I have a '97 S10 Blazer 2 door, AT, 4x4 with 166k miles. I replaced tranny at 100k with a brand new GM tranny. Now all of a sudden the truck has no forward gears but reverse works perfectly fine. I performed a filter/fluid change after 30k and 60k on this tranny. Anyone have any ideas? Thanks!

Have you been keeping an eye on the fluid level? Even with a new transmission you can still have leaks.
Other than that I don't know

Has your tranny slipped at all? Have you ever heard a clang when putting it in any gear. It could be your sun shell reaction gear or valve body. Has your SES light show on your dash. Does it register any codes in your computer. If so, please post them. Lets take it from there. Has your truck made any noise or act
in any abnormal way?
SC

Thanks for the quick replies. It was a new GM tranny replaced by the dealer 66k miles ago. I am 10 months past the warranty. I check tranny fluid level on a regular basis as well as maintain the truck well. Other than this the truck runs very good and is in great shape. There are no codes tripped, no leaks, and the fluid right now is showing on the dipstick (although I can't properly check it since I can't warm up the transmission.) There were no clunks, noises, or slipping whatsoever before this. The only problem I saw was when I did a fluid/filter change a couple months ago I saw a very small, thin, curved piece of metal in the pan. It was about 3/8" long and 1/16" wide. I obviously know this isn't good but I needed to get the truck back together asap. Any additional ideas would be greatly appreciated. Thanks!

I think you answered your own question....it sounds like you have an internal problem. Either way, with metal that size being found, you have to pull it and tear it down to see what went. I hate to break the bad news, but it sounds like thats your only bet at this point.

Sorry to hear that it happened, and in all reality it shouldn't have on a transmission that is so new.

I wouldn't bother seeing the dealer over it since it's past the warranty.
Aftermarket transmission shops will install all the updates that the dealer might omit so the problem hopefully won't happen again.

1997 ignition switch can cause an improperly working transmission.

Thanks again guys! Yeah, it sounds bad. I'll remove it this weekend. I wish I had a lift. :crying:

BlazerLT, very interesting about the ignition switch. Do you have any more info on this? I did have a problem with my ignition switch for a while intermittently. Sometimes when turning the key forward, it wouldn't start and no light would light up on the dash. I would have to shake the key a little and try a few times for it to start. Then one day it just was fine from then on.

Someone I work with had problems with his '96 and after a rebuild he noticed just a slight slipping. After some investigation he found a technical service bulliton that listed a missing ground wire to the tranny. They checked it out and sure enough it was missing the ground wire in the harness. GM sent a new harness and that fixed the problem...still great after 6 years.

I got a new GM tranny a few years ago because I go it at dealer cost and because of the warranty. Unfortunately I just past the warranty.

Thanks!

Yea, I just installed the ground update on my 1995, I was having a flaring 1-2 hift and since the upgrade, it has been smooth as silk.

As for the ignition switch, I am not talking about the key tumbler. There is a black module in the steering colum that will have a bad connection on a 1997.

It can cause:

- Fuel pump priming issues
- Misfiring issues
- Transmission issues
- False sensor issues

I just don't want to send you on a wild goose chase. It is a 1997 and the switch is the weakness for your year. When it goes, it can really screw things up and have people looking elsewhere and costing them 1000s.

Seeing you have been having some problems with it lately, you might want to swap it out. Your transmission is electronically controlled. And if there is some electronic issues, it can possible be the cause.

Also check your PCM harness to make sure it is plugged in firmly just in case. Just unplug the connectors and replug them in with the battery disconnected.

Tranny's out! Not too bad even without a lift. I borrowed a tranny jack and got some larger jack stands. It took much of the day. The bolts for the Y-pipe were very tough! The tranny pan had a bunch of metal filings in it and a few larger chunks of metal. The fluid was loaded with a fine metal silt and was very dark in color.

BlazerLT, How do I know if I need the ground update? What is done to accomplish this? I asked my dealer but they couldn't find any TSB's on it. I got a new ignition switch just in case itr was causing any more problems.

I think there is definitely something outside the tranny that is killing them. I shouldn't be on my third transmission already. This is getting frustrating and very costly.

Thanks again!

Tranny's out! Not too bad even without a lift. I borrowed a tranny jack and got some larger jack stands. It took much of the day. The bolts for the Y-pipe were very tough! The tranny pan had a bunch of metal filings in it and a few larger chunks of metal. The fluid was loaded with a fine metal silt and was very dark in color.

BlazerLT, How do I know if I need the ground update? What is done to accomplish this? I asked my dealer but they couldn't find any TSB's on it. I got a new ignition switch just in case itr was causing any more problems.

I think there is definitely something outside the tranny that is killing them. I shouldn't be on my third transmission already. This is getting frustrating and very costly.

Thanks again!

This sounds like a major failure.

You might want to get your tranny cooler checked for a coolant leak.

That is how mine died.

This sounds like a major failure.

You might want to get your tranny cooler checked for a coolant leak.

That is how mine died.

Yeah, and with all that metal , the cooler and lines should be flushed really well before installing the new tranny...... might even want to replace them.

It looks like a grenade exploded in it. Does anyone have any info on the transmission ground problem and how to figure out if I have it?

The ground has nothing to do with it.

Something has caused a major failure.

I agree with the fact that it had major problem. But I figured it was easier to check the wiring while the tranny was out.

Hypothetically if I had the flaring problem, after 66k miles it would probably blow up in some way. I'm not sure which damage it would do if gone unrepaired though.

Thanks for the help.

If you have a first gear or second gear clutch gone, yes, it could have caused it.

You have to find out what failed though and only a tranny shop will be able to do that for you.

The ground strap problem everyone is refering too is done under the hood, so you can go ahead and fix what you have to fix on the tranny and install it again. When your taking the old tranny apart, if you have a hard part failure e.g. sunshell, any gear(s) etc that is not caused by a coolant leak( unless its a big leak and contaminating the fluid so much it loses it lubricating properties). If your clutches are toast, then I would be looking at a internal coolant leak, which is usually found in the rad, the tranny cooler would be the problem if this was the case. I will look and find the instruction sheet that came with the ground strap kit, and try to post them on here, to give you, or anybody else, an idea what it is. It took me twenty minutes to install it, and I didn't need any special tools, just some patience.

If you are installing the tranny yourself, which by the sounds of it you are, you must flush the cooler and lines like some have been saying here. I used the tranny flush bottle the hooks up to your cooler line and it did a good job. I followed that up with a small amount of tranny fluid i pumped in with a drill pump, to get anything that was remaining in there. This is imortant, don't forget to do this.

Just to be safe, I would install a new rad in there.

There has to be a reason why you are loosing trannys this frequently.

Coolant damage is one of the major causes of these phantom failures along with the tranny shop reusing worn parts or not using the hardened upgraded sunshell.

That and a lot of people not waiting until the truck is stopped before switch from reverse to drive or vice versa.

This is good info, thanks. The problem was definitely caused by a overheating. The tranny guy said that a bearing seized inside and tore everything up. He is repairing it with all upgrades and the hardened sunshell. Probably caused by some kind of blockage in the cooler or lines. I'm thinking about just putting a separate trans cooler in instead of taking any chances with the radiator even though it's only a couple months old. I'll try to flush it anyway to see if anything comes out. I'm picking the tranny up tonight and hopefully installing tomorrow.

The stock cooler in the rad should be completely sufficient for cooling any transmission properly unless you tow large trailers.

I would look into a possible blockage.

How old is the rad on it?

I picked up the trans last night and some of the gears were toast. I flushed the cooler (rad is 2 months old) with 2 cans of Kooler Kleen and then compressed air. All clean now and seems to flow out fine. After install I'll keep an eye on trans temp to make sure it's all ok.

I would update the ground as we talked about earlier for the tranny just to make sure the tranny is getting the proper signals it needs for proper shifting.

Also, yours is a 1997, so plan on replacing the ignition switch sometime within the near future.

Ever had any starting problems?

Tranny is in. All seems ok. I have had starting problems before and have the ignition switch which I'll swap in a few days.

Any luck finding those ground strap instuctions? Is it a kit or just a procedure? I just want to be thorough on this.

Thanks!

Yeah, I have found the instructions at home. When I get a chance a little later on, when I get home, I will scan and post them on here.

Tranny is in. All seems ok. I have had starting problems before and have the ignition switch which I'll swap in a few days.

Any luck finding those ground strap instuctions? Is it a kit or just a procedure? I just want to be thorough on this.

Thanks!

You have to buy the kit at the dealer, it will come complete with the instructions.

There was a thread I made lately about my experience with it.

Do a search for transmission TSB.

Alright, sorry for the delay. I have the information here for the kit, I don't know how to get it on here. The Service Kit part # is 12167310. It states that you need the Terminal Removal Tool GM # 12122523. I didn't need it to make it work, so thats up to anyone who does this update. I paid $52.80 CAD for the kit - what a ripoff. thats about it. The kit includes all the instructions with all the pictures and stuff.

Alright, sorry for the delay. I have the information here for the kit, I don't know how to get it on here. The Service Kit part # is 12167310. It states that you need the Terminal Removal Tool GM # 12122523. I didn't need it to make it work, so thats up to anyone who does this update. I paid $52.80 CAD for the kit - what a ripoff. thats about it. The kit includes all the instructions with all the pictures and stuff.

yea, it is a ripoff for a wire.

I just paid the dealer an hour to swap it in.

By looking at the instructions I know I was in for a treat.

CDN$80 well spent in my mind.