How Does Your Tranny Shift?

KyRob · May 30, 2007

When I take off slow and easy,below 2000 rpm, my trucks shifts very hard going into 2nd. I mean you can really feel it jerk. If I take off faster, it shifts smooth. Doesn't make sense but that is what it does. Also, 8 out of 10 times when it shifts from 2nd to 3rd, you can hear a clunking sound. Truck runs out fine and makes no noise other than during the shift but it make sme wonder. Any of you have any ideas on this or if it is something to be concerned about? I plan on having the service guys drive it but figured I'd ask here first. It's an 04 4x4 Xtra cab Sierra if that makes any difference. I have driven a Toyota 4x4 for 17 years before getting this truck in January so I have no idea if these things are common in these trucks.

Thanks,

Rob

thecraft · May 30, 2007

I don't think it's anything to get too concerned about, but that's definitely not normal, I can barely feel mine shift.

VMax2007 · May 30, 2007

When I take off slow and easy,below 2000 rpm, my trucks shifts very hard going into 2nd. I mean you can really feel it jerk. If I take off faster, it shifts smooth. Doesn't make sense but that is what it does. Also, 8 out of 10 times when it shifts from 2nd to 3rd, you can hear a clunking sound. Truck runs out fine and makes no noise other than during the shift but it make sme wonder. Any of you have any ideas on this or if it is something to be concerned about? I plan on having the service guys drive it but figured I'd ask here first. It's an 04 4x4 Xtra cab Sierra if that makes any difference. I have driven a Toyota 4x4 for 17 years before getting this truck in January so I have no idea if these things are common in these trucks.

Thanks,

Rob

Check your fluid (level and purity). Have it flushed and new filter.

KyRob · May 30, 2007

Guess I should add that the truck only has 25,000 miles on it. Think the fluid would be bad this soon?

Rob

asilverblazer · May 30, 2007

No, is the tow haul mode on or off?

KyRob · May 30, 2007

Tow mode is off.

Rob

AdamG · May 30, 2007

Mine does similar when going from a dead stop into first.

56k miles, I doubt its ever been serviced before...

asilverblazer · May 30, 2007

What happens when it is on? Maybe it is switched backwards or something similar... On is off and vice versa...

VMax2007 · May 31, 2007

Guess I should add that the truck only has 25,000 miles on it. Think the fluid would be bad this soon?

Rob

All depends on what it was used for prior to you buying it. If it was used for heavy towing without the proper aux cooling, heat will kill fluid properties exponentially faster. My 2000 I just sold to my brother was shifting poorly (racing between 1st and 2nd gears when cold) and I thought I had tranny problems coming, then I checked the fluid and it was 2 quarts low. I added 2 quarts and it is has been fine since. Not sure why it was low 2 quarts, it has never leaked?? That remains a mystery. It has 95K on it now.

KyRob · May 31, 2007

Thanks for the replies guys. The tow mode works as it should. I tried it out the other day. Not sure how the truck was treated before I got it. It was a lease turn in and was leased for nearly 2 years and then set on a lot for 8 months prior to me buying it. It had 20K on it when I got it. From all outward appearances the truck was treated very well. Reason I am wondering about this is the warranty is up in a couple months and I don't want to pay the 1500 bucks to extend it when everyone I talk to says they have had no problems with their GMC trucks and several of them have 100,000 plus miles on them. Like someone said on here the other day, the extended gives them peace of mind knowing it's there if it does tear up. That's true but a man could sure put some nice wheels and tires on for the money.

Rob

danmc00 · May 31, 2007

I have an 03 that does the same thing. I have had it checked out before and no one seems to give me an answer.

Truckman031 · May 31, 2007

The 2-3 clunk is "normal", however it should not shift that hard. You really shouldn't feel much of a shift unless you really lay into it.

Wingnut · May 31, 2007

Thanks for the replies guys. The tow mode works as it should. I tried it out the other day. Not sure how the truck was treated before I got it. It was a lease turn in and was leased for nearly 2 years and then set on a lot for 8 months prior to me buying it. It had 20K on it when I got it. From all outward appearances the truck was treated very well. Reason I am wondering about this is the warranty is up in a couple months and I don't want to pay the 1500 bucks to extend it when everyone I talk to says they have had no problems with their GMC trucks and several of them have 100,000 plus miles on them. Like someone said on here the other day, the extended gives them peace of mind knowing it's there if it does tear up. That's true but a man could sure put some nice wheels and tires on for the money.

Rob

Warranty is 1500 bucks? You can get a transmission rebuilt for less than a thousand if you look around, and especially if you jerk it out of there yourself (not as hard as people think). So if the tranny is all you're worried about, I'd say skip it.

As for the shifting issues...I'd say change the fluid and filter, and drive it like you want to. I worked my '02 Z71 pretty hard, and it never had problem one with the transmission. Most people have the same experience as I did...Hard parts don't break like they used to.

For the most part anyway

My transmission came apart at 12k miles or so (on the SS)...GM had no idea why, lots of the AWD SS's are losing their transmissions pretty quickly. But with a tune and a new tranny, it now shifts like a hammer into 2nd most of the time...Just like I want it to.

67bird · May 31, 2007

Do a search here on this. You will find that there is a TSB on the 2-3 clunk you are describing. I would recommend the warranty. I have bought one with every vehicle I have and it has paid off in the end. I recently had to take my z-71 in to have a seal replaced in the front axle. I also took my truck in for the clunk you describe as well as bad u-joints. I have owned my truck since 2004. I bought it used with 19,000 miles on it. It just turned 60,000 miles. I tow nothing with it and all it hauls is me. My warranty covered the replacement of the u-joint. It covered the yoke upgrade for the front u-joint. It also covered the pinion seal and the rear output shaft seal on the transfer case. Both times all I had to pay was a $100.00 deductible. You may also want to check to see if the dealer where you bought it offers a disappearing deductible. This is where if they (the dealership) services it you don't pay a deductible at all. One of my warranties also had a clause that if I didn't use it, the money paid for the warranty would be refunded to me.

cmoore74 · May 31, 2007

These are common issues. My '06 shifts like that from 1-2 if I go easy on the gas. I don't think the shift is too hard, but it is definitely not as smooth as the other shifts and 1-2 does shift smoother with more throttle. The hardness of the shift is obviously relative. Maybe yours is more noticable than mine.

The 2-3 clunk might be the common loose slip-yoke on the drive shaft. If you do a search you will come up with a TSB regarding replacement with a nickel plated slip yoke shaft. I've also heard it could be the u-joints as well.

I would suggest bringing it to the dealer to get it checked out before the warranty is up. If they say these are normal you at least have a record of them looking at it. If something does go after the warranty is up and is releated to the problem you brought it into the dealer for they would be more apt to fix it out of warranty as the problem is on record. I brought mine in for both of these just so it's on record.

There is a poll about extended warranties. It is very debatable if they pay for themselves. I bought them on the last 3 vehicles (2 of which were the small trucks, a 2000 blazer and a 2000 S-10 which are known POS) and not one paid for itself. If you are not mechanically inclined and plan on keeping your truck for a while it might be worth it. If I decide not to get one (leaning that direction) I will fix what I can and pay out of pocket for anything I lack the tools and/or not comfortable in repairing.