Trans Question - Rough shift 1st and 2nd gear

[Tonyrodz]

Damn 80psi oil pressure

Good catch. Nah, the sensor was bad. Eventually my cam bearings went bad in this motor--another one in the works tho

 

[JonnyTahoe]

G80 most common.

 

[Randy Hill]

Hopefully yours is another issue, but I had another vehicle with similar symptoms, and it turned out to be that the transmission was just getting worn out. The tolerances between the moving parts had just began to allow enough fluid to move through the system that the fluid pressure at normal speed was low and it didn't shift until the rpms got high enough for the pump to develop adequate pressure, and then it would shift hard in the first two gears. If I had my foot into it, it shifted fine, but if I was driving normally I would feel it. I tried changing filter & fluid, then some additives with no improvement, ultimately just had to get it rebuilt.
Again, hope you find a better outcome.

 

[HiHoeSilver]

Okay I attached the little card that's in the glove box. I have to decipher it. In terms of the ride, I measured 33 1/4" between the rear fender and the ground, 32 7/8" from the front fender to the ground and approx 70" tall to the roof, not the rack.

View attachment 252060

Great. Fyi, you can hit the GM customer service chat window with your VIN and email and get the build sheet that covers all the codes. You can also look them all up.... lol

I wonder if you're lowered at all. Seems a bit low.

G65 Autoride toast, I bet.

I have the same ratio, it's a great compromise imo.

The best, imo. I don't mind my 3.42, but then I get back into the 3.73....

ZW7 Premium Smooth Ride and G65 Nivomat rear shocks. Unless they've been changed...

Bingo. Do you hear the compressor running? Do you have a "service ride control" message?

 

[Fless]

Bingo. Do you hear the compressor running? Do you have a "service ride control" message?

Shouldn't have a compressor with the Nivomats. They adjust manually with no external connections.

 

[HiHoeSilver]

Shouldn't have a compressor with the Nivomats. They adjust manually with no external connections.

Oh yeah. You're right.

 

[RET423]

My son in laws 04 Sierra had the same issue, we changed the 1-2 and 3-4 shift solenoids and the pressure switch (all accessible by dropping the pan) and it shifts like new now; good time to flush out the old fluid and replace the filter.

All 3 solenoids were less than a hundred bucks on Amazon so with the new fluid and filter it was a pretty affordable fix.

 

[dwinters14]

I finally got under the truck today to take a peek at everything. I also have been driving her the past few days and the transmission does the hard shifting intermittently. Sometimes it shifts rough and sometimes it shifts smooth as butter. No leakage from what I saw.

To start, I want to do a full flush with a new filter and see how she feels after that.

The suspension is aftermarket I believe, the shocks and springs are blue and the springs had a name on them I just didn't write it down. I think the truck is lowered purposely because none of them were leaking.

On another unrelated note, I need a bunch of suspension parts (Wheel bearing, ball joints and end links) and I have zero experience with American cars and their aftermarket brands. Can you guys suggest some brands/websites for things to get? My list is long right now and could grow as I fix things:

New cluster lights
New drivers side window switch
Passenger side wheel bearing
Passenger side LCAB
Passenger side sway bar end link
Drivers side UCAB & LCAB
Drivers side sway bar end link
Rear axle sway bar end links
New windshield
New windshield washer fluid pump

 

[ncalvo]

New cluster lights

I had my cluster repaired by someone on ebay, shipped it out to them in AZ i believe, they found several grounds, replaced the motors and also installed blue led's to replace each bulb. Took probably 2-3 weeks from shipping it out to getting it back. Only around $60-70 total.

Also for the rough shift 1-2 I had/have this issue as well. When cruising through my neighborhood at real low speeds my shift is delayed and clunky, where really getting on the throttle it shifts much quicker.
I brought the truck to a transmission guy in Jacksonville and he took a look and said its not the trans it is probably a motor issue for me. Anyways I had him go into it, he ended up replacing the boost valve to up the pressure and he said everything looked just fine. Wasn't really necessary but it is what it is.

I got a new TPS just on a hunch, but turns out I have to replace the entire throttle body because that sensor is riveted to the side. I got a reduced engine power one day, took off the throttle body and cleaned it, went away. Luckily I was already on this path so when the new throttle body came in a few days later I put it on and no issues. I also noticed my shifts had cleaned up a bunch, it felt much better.

Now I am battling a different weird issue, I get vibration at my pedals almost like my bearings are shot but they aren't. I am thinking motor mounts. My tahoe is also very clunky I think it is time to replace some other bushings and such.

 

[dwinters14]

I had my cluster repaired by someone on ebay, shipped it out to them in AZ i believe, they found several grounds, replaced the motors and also installed blue led's to replace each bulb. Took probably 2-3 weeks from shipping it out to getting it back. Only around $60-70 total.

Also for the rough shift 1-2 I had/have this issue as well. When cruising through my neighborhood at real low speeds my shift is delayed and clunky, where really getting on the throttle it shifts much quicker.
I brought the truck to a transmission guy in Jacksonville and he took a look and said its not the trans it is probably a motor issue for me. Anyways I had him go into it, he ended up replacing the boost valve to up the pressure and he said everything looked just fine. Wasn't really necessary but it is what it is.

I got a new TPS just on a hunch, but turns out I have to replace the entire throttle body because that sensor is riveted to the side. I got a reduced engine power one day, took off the throttle body and cleaned it, went away. Luckily I was already on this path so when the new throttle body came in a few days later I put it on and no issues. I also noticed my shifts had cleaned up a bunch, it felt much better.

Now I am battling a different weird issue, I get vibration at my pedals almost like my bearings are shot but they aren't. I am thinking motor mounts. My tahoe is also very clunky I think it is time to replace some other bushings and such.

Yes that is exactly what I've noticed. Slow speed driving first gear is clunky and it revs out. 2-4 is smooth as butter. I'm almost wondering if it's as others have said, that the first gear is designed that way as I notice the torque and get-up-and-go is quickest in first gear. If I punch it even a little it'll shift smoothly and this is consistent.

Either way I'm going to leave it. The fluid color is good and the overall driving experience feels great and if it needs to replaced i'll do that. The truck has 200k. I did a 0-60 test and the truck was about a second slower than it is from the factory, so I'd assume most things are working right.


As for my cluster, I ordered a reman from Carparts and everything works except my trip mileage. I'm sure it could be fixed by someone locally to get it working as I'm assuming it's a computer error inside the cluster, but the important thing is all my lights are back and the stepper motors work properly.