caburnside

Where is the brake sw located? and how do I check it? I really hope that might be the reason my TQ is locked up. I replaced the 3-4 switch, and the TQ solenoid and that did not fix the lock up. About to have the speed sensor replaced as it is reading a code that it is not working. But the transmission guy wants to go ahead and dig into the trans and rebuild, I just really hope the prob can be fixed without a rebuild.

1996 3500, auto, 10 plate, 370 injectors, ATS exhaust manifold, AEM Workhorse Air Intake, Boost, Pyro, Trans guages.

John Faughn

This is what both you & / or a shop should be doing , diagnosing whats wrong & then fax as needed , not replacing parts with a guess .
A code is almost a guess , its does not tell you what is wrong , it is only an indicator as to where the problem may be .
If its done right the first time it will cost less .

caburnside

I'm taking the word of my trans techs seeing as I got the same diagnosis from 2 different techs, he wants to do a rebuild. Claims there is debri in the valve body that came off the torque converter. And that this is not allowing proper flow causing the constant lock up. I just hated to think that could be the problem but after replacing the lift pump, TQ solinoid, 3-4 Solinoid and speed sensor I am going to let him take care of it. It just pisses me off because if I could have waited 3 more months I was going to replace the whole trans with a full billet DTT trans and I just don't have the funds at the molment so it wil be a mildly modified rebuild instead.

DAFF

Have a gas w350 with much the same issue. Replaced the filter and toped up the trans. Didn't see much in the way of debris. Added some Lucas to the trans and since then the trans seems to be locking up 70-90% of the time. This from once in a while. Also once it started to engage the batter and more fraquent it did so.

hope this helps

DAFF

jknowles4

Took the truck to a tranny guy today. He hooked up a scanner and said the truck was doing everything it is suppossed to. He thinks there is a bushing going out in the pump. I have no idea. Going to pick it up tomorrow and drive the thing until it blows. DAFF, I will try the lucas. Thanks for all the advice guys.

caburnside

You might have them drop your pan and look at the trans either way, mine threw no trans codes when it was scanned just a speed sensor code. But I saw the debri in the pan and the valve body, while it was very minimal they said it was enough to cause the problem.

Fueling around

After looking at your engine mods I think you roasted the tranny & TC, too.
DTT is not the only tranny option.

jknowles4

Ok this is weird,
I changed the tranny fluid and filter (last changed about 8,000 miles ago). Little bit of junk in the pan but not too bad. Replaced fluid (atf+4 and one quart of lucas). I added three quarts of fluid and the one of lucas and took the truck for a short drive. Converter locked, truck shifted well etc. Checked the fluid level and it was in the middle of the ok area. Drove the truck to work and truck did great. Checked fluid at work and it was still at the same level. Next day driving home I was waiting for the bank to open so I checked the fluid again and it was barely reading on the dipstick. Added 2 more quarts of fluid and checked level and it was at full. Drive the truck home and the converter didn't lock. Checked level at home and it reads in the middle of the ok area. Hooked to trailer and went to mow, truck never locked up. It tried a few times but never stayed locked. Should I drain some fluid back out or just drive it and see how it does? Everytime I checked the truck was in neutral and on level ground!!!

John Faughn

There may be several issue's here , a leak , the multiple things that control the lock up [ brake sw. , TPS , computer , fluid temp sw. ] , checking the fluid correctly - that sounds OK , but it would seem to me that if there is any showing on the dip stick - 2 qts would be too much [ but that's from memory ] .
Then deeper issues in the trans. like small bits affecting the valve body ?