Torque convertor bolts

[chipper]

I read where several members have checked the tightness/replaced the bolts that hold the torque convertor to the flex plate.How did you tackle this job, was a lift rack used? How much time did the job take? I looked at it & seems very difficult laying under the truck.
Any & all help appreciated.

mrgene@att.net

[dmaxalliTech]

access to the bolts is through the starter hole, starter has to be removed to do this. could be a bit awkward on the ground

[WillowCreekStable]

Ummmm, should this keep me awake tonight? :rolleyes:

This is a new one to me, is it a silent killer like high blood pressure? Any symptoms to watch for? Clearly, loose bolts would be a bad thing.....

[dmaxalliTech]

willow, there have been a few issues with these bolts coming loose, you will notice a ticking sound from bell housing area. usually only one makes it all the way out, extreme cases it wollers out the holes in the flexplate. I would stick with the 'ol adage here, if it aint broke.......
Unless your in for an afternoon under the truck that is, while your there, might as well put new bolts in.

[chipper]

DmaxalliTech,
Do you know approximately how much shop time this would be at the dealer?

[WillowCreekStable]

Thanks, I was being a bit factious there. It

[dmaxalliTech]

Chipper, I would have to guess it to be in the 1.5 hour range. I will check the books tomarrow and post published time.

Thats a good q' willow. I will have to dig into that and follow up. The bolts have gone through two part no changes and are now on the third, I think they are aware of the problem or they would not change the bolts. If they are ever removed, they MUST be replaced.

[Lone Eagle]

Sounds like they must have nyloc inserts in the threads. Maybe the first ones didn't. I haven't heard of this problem since the first 01 came out. As I remember, they came loose from the factory. Later! Lone Eagle

[chipper]

DmaxalliTech,
you were going to check the "books" & let me know the time to change the T.C. bolts??

[DieselBunny]

I guess great minds think alike..... I was just at my Allison dealer an hour ago picking up a filter and this very subject came up. The service manager said it took his guy's about 2 hours to do the job. I'm going to do it my self over the week-end. Kieth was very good about giving a few photocopies from the service manual so I have a better idea of what I'm up against also gave me the replacement bolts that Allison had put out for this TSB. There is allready some sort of thread locker on the bolts in the bag. I understand that the bolts from factory are T-50 Torx, so I'll have to go out and grab one of thse puppies.
Just a word of caution about working though the starter hole.... you would'nt want to drop a socket or one of the bolts inside the bellhousing.... that would make for a looong night..:)

---->Kevin

[dmaxalliTech]

Chipper, sorry I took so long. Actual labor time would be dependent on the dealer but I would not pay more then two labor hours. If you were at my dealer, Your paperwork would say "ticking noise from back of engine area" and you would be getting six new bolts!.

[Diesel Dragon]

DmaxalliTech

The ticking sound that you describe with the loose TC bolts does it sound like an exaust pipe thats warming up and you here that tinny metal expanding sound. If it is I think mines loose too and I barely have 1,200 miles. Hmmmm I guess I'll have to investigate a little more this weekend.

Later Diesel Dragon :cool:

[chipper]

Dmaxalli,
Thanks for the help, much appreciated. smile.gif

[dmaxalliTech]

Dragon, please dont get paranoid over this! Typically the sound you will hear will change in gear and is very noticable. You might be expieriencing the famous 'tick' which is normal.

If you do drop a bolt or socket, you might be able to retrieve it through the tin covers on the bottom side of the bell housing. I just keep a small pocket magnet handy and havent had any problems.

[77TransAm]

IF you decide to try this and drop a bolt, you're probably screwed... once in a while a dropped bolt will stay up high enough to get a magnet onto, but more often than that it will drop behind the flexplate. Then you get to pull the trans, pull the flexplate, get the bolt out, and reinstall everything.

dmaxalliTech, the covers are on the torque converter side of the flexplate and a dropped bolt will fall on the engine side. It's really no fun trying to retrieve one!

DieselBunny, the GM bolts have an internal allen head (I've never seen a torx), and it is 8mm (but 5/16 will work, too). Except for the very early units, the bolts also have an external 15mm hex head, so a regular socket will work just fine.

[VANBC2500HDDA]

At about 20,000 kms my truck blew tranny fluid all over the underside of the truck and the front of my ski boat...

The dealership said that 2 of the bolts were missing, 2 were loose and 1 tight one stress fractured the torque converter and split it open...

So it does happen.

[AB_DURAMAX]

I am also one of the few that have had problems with the TC bolts backing out ....Kind of frustrating but the dealer fixed it up very quickly. Haven't had another problem since.

[saywhat]

Looks like the problem has been on 2001 models,has there been any confirmed cases on 2002 models?

[chipper]

saywhat,
All the info I have gotten off this forum indicates the problem was mainly the 01. I learned trying to get the dealer to fix it before it "blows" is impossible.2 dealers turned me down under warranty.O'well, do it myself & now know which dealers to stay away from in the future.

[AnTKoch]

I also had a bolt fall out and the rest were loose just last week and tranny fluid all over the place in my '01 I have 55,000 miles but soon after I also had a bearing go in the Allison don't know if it was related but it was expensive

[77TransAm]

AnTKoch, from your description in this thread and the other one where you mentioned the problem, I would guess that your pump bushing was the collateral damage after the torque converter bolts came loose. Once the converter loses the clamp load to the flexplate, it can wobble around a bit. This will often cause one of the lugs to crack at the weld, which shows up as a leak. At the same time, since the back end of the converter is spinning inside the pump bushing the wobbling motion will usually ruin that bushing as well. The bushing is serviceable separately, so parts shouldn't be a problem. Hopefully ATS used new converter bolts with some kind of vibra-seal or patch-lock compound on them so you don't have that problem again.

[Choreboy]

Sometimes after I have stopped my tranny makes the truck lurch forward. It happens almost immediatly after the truck stops. This is not caused by a surge in the engine. The truck is idling when this happens.

Could this be a torque converter problem? If so I need to get to the dealer fast as I have 35,700 miles on my truck. My truck was built in March of 01.

[Idle_Chatter]

Choreboy, that's the "harsh downshift to first" that has a TSB and TCM reflash to resolve. I had the same problem and the reflash solved it. First couple of times that it happened at a red light, I thought that the car behind me had tagged me in the rear! Got reflashed at 22,000, now at 53,000 and no problem!

[Choreboy]

Thanks, Tom
I will have my dealer look into it.

How often does this occur? Is it random? My truck will do it every once in a great while.

Thanks again,
Danny

[Idle_Chatter]

It's random, maybe once out of every ten or so stops. Basically, the trans programming is a little "uncertain" when to downshift to first. It seemed to happen most to me when I was slowly rolling to a stop at a light. Since the brakes weren't on hard and the truck was rolling forward, it would try to stay in second. When the program decided to finally go to first, the brakes weren't on very hard and the drop to first would make the truck lurch. Remember that our Maxes, like all diesels, have a goodly chunk of their torque produced even at idle. In addition to solving the lurch, the reflash also smoothed out some other low speed issues that you may have noticed when slowing down and reaccelerating at the top or bottom of an incline.