4t60e TCC solenoid *again*

How many miles does car/trans have on it? Any check engine light or codes? Does engne performance otherwise seems normal?

151k on the engine, about 25k on a rebuilt tranny. Yes, I am getting a code 30 - TCC / Knock Sensor failure. The engine seems to run fine for the most part. I was having a problem with the engine pinging pretty badly when the TCC was locked up & I started going up a hill. I thought the pinging was more of an ignition / egr problem, but maybe not.

151k on the engine, about 25k on a rebuilt tranny. Yes, I am getting a code 39 - TCC / Knock Sensor failure. The engine seems to run fine for the most part. I was having a problem with the engine pinging pretty badly when the TCC was locked up & I started going up a hill. I thought the pinging was more of an ignition / egr problem, but maybe not.

Do a google search on 4t60e, lockup, and tcc and you will find plenty.

You may have a valve body problem: look at the sonnax info:

Bob

Yea, i have a 96 4l60e that has the dreaded 1870 code. I wanted to put the sonnax kit in, but buying the reamer for a one time repair is a little steep. still researching the issue. Thought about a ebay valve body also.

Bob

GM did have a few problems with the valve body in the 90's. Give them first shot even though I know you are way out of warentee. Seems we were reaming out the valve bodies from time to time. BTW, if you are doing the reaming yourself you may be able to rent one for a few hours.

Since that trans was rebuilt not long ago, wouldn't the inherent valve body problem(s) have been addressed? Also, the fact it was pinging while in lockup--and under load--makes it seem normal for it to go out of lockup in an attempt to address the pinging. What if you were to replace the knock sensor: then the timing would be adjusted accordingly under load to eliminate knock and no problems would be detected and thus the trans might remain in lockup. You already have a set code for knock sensor anyway.

Well, where is the question. Most of the local parts houses don't carry trannie parts like the sonnax kit. SO if they don't carry the valve, there NOT going to have the custom reamer tool. Been trying to find someone who works on trannies on the side that might have one, but so far no luck. The reamer on line is at least $125 Plus shipping. Most trannie shops around here don't want to here about a valve body repair. They just want to rebuild the whole unit. And the trannie shop is certainly not going to rent me a tool.

There are other kits that just replace the valve and you have to drill the valve body i believe, but the sonnax kit with the insert seems to be the way to go. I think the other method just puts the TCC apply to max rather than fix the problem.

The other thing i was thinking was a valve body replacement, There was a guy on ebay selling virtually new (or so he claims) 4l60e valve bodies used for some kind of testing. Thought he said 05 models. With the right separator plate, he said they would work on my 96. SO far i have not took the plunge on that gamble. They have been going for `150/175 or so when this guy had them listed. There is another guys selling used bodies out of working trannies, but it a crap shoot that they don't have the bores wore also. There a LOT cheaper, but it seems a much bigger risk of doing the job twice.

Bob

I'd be very curious to see whether a scan tool indicates a lock-up command or not under the conditions you've described. In order to have the TCC engaged, transmission temperature has to be in a certain range, engine load (comes up as "LV8" on a scan tool, IIRC) has to be in a certain range, and throttle position sensor has to indicate a certain range. The OEM shop manual will have more information on this. For example, if the transmission fluid temperature's too high, the TCC will NOT lock up -- this is done to cool off the transmission. Can you borrow a scan tool for a weekend?

I *think* your vehicle has TCC related diagnostic trouble codes (high-end GM products since at least the late 1980s had them -- the PCM looked for an RPM drop in a certain range within a certain time after the lockup command was given, bumps a counter every time it doesn't see this, and if the counter exceeds a predetermined value, turns on the MIL.).

Regards,

Bohdan

Whitey wrote:

A 1000 rpm difference seems pretty big for lack of lockup. Is it possible it's not staying in OD?

I pulled off the road to see if I could find