Transmission Problems: Common Issues and Solutions

This thread will be an overview of some of the more common transmission issues. While there are lots of things that can and will happen, I will only discuss the 4 main ones…….yeah I know that the thumbs suck, but I didn’t want to kill any dial-up modems, just click the thumb to see the whole page.

1. LACK OF MAINTENANCE
A lot of people neglect their transmissions. The fluid and filter should be changed at least every 30,000 miles. Failure to do so, can lead to poor performance and premature death. It isn’t that hard to do yourself and doesn’t have to be done very often, so there is really no excuse for not taking proper care of your transmission. (If you don’t feel comfortable doing it yourself, it will cost much less than a new transmission to have a shop do it.) Proper maintenance will insure that you get the most out of your transmission.

2. P1870
This problem is normally noticed as hard shift between first and second gearand or an illuminated "Check Engine" or "Service Engine Soon" light. GM has issued a number of service bulletins on the subject:

http://img209.imageshack.us/img209/6875/1870info1mk.th.jpg (http://img209.imageshack.us/my.php?image=1870info1mk.jpg)

http://img192.imageshack.us/img192/6829/1870info28xp.th.jpg (http://img192.imageshack.us/my.php?image=1870info28xp.jpg)

http://img192.imageshack.us/img192/7680/1870info34bw.th.jpg (http://img192.imageshack.us/my.php?image=1870info34bw.jpg)


The most common cause of this code is the valve body:

http://img292.imageshack.us/img292/2344/1870pg12fk.th.jpg (http://img292.imageshack.us/my.php?image=1870pg12fk.jpg)

http://img235.imageshack.us/img235/8222/1870pg27cr.th.jpg (http://img235.imageshack.us/my.php?image=1870pg27cr.jpg)

http://img235.imageshack.us/img235/3674/1870pg32gp.th.jpg (http://img235.imageshack.us/my.php?image=1870pg32gp.jpg)


Here’s a picture of the valve body, that I got from a link that blazes9395 posted:

http://img235.imageshack.us/img235/8955/valvebody9ve.th.jpg (http://img235.imageshack.us/my.php?image=valvebody9ve.jpg)




3. IGNITION SWITCH FAILURE
Yes, ignition switch, that switch does much more than just make the starter go. ;) Some of the ignition switches that came on these trucks have had problems with the contacts inside. Basically anything that is controlled through the switch can be affected by its failure.

http://img150.imageshack.us/img150/342/milgaugesthird11pr.th.jpg (http://img150.imageshack.us/my.php?image=milgaugesthird11pr.jpg)

http://img150.imageshack.us/img150/4617/milgaugesthird20zc.th.jpg (http://img150.imageshack.us/my.php?image=milgaugesthird20zc.jpg)

4. REACTION SUN SHELL
With this condition you will lose reverse, second and fourth gear. The reaction sun shell is a weakness of these transmissions, unfortunately this problem requires a rebuild or replacement of the tranny.

http://img150.imageshack.us/img150/5061/reactionshell0ec.th.jpg (http://img150.imageshack.us/my.php?image=reactionshell0ec.jpg)

http://img150.imageshack.us/img150/4241/reactionshell20dw.th.jpg (http://img150.imageshack.us/my.php?image=reactionshell20dw.jpg)

http://img150.imageshack.us/img150/6372/reactionshell35tx.th.jpg (http://img150.imageshack.us/my.php?image=reactionshell35tx.jpg)

http://img150.imageshack.us/img150/2055/reactionshell45gt.th.jpg (http://img150.imageshack.us/my.php?image=reactionshell45gt.jpg)

Here's a picture of a good shell:
http://img104.exs.cx/img104/6130/sunshell24aw.jpg

Here's a picture of a broken shell:
http://img104.exs.cx/img104/2826/sunshell14zr.jpg

Here's a couple sun gears, you can see part of the broken shell on the gear on the right:
http://img104.exs.cx/img104/2921/sungear7hz.jpg


Thanks, to ImageShack for free hosting.

Excellent thread, transmission's are ridiculously complex and everytime I try to figure out how they exactly work, I go cross-eyed. :)

Don't forget about the flyplate! This contributes to transmission damage as well (unbalanced shaft isn't good for the tranny) This is mine, fortuneatly when it happened I stopped driving it

http://www.pghconsulting.net/teal/fly.jpg

Holy jebus, that was a close one.

How did you know it was about to go?

LOL, blazee, I wish you posted this about 2 months ago! I was looking for all this information when I was rebuilding my tranny, especially the component stacking, had to beg to get it from my dealership. I did do the reaction shell upgrade with a hardened unit, along with the sonnax tcc valve correction, put in a better 3-4 clutch pack, the Z-pack from raybestos just to name a few. Great post.

I got my Blazer when I was 16 and because I was a typical teenaged-boy, my rear-end and tranny got beat to hell. (power-braking, Saturday-night racing, and heavy-footed green-lights in 1st gear) So anyhow, about 5 months ago, I was driving home from school, and I started to hear a clank,clank,clank! About every revolution of the wheels, there was a "clank." Being as 'auto-stupid' as I was, I didn't do a thing. A few days later, it got louder, instantly after I dropped the pedal out of the school parking lot. I took it to my dad finally, and he said it had to be the rear end. My nieghbor, a mechanic, said the same. So, two days later, I drove it half-way to the dealership (about 7.5 miles) and then in the middle of an intersection, I was jerked forward and started to hear a very loud BANG,BANG,BANG! So, to end it short, n get to my point, I called a tow-truck, And $2800.00 later I had a new tranny, rear-end, and a knowledge (sort-of) of how to care for my tranny. I bought the truck at about 44,000miles. My tranny went out around 78,500miles. I never, NEVER even checked the fluid the entire time. This isn't what killed my tranny though. Driving it with a bad rear-end is what really did the damage. Now, if I bought a GM rebuilt tranny, do I still have to worry about these Reaction Sun Shells or Ignition Switch Failures? Or does this only apply to older Blazers (Pre-98)? I was also told to service the tranny every 15,000 miles, but you're saying 30,000. Uhhhh??? Help? Thank you in advanced for any help that you can give me!

If you are auto-illiterate, please read this and don't just skim through. It can save you some money. (No, not on car insurance )

Great job and the thumbs are awesome for my shitty dial-up connection. Thanks!!

Excellent thread, transmission's are ridiculously complex and everytime I try to figure out how they exactly work, I go cross-eyed. :)
Thanks.

http://auto.howstuffworks.com/automatic-transmission.htm

BTW... Happy Birthday

Don't forget about the flyplate! This contributes to transmission damage as well (unbalanced shaft isn't good for the tranny) This is mine, fortuneatly when it happened I stopped driving it

That looks nasty


LOL, blazee, I wish you posted this about 2 months ago! I was looking for all this information when I was rebuilding my tranny, especially the component stacking, had to beg to get it from my dealership. I did do the reaction shell upgrade with a hardened unit, along with the sonnax tcc valve correction, put in a better 3-4 clutch pack, the Z-pack from raybestos just to name a few. Great post.

Thanks. If mine goes I plan on beefing it up pretty good, too.


I got my Blazer when I was 16 and because I was a typical teenaged-boy, my rear-end and tranny got beat to hell. (power-braking, Saturday-night racing, and heavy-footed green-lights in 1st gear) So anyhow, about 5 months ago, I was driving home from school, and I started to hear a clank,clank,clank! About every revolution of the wheels, there was a "clank." Being as 'auto-stupid' as I was, I didn't do a thing. A few days later, it got louder, instantly after I dropped the pedal out of the school parking lot. I took it to my dad finally, and he said it had to be the rear end. My nieghbor, a mechanic, said the same. So, two days later, I drove it half-way to the dealership (about 7.5 miles) and then in the middle of an intersection, I was jerked forward and started to hear a very loud BANG,BANG,BANG! So, to end it short, n get to my point, I called a tow-truck, And $2800.00 later I had a new tranny, rear-end, and a knowledge (sort-of) of how to care for my tranny. I bought the truck at about 44,000miles. My tranny went out around 78,500miles. I never, NEVER even checked the fluid the entire time. This isn't what killed my tranny though. Driving it with a bad rear-end is what really did the damage. Now, if I bought a GM rebuilt tranny, do I still have to worry about these Reaction Sun Shells or Ignition Switch Failures? Or does this only apply to older Blazers (Pre-98)? I was also told to service the tranny every 15,000 miles, but you're saying 30,000. Uhhhh??? Help? Thank you in advanced for any help that you can give me!

If you are auto-illiterate, please read this and don't just skim through. It can save you some money. (No, not on car insurance )
A transmission rebuilt by GM 5 months ago should have all the updates. You could still be affected by the ignition switch failure, but I wouldn't worry too much, it isn't common for your year model. The 97 models are the one that are most affected.

The 30,000 mile change interval is the recommended time under normal conditions.

The 15,000 mile change interval is the recommended time under harsh conditions. This applies to vehicles that do alot of stop and go driving, taxis, emergency vehicles, etc.......

Great job and the thumbs are awesome for my shitty dial-up connection. Thanks!!

Thanks. Up until last month I had dial-up, I know what it's like waiting for a bunch of pics to load.

Excellent post! Keep up the good work. What a great read that was!

Excellent post! Keep up the good work. What a great read that was!
Thanks. :)

Blazee,
It looks as though my tranny busted the part that takes out reverse, 2nd and 4ht gear. It will go forward but just hums in reverse. Do you know any reputable dealers that sell rebuilt tranny's with all of the proper upgrades. I live in coastal NC. Thanks




Thanks.

http://auto.howstuffworks.com/automatic-transmission.htm

BTW... Happy Birthday



That looks nasty




Thanks. If mine goes I plan on beefing it up pretty good, too.



A transmission rebuilt by GM 5 months ago should have all the updates. You could still be affected by the ignition switch failure, but I wouldn't worry too much, it isn't common for your year model. The 97 models are the one that are most affected.

The 30,000 mile change interval is the recommended time under normal conditions.

The 15,000 mile change interval is the recommended time under harsh conditions. This applies to vehicles that do alot of stop and go driving, taxis, emergency vehicles, etc.......



Thanks. Up until last month I had dial-up, I know what it's like waiting for a bunch of pics to load.

Blazee,
It looks as though my tranny busted the part that takes out reverse, 2nd and 4ht gear. It will go forward but just hums in reverse. Do you know any reputable dealers that sell rebuilt tranny's with all of the proper upgrades. I live in coastal NC. Thanks
I'm sorry for the delayed response. I looked up transmission repair in your area, you have a lot of shops close by, including 3 GM dealers and an aamco. If you wanted one with all the GM upgrades, I would suggest checking the prices at one of the dealers. The price for rebuilt tranny at GMPartsDirect is about $1800 delivered (that includes the $350 core and a little over $200 shipping). You can probably buy a rebuilt tranny at one of your small local shops for $500 - $1000, but most likely they will not have the upgraded parts. A respectable shop would probably build you one with the upgrades that you want for less than $1500. All of those prices are considering that you do the installation yourself. If you have the dealer or aamco pull your tranny, rebuild it, and reinstall.... your probably looking at $2000 - $2500.
As far as reputable places, I don't know any of the places in your area so you would have to ask around.

Before repairing or replacing anything, I would verify that 2 and 4 are gone.

.......thought that this would be a good addition to this thread, it is part of a thread about a P1870 problem:

sad news...
I finally took the truck in to the trans shop. After going over all the options, I finally gave permission for them to drop the trans. Turns out, yes it is the valve body, but also the clutches were cooked, and 2 check balls were stuck. You could see the indent on the plate. They said it still ran well, considering everything they found. They are rebuilding it, updating w/sonnax, this afternoon. $1200. I guess I knew it was coming. Hopefully this is one less headache for us now. Just about anything else that goes wrong, we can do ourseves. But trannys are a no-no.
And, while it was up on the rack, I noticed a fresh oil leak.......I hope it's not where it appears to be..the oil pan!


This is exactly what happens to the tranny when you have a bad TCC regulator valve that is worn, which is almost always the problem with these valve bodies. This is the common sonnax part everyone talks about. The part is not that expensive, and is rather easy to install if you have the specific reamer that is required. The reamer though is expensive (Around $ 150.00)

You usually will get the common P1870 code, indicating trans component slipping, sending max line pressure to the transmission, giving you the hard 1-2, and basically slowly, yet surely destroying your transmission. Anyone who drives with the P1870 code and does nothing about it, should be prepared to rebuild their transmission, becuase it will eventually fail.

The TCC PWM solonoid can cause a harsh 1-2 shift also, but this can be checked with a scanner while test driving the truck. The scanner will verify if the PWM is within range. If its not within range, the PWM would have to be replaced. If its sending proper voltage values to the scanner, then the next thing to look at(assuming all other readings from the transmission are within spec. and no service engine light is on, is to look at the TCC valve regulator (the sonnax part).

The check balls are common, Trans-Go makes a thicker valve body plate that resists the common problem of check balls going through the valve body plate. The Trans-Go also resists the rusting, which is common on these plates also.

The clutches they are referring to usually are the 3-4 clutches. They are a very common problem, and burn up as a result of the TCC regulator wearing out in the valve body. A very advisable thing to do(especially if you plan on keeping it or if you do a lot of towing), is to upgrade the weak 3-4 clutches to something like the Raybestos Z-Pack, or Alto 9-clutch pack. They can take the higher stress in these trannies, and last a lot longer than OEM. That being said, the O.E. 3-4 clutch pack has been redesigned to take more stress than the previous ones used. In my opinion, I still don't think they are good enough.

Another good thing to do is to just replace the sun gear shell with a stronger, better built unit. Something like "the beast", or something stronger. This is a very weak point in the 4L60e.


Ask and see what they replace, and what they leave in the tranny. Some builders will replace bushings, bearings, all clutches and stuff, others will just replace whats broken. This last option is not a full rebuild, just a fix(hopefully). Either way, I hope this helps give you an idea as to whats going on.

Also, here is a link for the Sonnax TCC regulator.
http://www.transmissionspecialty.com/parts/PDF/77754-Combo(rb).pdf