Ok.....48RE, fully built trans (12,000-15,000 miles on rebuild)

About a week ago, I had a local shop adjust the bands, change the fluid/filters and installed the new larger BW #50185 HD solenoid and new transducer

It ran great and shifted very smoothly........two days later it started acting up.

When I was taking off from a complete stop the motor revs to about 1,500-1,600 RPM and will slowly take off........like it is bypassing first and going right to second gear or maybe even third gear

It starts, idles and runs fine........no smoke and no codes

When I slow down and come to a stop I feel a "bump" around 5 mph, like the trans is kicking down a few gears

At a stop, with the trans in neutral I can pull the column shifter all the way down the "1" and the truck has first gear......and I can then upshift as needed

Then one night, I drove to a friend house about 8-10 miles away, same symptoms as I posted above. When I left to come home, I now had first gear back! However, now the RPMs rev way up to around 1,800-2,000 before shifting somewhat hard into second

I took the truck into the trans shop on Tuesday. They took it for a test drive and also hooked it up to the scanner. They said the solenoid was definately the cuplrit and immediately suggested the GM Solenoid conversion

They said the only use the the GM Solenoid on the trucks with the better builts transmissions and said they havent seen any fail or cause any issues

So, I then ordered the GM Solenoid Conversion Kit and had it installed today.
No codes and had a perfect road test.

I drove it about 15 miles home and it ran GREAT.....Shift points were the smoothest it has even been

Then I pulled into my subdivision and lost first gear, AGAIN

When I am taking off from a stop the motor revs to about 1,500 RPM and will slowly take off........like it is bypassing first and going right to second gear or maybe even third gear, same as before!!!

When I slow down it has that "bump" at like 5 mph, like it is dropping down or skipping gears. Then, ocassionally when I am sitting at a red light, completely stopped, I will feel the trans "bump" like someone hit my truck from behind

I was running late and couldnt take the truck back to the trans shop........so it will have to wait until next week

Whats the next step? Remove the trans from the truck and inspect everything?

Here are my trans parts list that are currently installed in the truck:
Mag-Hytech Double Deep Trans Pan
BD FleX-Plate
Billet TCS Output Shaft
Billet IE Opie Input Shaft
Goerend Valve Body
Goerend Triple Disk Torque Converter 900/300
Diesel Site External Transmission Filter Kit
Sonnax Billet 4 Ring Accumulator
HD Band Anchor: "The Power Wedge"
Billet Rear Band Servo w/ Pin
Sonnax Dodge 16% Oversize Intermediate Super Servo
Sonnax Billet Servo Cover and Billet Pin
Sonnax Front Servo Piston Cover
Billet 4.2 Apply Lever
Billet HD Strut
GM Solenoid Conversion Kit

The trans has been flawless and taken about 550+ HP without any issues or hiccups over the past two years

 

I'm not the trans expert, but I would suspect improper band adjustment.

Another thing: Did they drain the fluid or flush it?

 

They just drained the fluid....from whatever was inside the MH DD trans pan

 

Then they dropped the pan right? The one band adjustment is inside.
And I believe the 1-2 band is the outside accessible one. That's the one that people screw up easily because you have to torque the bolt down to X inch pounds then back it of 2 3/4 turns. And if you don't get all that exact, well, it starts doing what you describe. That front drum is spinning when it should be stopping and the band isn't releasing or engaging to make the drum behave....

You know I've been in there and done all this stuff, but my memory for some things is just terrible. I actually mis-adjusted my front band once and had some shifting issues then re-adjusted it and they went away. So when you read my advice, feel free to substitute rear band for front, 1-2 for 3-4 or anything that works for you.

My point is that the band adjustment can do this (as can the solenoid and a whole host of parts) so I think you should first read up on other posts from peeps with a better memory than I have, and see if anything they wrote rings a bell.

We have many trans experts here and I don't know why they aren't saving me, but I can tell you the search function works well and there is a ton of info available right on this forum!

 

It does sound like the front band is out of adjustment to me too.

 

Yes, they did drop the pan and replaced the filters and fluid

 

Then I would ask if they found a lot of crud on the magnet (front band is weak and shreds easily) and I'd readjust the bands so you know they are right. If that doesn't work I think you are left with the solenoid and sensor swap (they can be bad from the box) and if THAT doesn't work, well, you have been saving up haven't you?


EIDT: You probably have a solid front band with your rebuild so this may not apply. If they somehow used a stock band I'd worry.

 

x whatever on the band adjustment... you may have burned the band by now too.

That is all on the tranny shop.

 

Just to let everyone know, the lockout and overdrive solenoid's internal wiring harness was bad, and causing a short......thus blowing and popping all of the tranducers

Fixed and running great

 

awesome news!

 

sweet