GMC Truck Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I have a 2005 GMC Savana 2500 and have to have my 4th flexplate installed Before 90K miles. GMC and the dealership told me to Pound sand and they will not honor any warrenty or resposibility. I know this isn,t normal as I am not an idiot and used to build motors and trans on occation in my younger Days. I was thinking of ordering a beefyer plate fron jegs or summit but want some feedback from the guys who know ( that would be you) The truck has the 4.8 L but not sure how to find out what the trans is. Any help will be appriciated. I don,t want to do this myself but have a feeling I will have to. Does the trans need to be bulled out or can I slide the plate up from the bottom and bolt it on without pulling the trans? Thanks for your input.
 

·
Registered
Joined
·
2,580 Posts
Trans has to be at least pulled back enough to get to the bolts
 

·
Registered
Joined
·
519 Posts
A 4.8L with too much torque, dont hear that too often! lol
 

·
Registered
Joined
·
9 Posts
Discussion Starter #4
Torque my ass. This thing was screwed up since I bought it new. A tranny guy said he it my situation once before and that the back of the block was not shaved square and there is alway pressure on the plate because the motor bolts up crooked to the trans. At any rate I need to find out what the trans is in the truck. Where would the numbers for the trans be? The flexplates crack between the bolts on the other 3 so I imagine this one will be the same. Thanks.
 

·
Registered
Joined
·
729 Posts
who has been replacing the flexplates ? that's sad if you've had the repair done more than once. After the first failure whoever did the work should have investigated and found the root cause. flex plates simply don't break, something else is wrong which causes it to break. Using a beefier flex plate isn't going to solve the problem, you have something else out of whack putting stress on the flex plate and if the flex plate becomes stronger then whatever is now the weakest part will then break.
you want to look into things like crank shaft end play, crank shaft and flex plate runout when installed, torque converter ballooning putting pressure on the flex plate, runout on the transmission input shaft, misalignment of trans to motor. all that should have been checked and measured after the first flex plate breaking.

you said 2005 savana 2500, that's a 3/4 ton and has the 4L80e transmission. At least that's what rockauto and autozone shows for that year/model with 4.8L motor.

http://www.motor.com/article.asp?article_ID=2092
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
The gmc dealership replaced at 30K miles and again at 54K. Now it is broken again at 88K and they tell me nothing is wrong and it is normal wear. I called the main gm offices several times and talked to people who don,t what a flexplate is only to tell me there will be no warrenty or help. The dealship said that I carry too much weight. Talking to idiots at gm and getting nowhere leaves me where I am at now. The dealership accually tried to sell me another van. I dont carry too much weight which would not matter anyway but to find someone at gm with a clue is impossible. I am a guy working out of my van so $25K for Another p.o.s. is absurd. I just want to get a few more years out of this van so I can feed my kids. I just not sure if I should put in Another gm flywheel FP# 12551367 that I may get 20K miles if lucky, or go aftermarket and risk breaking something else. I not sure which poison to choose. Thanks.
 

·
00silvy
Joined
·
3,679 Posts
Weird problem. What do you mean by breaking them? Bending? Cracking in half? Cracking teeth off? I don't think a beefier flex plate will solve why it's breaking.
The trans has to be separated from the motor. Slide the trans back or the motor forward, your choice. Before you do that you have to remove the starter and unbolt the torque converter bolts. If it's a 4l60e there should be 3 of them. Should be 6 flex plate bolts. Fairly simple, just a lot of work.
 

·
Registered
Joined
·
729 Posts
if your location is southwest Florida, I seriously doubt you have a weight problem especially since there's no hills. your case is a classic example of loser dealer mechanics doing the least amount of work under warranty to get the vehicle rolling out the door. they didn't fix the root cause of the problem, and a competent transmission shop should be able to pinpoint that rather quickly based on how the flex plate cracked and some simple measuring of things. suggest you google "torque converter ballooning" and ask independent transmission shops about the problem you're having. if a licensed repair shop finds and documents the cause of your flex plate breaking, you have decent legal ground to file a claim against the dealership for improper repair work and never having fixed your problem correctly and getting reimbursed. it's all easier said than done, and you'll have to front the money out of pocket to get the thing fixed initially.

http://www.motor.com/article.asp?article_ID=901

other than what's described in the article, one other likely cause of flex plates breaking is if you rev the motor in netural then drop it into drive and the trans slams into gear. this can put excessive fluid pressure into the torque converter causing it to press against the flex plate and break it.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #9
Thanks, but I stopped doing neutral slams when the driveshaft of my 74 impala was bouncing of the floor boards back in 85. How can I tell if it is a 4L80e trans like Ron7000 thinks or the 4160 e trans. Another thing I didn,t mention that I thought was f#¤%ed up is that the trans dipstick was always popped up and would not stay in the tube. I thought the rubber seal by the lift handle was bad but it did it since day one. To much pressure building up inside the trans? The flexplate always cracks between the 5 or 6 bolt holes and last one came out in 2 pieces. Another way to go is to try to contact someone at gm that knows what the are talking about and gives a s¤¤t about customer service and loyalty. Any phone numbers will help me out greatly. I never owned a Ford worth a lick but am thinking about it because of this disaster. Please help, I hate Ford.
 

·
00silvy
Joined
·
3,679 Posts
Well if tq converter has 3 bolts it's a 60e. If it has 5 or 6 it's an 80e. I can't remember how many they have. Should also say on side of trans.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #11
Thanks. Does anyone Think the dipstick never being set in the tube all the way indicates something going on in the trans?
 

·
Registered
Joined
·
729 Posts
http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/366028-4l60e-4l80e.html

http://www.garagejournal.com/forum/showthread.php?t=98109

guys there says 4L60e has 16 bolts holding the trans pan on and it's a square pan, the 4L80e has 17 and is more rectangular. I don't know if it's true. Try googling "4L60e 4L80e difference"

the dipstick constantly popping out indicates a pressure build up inside the transmission crankcase. what would cause this i don't know exactly, i'm not a trans expert. maybe a clogged breather vent. but the crankcase pressure in the trans is completely different from the fluid circuits that feed transmission fluid from the pump in the torque converter and through the valve body to the clutches. having a few psi of pressure inside the transmission crankcase would be normal as it heats up, and if the dipstick sits loose in the tube it may be simply normal that it pops up from vibration after running a bit and the trans heating up.

the other thing i know is fluid pressure in the torque converter is sometimes highest, or can be very high, when in reverse. based on your problem happening every 20+ thousand miles or fairly seldom my guess is the cause has something to do with reverse. if it were happening when in drive which you use everyday all the time i would think you would be breaking flex plates much more often.

... like i said, you need to stop at a few trans shops and state your problem. they will probably know the cause. And they can put a pressure gauge on external ports on the transmission and measure fluid circuit pressure when in 1st, 2nd, 3rd... and reverse and confirm the problem. there is a diagnostic procedure to figure all this out and they will know. the dealer probably never did any of this, only replaced the flex plate and pushed the truck out the door. my guess is the problem lies in the valve body causing excessive fluid pressure under certain conditions, resulting in the torque converter ballooning and cracking the flex plate.
http://atp-inc.com/techbulletin/TechBulletin0903.aspx
http://www.agcoauto.com/content/news/p2_articleid/220
 

·
Registered
Joined
·
9 Posts
Discussion Starter #13
That sounds right to me as well. Now I have to convince an "expert" at GM to agree. I will look into trying to find a good trans shop but its hard to find anyone who is good at 1 thing. Everyone says they are good at everything down here it seems. I have been in SW FL for 23 years and am a plumber. I am a damn good one too. I built motors in the 80,s Mopar big blocks and 350 Chevys. I don,t claim to be a mechanic but I seem to know more than the people I talk to. I also suck at carpentry so I am smart enough not to call myself a cabinet builder. Wish me luck.
 

·
Registered
Joined
·
1,684 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #15
It is a 80E. I am bringing it to a tranny guy in town thats good and tell him to do what he has to do. I cant afford a breakdown or a new van. I thank you all for your help. Even after talking to GM and the dealer about what I thought was wrong and all your input they still told me to go f"##k myself. I guess I should not have expected a " thanks for the bailout" from GM for the sweat of people like us.
 

·
Registered
Joined
·
2 Posts
I have a 2005 GMC Savana 2500 and have to have my 4th flexplate installed Before 90K miles. GMC and the dealership told me to Pound sand and they will not honor any warrenty or resposibility. I know this isn,t normal as I am not an idiot and used to build motors and trans on occation in my younger Days. I was thinking of ordering a beefyer plate fron jegs or summit but want some feedback from the guys who know ( that would be you) The truck has the 4.8 L but not sure how to find out what the trans is. Any help will be appriciated. I don,t want to do this myself but have a feeling I will have to. Does the trans need to be bulled out or can I slide the plate up from the bottom and bolt it on without pulling the trans? Thanks for your input.
 

·
Registered
Joined
·
2 Posts
Had the same problem with my 99 GMC Savanna. After the second replacement they also told me to pound sand. So I put my thinking cap on and found that the distributor cap was collecting moisture causing a crossfiring on startup chamged the cap and rotor and dried out the distributor, and the problem was gone. Eventually, I changed out the distributor a precaution.
 
1 - 17 of 17 Posts
Top