About 3 years ago I started building a 5.3LS as a learning project, without much plan for what I was going to put it in. About a year later I had the engine running on a stand and started looking for a vehicle to put it in. I found a pretty nice, rust free, 2002 BMW 330i with a dead transmission that I bought and went about doing the swap.

I decided to go with an automatic transmission as the car was originally automatic. The 4L60E mates to the 5.3LS naturally and uses the same PCM. This car is going to be a street cruiser so an automatic trans is a good match and I already have a manual transmission Miata in the fleet.

After learning about the reliability issues with the 4L60E I considered a 4L80E, but there is limited space in the transmission tunnel and that would have required cutting out the tunnel. The 4L60E already required that the tunnel be hammered in a few tight places.

I found a used 4L60E on Craigslist close to home for $500. The seller “claimed” that the trans had been freshly rebuilt and had been removed from an Astro van that was crushed by a fallen tree during a tornado. Dayton had just had a tornado so his story was believable. The trans certainly looked like it had just been gone through as the case was clean, the fluid was clean and it had a sticker on it from a local transmission builder. Other than the seller’s word, I didn’t have much to go on and was just hopeful I hadn’t just wasted $500.

A few moths go by and I mate the transmission up to the engine and notice that the bell housing is missing the top bolt hole. No problem, the consensus is missing one bolt is not an issue. It means the transmission was originally mated to a LT engine not an LS, (1996 – 1998, I believe) this would confirm that it could have come from an Astro van. Additionally, the torque converter needed an adaptor to mate it up to the flex plate and I think I needed a different flex plate but eventually I got if mated up properly to the engine.

A few more months and I installed the engine / trans combo into the car. I had to remove the PRNDL switch and install a shorter shift shaft from a 700R4, just like the way the 4L60E is set up for use in the Camaro. I used a Lokar neutral safety switch on the shifter wired back to the PCM. This tells the PCM whether the car is in Park / Neutral or Drive / Reverse. (Pin 34, Blue connector, white wire, completes circuit to ground in P and N)

First time I try to drive the car and transmission feels like it is slipping, easy fix this time, trans was low on fluid after the initial fill of the cooler. I also have a larger aluminum pan on the trans so that took more fluid to fill than expected.

Second drive and the car moves forward but is sluggish like it’s in 3rd gear, reverse felt great and no noises or anything weird from the transmission. Time to buy HP Tuners to confirm my suspicion that the transmission is in limp mode. After reading the tune file from the PCM, I see there are no transmission controls installed in the program and it has been set up for a manual. I did a segment swap with a 2002 Camaro file from the HP Tuners repository, making sure it was the exact same Operating System ID#. I used a Camaro file, thinking that a Camaro should be about the same weight as a 2002, 3 series BMW and thus the shift points etc. should be pretty close to what I need. The Camaro also comes with no PRNDL switch which matches my set up. I made sure the transmission was set up in the tune configured for a P/N switch and not the PRNDL switch.

Since getting HP Tuners I have been working with LSX Power Tuning out of Texas to get the engine to idle properly and do some base tuning to get me around the block. We are currently on tune #8 and the idle is good and the car starts right up.

This brings us up to recent history. A couple of weeks ago I attempted another drive with more transmission issues. This time, in Drive, under gentle acceleration the transmission immediately shifts from 1st to 2nd then 3rd and briefly 4th, till I came to a stop and backed up. The car was surging while backing up at idle speed but I think that was more tune related than transmission, but maybe not. So back into the garage.

I sent the data log off to my tuner in Texas and he says the early shifting is not in the tune and to check wiring. So last night I pulled the pan and using either VCM Scanner (HP Tuners) or my Power Probe I confirmed electrical continuity from the Blue and Red connectors on the PCM to the solenoids and other electrical components in the transmission. With VCM Scanner I was able to manually trigger the solenoids and listen for them to click. I am 100% confident there are no issues with the transmission wiring from the PCM.

The data log shows transmission commanded gear all over the place. From 1st to 4th and everything in between. It even flashes to 4th for a split second the moment the engine is fired up when it is most definitely in Park.

With the transmission shifting gears (all be it too early), seeming to work properly in reverse and not making any noises, I suspect it is mechanically OK. Confirming electrical is good and the tune is not to blame the only thing left is the transmission hydraulics.

What do you guys think is the problem?

Would you suggest changing the valve body with the transmission still in the car? I am doing everything I can to avoid having to buy a new / rebuilt transmission, pulling the transmission will be no fun at all.

I will attach my most recent log file tonight.

Thanks for reading my story.

 

I don't think a 1996 transmission is compatible with a 2002 PCM. If that is not the problem it could also be a defective manifold pressure switch.

 

The transmission is connected using the factory LS harness and uses exactly the same connector at the trans so I think it is compatible. I am able to command solenoids with VCM Scanner so I know there is some communication there.

My tuner says that the segment swap is most likely NOT the problem.

 

What year is your transmission and PCM?

 

1996 through 2000 PCMs and Valve-Bodies are a set...
and 2001 through 2006 are as well.

However they can be made to be interchangeable, by doing away with the PWM function for the TCC.

 

If I recall correctly, the transmission is 96-98 as it has the shorter bellhousing and a torque convertor adaptor to fit into the LS flexplate
The PCM is from a 2000 Silverado with red and blue connectors.

 

So I should be good with a 1996-1998 trans and a 2000 PCM?

If not, can I put a newer valve body in the transmission so it will be compatible?

 

I believe my trans has a GM048 valve body, based on the Sonnax link here. Sonnax Remanufactured Valve Body - GM048 this was used from 96 to 2000.

Should I use the GM048 valve body or go to a newer GM049 valve body that was used 2000 to 2002 with annular lockup?
My PCM is from a 2000 Silverado, serv. no. 09354896 (0411 PCM) with a transmission segment swap from a 2002 Camaro.

Do you guys think I should change out the valve body with the trans still in the car?

 

from 96 until around 2009, you can always swap a newer unit into an older unit.
96-04, for all intents and purposes, are totally swappable from an ecu standpoint. the ecu doesn't know or care if you have a 2000 or a 2002 or a 2004 etc
All the solenoids are the same, the connector is the same, it's all the same.
2003 they swapped to a different EPC solenoid...but it makes no difference in my testing. the case connector is the same and it works just fine.
Even units with ISS can be swapped into older non-ISS applications because the ISS is on otherwise unused pins in the case connector

Simply put, the year mis-match is not the cause of your issue here.

If I were you, I'd build a super simple manual-shift sub harness and just make sure the trans is functioning properly before anything else.
This almost certainly sounds like a trans control issue to me. **** tune, bad sensor input, etc
Not AFL
not computer mismatch
etc

 

Excellent information, exactly what I was looking for.

I don't need to build a manual shift harness as VCM Scanner gives you the ability to manually select gears in their program. I would have to put the pan back on and refill with fluid to test it though. I did feel the trans shift and it works fine in reverse so I want to believe it is mechanically OK.

"This almost certainly sounds like a trans control issue to me. **** tune, bad sensor input, etc"
What are the chances something is screwed up in the valve body thus incorrectly routing fluid or letting fluid leak past a valve or check ball (or something) and causing the premature shifting?

My tuner says there is nothing wrong with the tune. What sensor inputs is the transmission looking for? Could I have a problem with the manifold Pressure Switch? That would be an easy part to swap if there is a chance it is the problem.

 

The guy tuning it is saying nothing wrong with the tune

The guy stealing from walmart always says he didn't steal anything from walmart
if you have VCM Scanner...you can easily do a scan and see if the tune is screwed up or not.
You can watch and see how gears are being commanded.
The only thing that is going to make this shift is the shift solenoids. They are commanded by the pcm.
The manifold pressure switch doesn't make it shift
the 3-2 doesn't make it shift
the TCC solenoid doesn't make it shift. etc

if there was a specific shift issue (no 4th, starts in 2nd, etc) we could narrow it down.
But if you're saying it starts in 1st then just goes 2-3-4 really fast...there's a different issue

 

I have to trust my tuners word. I am using LSX Power Tuning, as I understand they are pretty reputable.
Most recent data log and tune file attached. please take a look and let me know what you think.

 

A number of things can affect shift timing , TPS, VSS, MAF and more, even if the tune is set with all the numbers correct any one of these sensors sending an erroneous signal can cause issues,
Few years ago had a customer i was trying to to help with similar issue with his normal driving shift was fine when he floored it however would shift through all gears by 45 mph.
Ultimately it was a Maf/Tps calibration issue and no codes had been set.
As for the trans it can only do what is commanded.
Frank@performabuilt

 

Yep, I'm with frank.
Just like I mentioned in my first post...bad sensor input can cause screwey issues.

 

Thanks for that Frank, but the engine is running well with no indication anything is wrong with any sensors. All the sensors are new and either AC Delco or Delphi brand. My log file is attached above, I would welcome you to take a look and see if you see anything erroneous.
I have a sneaking suspicion I may be replacing the transmission. I think I will put the pan back on this weekend, refill the fluid and give it another try. This time I will attempt to force shift with VCM Scanner. If I still have no success I may make a road trip from Cincinnati to see you guys.

 

Do you see anything out of line in my tune posted above?

 

I put the transmission pan back on today and filled it back up with fluid.
Left the car up on the Quick Jacks and started it up, wheels in the air.
Put the transmission in D and let go of the brake and the wheels speed up to 48MPH (1:24, log 8.1)
Interestingly the commanded gear always shows 2.

Log 8.2
From 0:33 to 1:07 I am manually shifting from OD to D to 2 then 1, each time I let off the brake speed jumps up to about 35 MPH.
Again commanded gear remains 2.

From 1:19 to 1:46 I am force shifting using VCM Scanner,
1st on - speeds up to 30MPH (1:20)
2nd on - speeds up to about 35MPH (1:30)
3rd on - speeds up to 50MPH (1:37)
4th on - speeds up to 62MPH (1:44)

I then repeat this and get much the same results beginning at 1:50.

Am I stuck in limp mode?

Please help guys I am lost......

 

Every time I have had an issue to where the commanded gear did not equal the position the shifter was in, the manifold pressure switch was defective and the trans would not shift correctly. I will say that the transmissions with a defective manifold pressure switch did not stack shifts though. When I am trying to solve a problem that is really eating my lunch I like to repair the things that I know for sure are wrong and most of the time that will take care of the problem that I am having.

 

There in lies the problem, something is wrong, but I don't know what to go after. Hell I would buy a new transmission if someone convinced me that's what I need.
I am starting to wonder about the PCM but I think that would give me a CEL. I am totally stuck at this point.

 

I would look at the data from the manifold pressure sensor make sure it is telling the PCM proper manual gear selection. Check that no cells are turned off in the PCM TUNE.
SENSORS can be off without setting a code as long as they are in the specified range .
I would take trans off the table first though I do not think it is the issue by building a simple shift box first and commanding shifts with it. This would take bad grounds, shorted or loose wires, corrosion off the table and make sure trans is sound.
If sound then i would consider flashing tune to stock (save the tune you paid for) and by tune i mean entire tune not just trans a swap. Then drive and see how trans does and watch data .
Also try unplugging the MAF this will set a code but will place PCM in speed density mode and take MAF off the table .
If all of that fails and you have checked wiring very thoroughly I would consider a PCM swap .
The trans shift times and pressures along with lockup are affected by VSS, RPM, MAF, MAP, TPS Even battery voltage and alternator output and ground continuity any one of these or combination of them can cause the issues you describe.
As an alternative if all else fails you could consider an aftermarket controller for the trans such as USSHIFT which only uses TPS. VSS and RPM to make shift points and lockup
Frank