97 chevy pickup transmission issue

Reply

  #1  
Old 12-19-08, 06:09 PM
Member
Thread Starter
Join Date: Dec 2008
Location: Nebraska
Posts: 18
97 chevy pickup transmission issue

I have a 97 1/2ton chevy pickup and the transmission shifts great when i first start driving it but the farther i drive it the worse it shifts, it slams into gear. I took it to a transmission shop and they said the transmission is bad and needs to be replaced. Is this true or is something else causing this issue. If this is the problem how difficult would it be to change. I am a mechanic on airplanes just don't know much about vehicles.
 
Sponsored Links
  #2  
Old 12-19-08, 06:34 PM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,588
Possible you have the same tranny I have in my wrecker (4L80E). Periodically (although not lately, knock on wood) my input speed sensor ($50) will go bad and the symptoms are very firm shifts - slamming - especially the 1-2. It's a fail-safe limp mode just to get you down the road. Yours may or may not be having this problem. Have you tried reading codes? Tranny codes don't always illuminate the CEL, but the codes can still be read. At any rate, I think I would get a second or maybe even third opinion before I wrote off the tranny entirely.
 
  #3  
Old 12-19-08, 06:51 PM
dhamblet's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Oct 2008
Location: PAcific Northwest
Posts: 264
Changing out an automatic transmission isn't that big a deal unless it is 4wd. Then u have the transfer case to also contend with. Basicly you get the car up on jack stands, disconnect the linkage, remove the starter and drive shaft, unbolt the flywheel (flexplate) from the torque converter, unbolt the transmission from the engine and remove it. Having a transmission jack is helpful in removing it but a pile of cardboard boxes works as well to jerk it out on. Replacing it requires the use of a tranny jack.
 
  #4  
Old 12-19-08, 10:29 PM
Member
Thread Starter
Join Date: Dec 2008
Location: Nebraska
Posts: 18
yes it is a 4wd, i don't have a tranny jack, can u rent tranny jacks
 
  #5  
Old 12-19-08, 11:29 PM
dhamblet's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Oct 2008
Location: PAcific Northwest
Posts: 264
Yep, they run $10-$15/day. You'll need it with the transfer case hanging off it.
 
  #6  
Old 12-20-08, 05:43 AM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,588
You are going to seek other opinions on the condition of the tranny before you dive into this, right?
 
  #7  
Old 12-24-08, 09:26 PM
Member
Thread Starter
Join Date: Dec 2008
Location: Nebraska
Posts: 18
yes i'm going to seek other opinions first and if some could explain to me why it works great when could and not when it warms up that would be great, the tranny does not slip just slams into gear.
 
  #8  
Old 12-24-08, 11:36 PM
dhamblet's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Oct 2008
Location: PAcific Northwest
Posts: 264
O ring seals starting to wear out?

One thing you may want to try since u might have to replace it anyway is some Seafoam additive. I was amazed at the difference it made in an old Buick we had for a while. Dump some into the tranny and see what happens.
 
  #9  
Old 12-26-08, 07:00 AM
Member
Join Date: Jun 2008
Location: Eastern Georgia
Posts: 486
The input speed sensor is a PM generator, and the heat may be changing the output of the sensor causing hard shifting when it is warm.
 
  #10  
Old 12-27-08, 01:32 PM
Member
Thread Starter
Join Date: Dec 2008
Location: Nebraska
Posts: 18
I added some K&W trans-x and drove it about 250 miles over Christmas and what i noticed is that it up shifts fine and only slams when it down shifts, so i think i may change speed sensor and see if that helps. Were is the speeds sensor located and how hard would it be to change
 
  #11  
Old 12-27-08, 04:06 PM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,588
Depends on the tranny. On my 4L80E it sticks out the left side of the case not far from the linkage, I think it has one bolt holding it in place.

FWIW when my input sensor fails it only slams on upshift; I don't recall there being any noticeable downshift issues.
 
  #12  
Old 12-29-08, 11:55 AM
Member
Join Date: May 2008
Location: Central, IL.
Posts: 109
You have a 4x4 and the speed sensor is in the t-case. I seriously doubt it is the reason for your tranny issues. The VSS is only one of hte inputs the puter uses to control your tranny shift points. Engine temp, O2 readings, rpms, all affect how the puter controls engine/tranny performance.

Adding the tranny fix stuff thickened up the tranny fluid, and helps to seal some leaking seals. If this helped your tranny, then its only a temp fix. The only real fix is a rebuild.

REplacing the tranny isn't difficult if you have some mechanical skills. You should be competent enough to handle the job by yourself. Seeing as how you have a fullsize you shouldn't have to remove the exhaust system, although you will have to navigate around it. No need for a tranny jack either. Here is a quick run down.

Disconnect the battery, pull hte starter.
drop both driveshafts, some fluid will come out of the t-case.
Drop the t-case, weighs about 100 pounds, I bench press mine out, and get a buddy to help me lift it back in.
Remove the tranny cross brace, using a block of wood under the tranny pan and a floor jack lower the tranny so you can get a socket and 3' of extensions on teh top two tranny bellhousing bolts. Remove them and jack teh tranny back up.
Remove the bellhousing lower cover, post 98 you will have to remove the two plugs in teh bottom of hte tranny housing. take out the torque converter to flexplate bolts (3). spin the flexplate with a pry bar and use the edge of the trnny bellhousing as leverage. Post 98 you will have to push the prybar intot he biggest hole. You will have to go through the starter hole to unbolt the three bolts.

Disconnect the tranny cooler lines, newer versions have spring quick clips that pop off, older versions you have you use flare wrenches.
Dipstick tube will come out once the top passenger bolt is out.
Older version remove tv cable, newer version unplug electrical connector.
Watch the vacuum hoses, they run over the top of the tranny and hook to the t-case.
Disconnect the shift linkage.

Once the torque converter is unbolted, remove the remainder from the tranny bellhousing bolts. The tranny should be free and ready to be dropped out. Balance it on the floor jack and lower it. Tranny full of fluids weighs roughly 175pounds.

Longer more detailed instrcutions for the S10 version.
http://www.blazerforum.com/m_29933/tm.htm

Same tranny 700R4/4L60/4L60e.
 
  #13  
Old 01-09-09, 08:12 AM
Member
Join Date: Jul 2006
Posts: 37
I can't offer any advice on what the problem might be, but I can tell you what I did when I had a tranny problem in my 97 Chevy 3 years ago.

We have a reputable Aamco shop around here and I took it in to them for a free assessment. No strings....and an honest report on what the problem was.

I would do that again before jumping to conclusions as to what the problem MIGHT be. See if you can do the same. It won't cost you anything and if you have two or three places who will take a look at it in the area and they all say the same thing......you have your report.

That may not be practical for some guys but a tranny replacement is big money and the problems only get worse. I had to rebuild part of mine and it cost me $1,800.00 The price for a new was over $2,300.00 and the rebuild was all new stuff except for my housing. It's been 40,000 miles and over 3 years now with no new tranny problems at all.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes