2002 Hummer H1: Is my Overdrive Gone?

[omoige]

I was driving my H1 the other day and discover that my truck will not go into overdrive and suddenly started overheating. When I slowed down, the temperature came down, but still did not go into overdrive as my engine rev high and RPM went over 2000 going about 45 MPH. Not sure what the digital reading is since I don't have numbers on my temp gauge. But what surprised me most was when I put my Tech2 to the truck, it stated that my transmission overheated. It has a reading of 251F.

When I try to go into reverse when engine is cold, everything is ok. But when it heated up to the 251, I had to rev the engine a little higher before it kicks into reverse. And it puffs a lot of smoke...black smokes while going backward.

Now I got the following codes: P0219, P0236 and P1656.

Is the transmission now bad? Or if I change the oil will it be okay? Or is the engine overspeed that is preventing the transmission from going into overdrive?

What is gone wrong with this truck experts? I just put a rebuilt transmission
with high-end stuffs in this truck just a few weeks back and its been fun till now. I am using the DT4 transmission fluid from Redline Oil. Please help guys. I am now scared to drive this truck now. I don't want to break anything.

[DmaxMaverick]

Sounds more like the TC isn't locking, or is weak and slipping. If the TCC isn't locking when it should, it will set a DTC. If it's slipping, but not excessive, it may not set a DTC. If OD doesn't engage, it will set DTC's and likely go into limp mode. If the tranny overheats, as indicated by your scan, it should go into limp mode and set codes according to the fault.

If you are using an OEM/stock torque converter, with an over-built tranny, especially with a hardware shift kit, the weak link then becomes the TC. Check the fluid for color and odor. If the fluid checks OK, drive with the Tech II and monitor the tranny performance in real time, verifying solenoid command/actual, TCC lockup, and in/output ratios. Slippage of less than about 2% may not indicate a fault, but may be enough to overheat.

[omoige]

This what I have in the truck:
STAGE TWO REBUILT 4L80E TRANSMISSION WITH BILLET TORQUE CONVERTER AND EXTERNAL COOLER KIT RATED AT 30,000GVW WITH 2YR UNLIMITED MILE WARRANTY

It has been performing great until couple days ago. I think it has to do with the turbo thing.

Please explain to me, when the transmission goes into limp mode, does that prevent it from going into overdrive?

And by the way, the fluid is not totally pink as it came out of the plastic, but it still pink and doesn't smell. I am comparing it to the smell from the old transmission that I removed. It was REALLY smelling burnt, but was still running before I changed it. It was only not going into reverse. And when I drained it, I forgot to drain the cooler.

[omoige]

This is what I have in the transmission according to the Transplus in Tampa FL:
Power pack for first and second gear, rest of clutches Redline filter,Heavy Duty Sprag Tugger shift Kit by Transgo, Kevlar Band etc etc.

Believe me, I love the transmission. It moves effortlessly and over takes like a car. I only have to control my speed since I noticed that it get hotter once I am doing over 65MPH. I always slow down back to 55. But gets up readily and easily than the old trans.

What if I change the fluid?

[DmaxMaverick]

Limp mode may do several things (or prevent several things). It will lock out OD, and prevent TC lock. Much depends on the initial cause. It may also allow only one gear, usually 2nd. If it's shifting and driving fine otherwise, there may be an issue with the band adjustment, but it should set a DTC if it's slipping or not engaging.

Absent any DTC's that may help, changing the fluid should be the first measure. If the tranny was previously "burned up", the drum may be under-spec, causing a poor tolerance for the band. It's easy to see (and measure) at overhaul, so it should have been replaced, if needed.

[DmaxMaverick]

Also, "new" doesn't mean it can't fail. A new $1500 torque converter is easily defeated by a "new" $20 solenoid. If it's still under warranty, I'd go back to the shop that did the overhaul.

[omoige]

DmaxMaverick, it wasn't an overhaul. It was an outright $2600 built transmission. Everything inside is suppose to be new and supposed to be an upgrade version of mine. That, so far was noticeable within the past 4 weeks that I have had it installed.

The builder is sending me a couple of solenoids. He said all it takes is just a minimal clogging of one of these solenoid and it would do just what it is doing now. But meanwhile, I will change the fluids and see how that goes.

I am just hoping that this is not caused by anything from the truck's engine. I also plan on changing the turbo to a new one that I just got on Ebay. Supposedly a military version of the turbo.

DmaxMaverick, I must confess, you knowledge about these engines amazes me. I have read so much from your contributions to problems around here. You should be kept alive forever for those of us who need your expertise man. Thanks for being you.

As mucha s I enjoy this truck, I don't know if I would have thrown it into the ocean not for this helpful resource from this forum.

By the way, I was able to get the TDC offset now dead on -1.94. Thanks to you and others from this forum.

[DmaxMaverick]

It's good they're working with you on this. Solenoids are easy to replace, but require draining and pan removal. A good time for fresh fluid. If your pan doesn't have a drain plug, now would be the best time to install one. The best option is to either replace the pan with an aftermarket that has a drain, or have a bung welded onto your pan. Stay away from the threaded bulkhead type fittings. They will usually leak after a short period, and require pan removal to tighten them, which pretty much defeats their purpose. There's right ways and better ways to do it. Just ask if you need more info on the simplest/best solution.