Reverse Issues

woodsmanpete · October 25, 2011

Had a fluke happen a couple of weeks ago and it has been intermittent since. Pulled into a gas station to get a cup of coffee, came out started the truck, placed the shifter in R and drifted back a few feet then .... BANG (like I just backed into something or someone hit me) , then a whining/grinding sound. Put the truck in park and got out to find out what was going on. Nothing around, nothing under the truck, nothing leaking. Sip of coffee, scratch head, get back into truck, back up drive off still scratching my head.

I have had this happen about 5 times in the last two weeks although it is mainly pulling up, stopping and then putting it in reverse to back into a parking spot or into the driveway, always stopping completely prior to shifting.

Had the mechanic at work plug in his scanner, no codes of any sort, leaving it to be mechanical, at least in my mind. Searched around in here and came up with the sun shell may be broken or cracked. Another item of note is that the 1 - 2 up shift is sometimes a very hard shift, although sometimes not. I have no other probems in any of the forward gears. The truck has 72,400 miles on it. kind of a let down, but I think it's time to let specialist look at it before I loose reverse, 2 & 4 if it is indeed the sun shell, or completely trash the transmisssion.

I don't beat the truck, spin the tires, off road. I do tow occasionally, mostly with a single axle trailer loaded with my garden tractor or mulch (never over the rated capacity).

Any thoughts, suggestions, or condolences appreciated.

Again, 2007 GMC Sierra 1500 Crew 4x4 5.3 it was BB tuned in fall '08.

Xtremski74 · October 25, 2011

Ok here's my dumb reply. Have you checked the fluid on a level surface? Smell it to see if it smell's burnt. I had something similar happen in an older 4l60e but it ended up being a servo. I had the whole tranny rebuilt. Just because they had it out anyway. Only cost $800 to rebuild then.

woodsmanpete · October 26, 2011

Ok here's my dumb reply. Have you checked the fluid on a level surface? Smell it to see if it smell's burnt. I had something similar happen in an older 4l60e but it ended up being a servo. I had the whole tranny rebuilt. Just because they had it out anyway. Only cost $800 to rebuild then.

Not a dumb reply, but yes, I had the fluid and filter changed at 55,000 and I check it often. I checked it the evening after the first incident right on the mark good color and it didn't smell burnt. Dropping the truck off tonight. I was quoted double your number by two different shops, one guy said he would swap mine for one he had on the shelf, the other said he would rebuild my transmission, so I'm going with the latter.

Thanks for the reply, I'll post what I find out.

Mossyoakglock · October 26, 2011

Is this something that would be covered by the 100,000 mile Powertrain Warranty?

woodsmanpete · October 26, 2011

Is this something that would be covered by the 100,000 mile Powertrain Warranty?

You may have just saved me, the dealer is running my vin to see exactly what the powertrain warranty is on my truck. I thought it was up at 5 yr/60,000 mi.

ETA: Thanks Mossyoakglock, the powertrain warranty is 100,000 mi, so it goes into the local dealer monday for diagnosis.

Mossyoakglock · October 26, 2011

If yours is a GMT-900 then I believe that your truck has the 5yr/100,000 powertrain warranty. Somebody correct me if I'm wrong.

marine_man · October 28, 2011

You're correct on the 5yr / 100k coverage.. when my sun shell went it was just after my 5yr term was up. GM replaced the transmission for $500 out of pocket for me with a 3 yr / 100k warranty on the transmission.

Mossyoakglock · October 28, 2011

I wasn't sure if the 5yr/100,000 powertrain warranty started on the 07 or 08 GMT-900's. I know my 08 has it but could not remember if dad's 07 had it, although it doesn't matter since he's past the 100,000 mark now.

woodsmanpete · October 28, 2011

I wasn't sure if the 5yr/100,000 powertrain warranty started on the 07 or 08 GMT-900's. I know my 08 has it but could not remember if dad's 07 had it, although it doesn't matter since he's past the 100,000 mark now.

I had edited a reply above that the truck does indeed have the 5yr/100,000 mi power train warranty. Thanks again for the heads up, I hope they honor the warranty. The truck goes in on Monday for diagnosis. As for the transmission, the banging out of reverse has become more frequent, and I am starting to see and feel problems witht the forward gears. Twice now it has become stuck in first and will not up shift until I can get to a place where it will stay in reverse a couple feet and align everything back up. After that it will run as normal until it downshifts all the way to first. Monday will not get here fast enough, one more trip home from work and then 5 miles to the dealer Monday morning. I'm anxious to get this fixed being single with only one vehicle, makes one think about keeping a beater car around for situations like this.

Thanks again.

woodsmanpete · November 3, 2011

Just picked up my truck from the dealer, broken snap ring in the transfer case which wreaked the internals of the TC. Completely rebuilt the TC, drove it 5 miles back to work and it shifts perfect.

Thanks again for the insight.