarding the tag is wrong. Thats a whole box of worms though. What's odd is that from what Ive read the 4.3L models should be missing some 'ears' and this one is not missing any bell housing ears that I see. So the information I pulled could be inaccurate.

Edited by rayaapp2
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Got my Holley TPS and Torque Thrust 2000 today. Dam Holley kit was missing the Sensor! Summit is sending me a new kit Monday and sending for the defective kit on Tue.

Got an updated rebuild kit for the 4L60E yesterday.

 

Think Ill have it in by Next Saturday!

Guess I need to order my  Autometer Sport Comp Electric Speedo 3989 if I want to see how fast I am going without the cable drive.

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1236309_10201282048506038_744913922_n.jp

 

 

Harness is ready, Trans is ready... A really simple swap.

There is more to this though than the link I posted. You must retain the DRAC unit from the donor vehicle.

 

TCU95GM_zpsb2da74f6.jpg

 

I did discover that the DRAC wiring was off by 2 wires on my unit, but I was able to determine what they were... So there may be some variation in colors.

Edited by rayaapp2
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I had to move my driveline loop as well.

 

I almost have this sorted out. I can at least drive it down the block and get to 4th gear. So far Ive had no luck getting it into overdrive. I suspect I need to adjust the TPS, check grounds, double check my wiring, and try again.

This transmission shifts a bit soggy from the old TH350. Looks like I will be investing in the corvette valve body and piston springs pending the TCC resolution.

Im pretty happy with the gearing so far. I installed new brakes, went through my rear wheel bearings, installed new ball joints, new front wheel bearings, and did the trans swap. That was a bit much at one time I think. I have an issue to sort with the new brakes(a vibration).

 

I also took the time to install my Autometer gauges(Sports Comps). Speedo, Oil, Temp, and Fuel level. Tach was already in there.

Edited by rayaapp2
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Alright,

 

Got my brakes sorted. Found I had connected the tech lead wrong. Fixed that. double checked my power and grounds, and set the tps. I have a working transmission. Shift points are good with me. The kick down takes a little longer than I like. If I drive around in 3rd its really similar to the TH350. I can tell first gear is taller, but the car is so light it eats it up.

 

I installed a B&M 2000 torque thrust converter. Its seems to be stalling a lot lower than 1900-2200 rpms though. Its engaging the wheels around 1400-1500rpms. Im wondering if a 2500 stall would have been better.

Edited by rayaapp2
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Im digging 2100 rpms at 70mph not 4500rpms.

 

I had a second issue with the Holley TPS. The sensor was bad. The first kit had no TPS sensor and the second was bad. Holley is sending me a replacement. For now Im using the OE GM sensor which works fine and has more adjustment than the Holley.

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