46re trans, 97 SS/T. Wont stay in OD, torque converter will not stay locked as well. This video shows how the trans is acting. Light constant throttle, also has trouble shifting into OD and locking the converter. New fluid and filter about 3K miles on the change. Bands were also adjusted. Hauled a car yesterday about 800 miles and at the last 30 miles had to limp it home. Also have an external cooler. I think it got too hot climbing the last mountain and cooked the OD clutch pack? When the OD is disabled, it doesn't want to lock the torque converter. Fluid level is full, right on the "full" line, but I did notice some bubbles on the dipstick. Any advice?


https://www.youtube.com/watch?v=gwxe...ature=youtu.be


To add, tried a WOT blast in 2nd gear so see if the trans would slip, will hold 2nd gear but suddenly drop out of 2nd gear and bounce off the rev limiter, well before the shift point.




If the trans is cooked, I need to know the recommended parts list to return/rebuild the trans to good working order, would also want a shift improver kit, such as the sonnex or transgo. Opinions needed.


Thanks!






*edit* will not be able to access internet for a couple of days due to moving, but will check back for advice just as soon as I can!

 

We're u towing in OD?

 

You do know not to use the overdrive when towing right? If you did you probably fried the od. Lock up applies after going into od.

 

I think the TC will go into lockup in 3rd also when OD button is off. At least mine will. But OD and towing don't mix.

 

Why,and please be specific. With the gearing the engine is revving at 3k at 65mph in 3rd. It didnt start acting up until after climbing at mountain up to 4000ft, and that was in 2nd gear. If i need to add some clutches and steels to OD to beef it up thats fine with me. Ive been towing with this truck for 50k miles using OD on straight and level roads, and this is a junkyard trans. No WOT shifts into OD and i will not use it on any kind of inclineto keep shifting to a minimum. Looking for a course of action now with some suggestions for good parts.

 

it isn't simply the strength of the O/D unit that causes issues. It's the heat generated by putting a heavy load on the .69:1 gear ratio. It literally cooks the fluid, and transmission failure follows shortly thereafter. Of course, the PCM should have turned on the trans temp lite, and disabled O/D on its own....... unless that particular part of the sensor isn't working properly.

Have a look at your fluid. Make sure there is enough in there, and it ain't burnt.

Other than that, you have classic symptoms of failing TPS.

 

So towing in OD places a heavy load on a gear ratio, causing it to fail? I could understand if the trans was constantly shifting in and out of OD, and the slipping of the normal engagement could cause excessive heat build up. I could also understand if the TC wasn't locked the entire time and the coupling of the TC could cause excessive heat build up. I just don't understand what you meant by placing a heavy load on the ratio, were you talking about stress on a certain bearing?


I checked the fluid, it is in great shape, no signs of burning, no unusual smells, also right at the full mark, engine warmed up and running, in neutral.


Thanks for mentioning the TPS, I completely forgot that the PCM relies on TPS for trans functions. The way the trans is acting does seem like the TPS is encountering an internal short at light throttle. I had this issue on one of my other cars, and due to the short, the PCM would reset the baseline TPS reading, causing severe drivability issues. I wish I could read the data stream on this thing.


Thanks!

 

No, the heavy load generates heat, which causes the trans fluid to cook, and stop doing its job. (lubricating things.)

 

No joy with the TPS still has trouble shifting into OD or locking the TC. Reading thru the troubleshooting flow chart, next course of action is going to clean out the VB and all associated circuits. Also, it doesnt slip at all when OD engages or the TC locks.

 

Years ago I had a 94 with RH trans with similar issues, in my case TCC and OD stopped working due to the trans cooler being clogged. The clogged cooler reduced pressure mostly in just the TCC and OD hydraulic circuits, the others were fine. I discovered accidentally when I was trying a quick fluid flush by removing cooler return and nothing at all came out with engine running in neutral. Just to check I connected the cooler lines in reverse and it blew out some debris.

The debris was from the trans coming apart, but I got an extra 10k out of the trans by clearing out the cooler and using an inline trans filter in the return line.