well tomorrow my truck is getting a donor trans put in. I've been a member here for a long long time but haven't posted in a long time either. Enjoy the read!

Back story: Bought this '04 cc/sb in March. 230k KM/ 143k miles, head studs, reman turbo, EGR delete, air-raid CAI and 6" lift. Put some 35's on and an SCT sf3 tuner and ran the canned performance tune since then. Transmission always had a bit of a stutter from a dead stop but barely noticeable, it hammered through the gears at WOT rollin'coal like a freight train with me behind the wheel grinning like a little girl who just got a pony for her birthday.

About 2 months ago it started delaying going into reverse from park, by 2-4 seconds and it would act up if I pulled hard in 5th I think. It would take a moment to upshift or it would be a really soft exaggerated shift from 5-6 (I think) but it still seemed to be alright. Hindsight...

Then our frigid, snowpacked northern winter kicked in and my now bald 35's and an aggressive ramp rate on the performance tune were seemingly suicidal...as much fun as redline 50 mph 4wd drifting is, I figured it was a good time to put it back to stock and let the computer relearn the shift points, thinking that was the reason for my quirky shifting between 5-6.

I returned the programming to stock, it shifted into reverse immediately and I'm feeling pretty smart. Take it on the road, 1-2-3-REV-SLAM-REV-SLAM-limp mode. Crap. In limp mode it would 1-2-3-(4/5) no problem but it wouldn't run 6th gear. Put it on street tune, turn firmer shifts on, crank up the 3-5 shift pressure, same thing. So I leave it and nurse the 3-5 shift hoping it will relearn...it eventually does and shifted nicely, but I was slipping in 5th now sometimes on a downshift pull. Crap again. It doesn't slip and I still don't have 6th while in limp mode.

So I took it in to my local shop and they drained the fluid, pulled the pan. HOLY CLUTCH FUZZIES ON THE PAN MAGNET! There was enough friction material on there to fill a couple shot glasses. Well it's christmas and I've got a 600 km/ 375 mile drive to make in a couple days to visit family and salvage transmissions down there are half the price of where I live, so you betcha, flush the system, stick a new filter in, slap the pan back on and give the girl some fresh blood. We're hitting the road.

I made the 7 hour drive not too bad, but by the time I got here it was really hard to keep from slipping and now its not shifting down when I come to a stop unless I have tow/haul engaged. So I drive about 160km/ 100 miles today round trip to pick up a donor trans and take my truck to the shop, the last 15 km or so I only had 1st to 3rd gears 100%, I would say 5th and 6th were only good at idle-1500 rpm...by 2000rpm there was barely enough engagement to maintain speed. So I pull off the highway and give the beast a good ol turbo screamin, tach pegging, tire burning, 4wd drifting good time from 1st to 3rd into the shop parking lot and there she sleeps tonight with the donor gear switcher box in the back.

What I'm curious of now is what the actual problems were throughout the failure so I can look out in the future and possible prevent it/them. Aside from my driving style obviously. I put some fluid in 2 months ago because it was a tad low it looked to me (1/2 quart) and it looked and smelled fine. When I serviced the trans it was brown and smelled terribly burnt.

Can anyone make anything from this?

 

I think that sums up quite a bit right there. I'm sure Mark would have some things to add to this.
It's a stout trans. to be sure but anything will only take so much abuse and mods until things are compromised .

 

Upgrade to the 08+ trans pan with the internal filter while you are replacing the trans. You probably will want to change the internal filter a LOT more often than the 60k miles if you cause that much wear.

 

Sounds like what happened to mine when it wasted the direct clutch

 

I'm confident in saying this, but not 100% sure that 1-2-3-4 all work fine and I'm pretty sure that's what limp mode would default to. I'm not sure what clutches do what so I can't figure out what failed, but I think whatever changes to go into 5th is my answer.
I saw a post mark made where he described that this trans is essentially two transmissions in one case, a two speed in the front and a 3 speed in the back. Then he explained the functions to make it all work. It was a great post but I can't find it now.
A curiosity I have is if a solenoid failed and took the clutches out or if the clutches failed and took a solenoid out.

 

Your solenoid is probably just fine

 

This "limp mode" that everyone talks about is mostly a myth. There are no "default" gears. When the PCM detects that it can't get one or more gears, it stops commanding the problem gears. So if your overdrive isn't working, it won't command 6th gear (which is what the PCM calls the overdrive gear.) But since the same overdrive clutch is also used for 2nd and fourth, it won't command those gears, either. So you would have 1-3-5 and reverse.

From your description I can't tell what failed, either. But it's really academic, because no matter what failed to answer still is take it out and rebuild or replace it.

Chances are the clutch failed first.

Like this?

First, you need to understand how the TorqShift was built. It is a two speed transmission in front of a three speed transmission.

You can get six ratios by combining the two times three ratios. The problem is that two of the ratios are nearly identical.

The two speed has ratios of 1:1 and 0.71:1.
The three speed has ratios of 3.1:1, 1.54:1, and 1:1.

By combining them you get:
3.1:1
2.2:1
1.54:1
1.09:1
1:1
0.71:1

The 1:1 and 1.09:1 ratios are nearly the same. Less than a 10% change in RPM during a shift is useless. The customer (YOU!) would interpret this as a problem and take it in to get fixed.

It was done this way to save money. It was much less expensive to design the trans like this than to design and build a true six speed. Later that was done and was called the 6R140.

 

Can you retrofit a 6R140 into a 5R110 application? B.

 

You can do anything that you have enough time and money for. To do this you'll need to make a custom wiring harness, a custom computer to run the transmission, and write the software to make it all work. If you're asking is it a simple bolt in, no, not even close. It would be a very hard and demanding task to make this work.

 

Dang! I was ready to get all excited.

 

Okay thanks it can't hurt to ask. I'm happy with my %r110 and it can be rebuilt better than ever when she finally does need it. B.