T AM

iTrader: (5)

I've got a simple cam and bolt on car with a 73k mile 4l60e and a Yank 3600SS. Lately, the car has been throwing the code po751, and it wont make the 1-2 shift without hitting the rev limiter a few times. The fluid looks good. It's that red-ish/ pink-ish color. I have it set to shift at 6200 and the rev limiter is set to 6500. From what I've read, this means that I just need a new solenoid? Could it be a burnt band? Any ideas? Thanks, Andrew.

transam19

iTrader: (1)

u mite want to have someone look at your tune. usually if your hitting the limiter the tune is off. so start with that. is the tire size adjusted as well. but start off with someone looking at your tune.

Mike Morris

iTrader: (55)

How long has the converter been in the car? Converter usually causes the code and many people delete the code.

If converter has been in the car a while and no codes till recently good chance yes the Soleneod is bad and is easy and cheap to fix.

Try clearing the code first

T AM

iTrader: (5)

Mike, the converter has been in for the past 2,000 miles and no codes untill now. I've tried clearing the code and it still comes back. I'll go ahead and replace the solenoid. Hopefully that fixes it. Thanks.

Mike Morris

iTrader: (55)

Hmm thats a 50 50 shot. Good luck. if it comes back on after replacing-have your tuner delete the code.

01ssreda4

iTrader: (96)

First thing, put down the wrench. MPH must be met first before rpm comes into play when commanding a shift. A simple drop in 1/2 commanded MPH may be all that's needed. You need to verify your speed/mph (at the time of the shift) vs. whats in your tune before you go replacing anything.

T AM

iTrader: (5)

So, if this isn't set properly, it could make the computer think that the trans has a bad solenoid?? I'll double check the tune this week and report back, in case someone searches for this issue in the future.

01ssreda4

iTrader: (96)

Well I'm not sure what codes the trans with throw. Mine used to do it on the 2/3 and set a solenoid code. The problem with mine was I was commanding a 2/3 shift at 6200 AND 65mph. But, at 6200 I was actually going 63mph. Remember mph must be met first. My solution was to lower the shift mph to 60, which was met before 6200, then the computer would command a 6200 shift. This could be your issue as well, but you need to see what speeds vs. rpm you are actually doing then check the tune for discrepancies.

z99ls1

iTrader: (12)

Did you have the car tuned for the converter? I have had 2 aftermarket stalls in my cars and each one I put in made the car hit limiter from 1-2 before I got it tuned. Im 99.9% sure this is your problem if you haven't had the car tuned for the converter.

01ssreda4

iTrader: (96)

This may help you understand the tables in the computer:

https://ls1tech.com/forums/automatic...tm-w-pics.html

T AM

iTrader: (5)

Thanks

Yeah, the car was tuned and ran great/ shifted great until I swapped my 3.23 gears for 4.10s. I had the tune adjusted for the 4.10s, but it may just need to be double checked. Could be a simple error like 01ss mentioned, or it needs a new solenoid.

Gilbert@Ace Racing

I've been following this thread and haven't chimed in because you are getting solid advice. However, you are over thinking the situation.

The PCM will not think there is a bad solenoid if the shift tables are skewed. It simply will not command the shift. Period.

If it was good to go prior to the gear swap as you say it was, then think about it... what are the odds an electrical component failed immediately after the work on the axle was performed.

In the 1-2 shift table move the MPH down a significant amount and see how it responds. When I'm tuning a 60E I always like to see it shift with an rpm commanded threshold rather than a mph commanded threshold. The way to achieve that is to make sure the mph is low enough that the PCM is satisfied and then it will simply wait for the commanded engine rpm to be reached.

Like o1ssreda4 said... put down the wrenches. You're only going to create more problems for yourself there buddy. If you would like to discuss it in great detail I would not mind making the time to visit with you. All you have to do is call.

g

T AM

iTrader: (5)

I'm a little confused on this: "The PCM will not think there is a bad solenoid if the shift tables are skewed. It simply will not command the shift. Period."

It's throwing a code for the 1-2 shift solenoid. Also, it will do the 1-2 shift at wot; however, it taps the rev limiter before going into second. It will do the 2-3 shift without any problems. So, if something in my tune is causing the problem, I shouldn't be throwing a code for a bad solenoid like I am right now? Correct me if I'm wrong, but it has to be commanding the 1-2 shift because it is definitely allowing it to happen. Seems like this all leads back to the solenoid? I appreciate the help, Gilbert.

T AM

iTrader: (5)

Also, I had the tune changed to shift off of RPM and the problem still persists.

Mike Morris

iTrader: (55)

Go in the tune and drop the speed by about 3 MPH on the 2-3 shift. Verify in the tune that the tire height and gear ratio is correct.
As mentioned speed must be met then RPM for the shift to occur at WOT.
Another test to see if its a tune problem is to do a WOT run where the 2-3 shift occurs. Try it in without OD and with it. Its it shifts into 3 withoutbanging the limiter on the 2-3 shift in OD its the tune.

transam19

iTrader: (1)

one thing you want to make sure is that your full throttle tables match your part throttle. only from 94% to 100% so what ever your mph is on the full throttle table, it should match in the part throttle tables. and do it on all part throttle tables. as mike morris said try going down on the mph as well.