K5 Blazer Forums  
Home of the 1969-91 K5 Blazer/Jimmy including GM Trucks and Suburbans.  
Go Back   CK5 Forums > General Discussion > The Garage

Remove these ads.

Reply
 
Thread Tools Display Modes
Old 05-18-2009, 07:36 AM   #1
renstyle
Registered User
 
Join Date: Mar 2007
Location: Boone, Iowa
Posts: 28

i Trader: (0 )

'91 K5 - 700R4 Tranny will not shift up, only have 1st and reverse - UPDATE: TV issue

Well finally got all of the bad fuel out of the tank. Got a '91 K5 with 350TBI. I'm still checking on the tranny type, looks like a 700R4 (it is stock).

I was able to make a short test drive about 5 mi with no problems, max speed 55MPH.

As I was heading home I tried shifting down to 3, then 2, finally 1. I was going very slow (less than 15MPH). Each shift down "felt" normal.

Now I find that no matter where I shift the tranny will not shift up out of 1st. Only pushed it to 20MPH, no more.

Shifting into reverse and 1st is fairly smooth, a slight clunk, satisfying, not scary sounding. No slipping noted when moving in either gear. The fluid at the stick looks clear and pink.

I've been waiting for a nice, dry day to get the tranny filter swapped out and new fluid. Got 5 QT of Dextron-III and a quart of Tranx-X. The guy at the shop told me you may get 5-5.5 QT of fluid swapped out, so watch the dipstick like a hawk.

I've never pulled the pan off a tranny before. I've tried cleaning the outside of the housing (no leaks) with a lint-free cloth and tried to make the rest of the pan area as clean as I can get it before I pull it off.

I've been advised to torque the nuts 20ft/lb once the pan it back on, and to make doubly sure the gasket on the old filter comes out, or use a small pick to make sure it gets removed.

Do I need to worry about the little metal ball bearings floating around in the pan? Apologies if this sounds like a dumb question.

Anything else I can check while I am down there? The shift-linkage "looks" ok, but to my inexperienced eye (and ear) I could very well be missing something.

Last edited by renstyle; 08-28-2009 at 11:41 AM.
renstyle is offline   Reply With Quote
Sponsored Links



Remove these ads.
Old 05-18-2009, 08:08 AM   #2
Fabrimacator21
Registered User
 
Join Date: Feb 2009
Location: Redding
Posts: 2,476

i Trader: (0 )

Does it feel like it's shifting when you go from 1st to D?
Fabrimacator21 is offline   Reply With Quote
Old 05-18-2009, 08:15 AM   #3
79chevyk10
Supporting Member
Let's go wheeling!
 
79chevyk10's Avatar
 
Join Date: Dec 2003
Location: Central Coast
Posts: 611

i Trader: (0 )

I understand from your above post that you are not that knowledgable about transmissions so bare with me.

I assume that during your initial test drive that it shifted into all gears at normal shift times (i.e. 1st thru 4th with TCC lockup felt). As you manually down shifted thru the gears is when the problem started? Or sometime after that?

You state that it has reverse so we can rule out a broken reaction sun shell (a commom part to break on a 700R4 that will cause no reverse, 2nd or 4th gears)

I would start by looking under the hood and make sure the TV cable is attatched to the throttle body (the cable that is below the throttle cable, as you apply throttle the TV cable with become longer opposite to the throttle cable).

Just a note here: There are two pressures that dictate when a 700R4 shifts. Throttle Valve pressure (TV pressure) and Governor pressure. As you apply throttle the cable is pulled and moves the throttle vavle cable inside the valve body increasing TV pressure. At the back of the trans there is a governor valve that is driven off the output shaft. As speed increases the governor spins faster off the output shaft. Once the governor pressure exceeds the TV pressure the 1-2 shfit valve is able to move directing pressure to the 2-4 band servo allowing a 2nd gear shift. The relationship between the TV pressure and governor pressure remains the same for all upshifts.

Make sure the TV cable is attatched. If it is, pull on it to make sure that it did not break. You should feel a "spring back" feeling when you pull on it. Make sure it doesn't feel like it is binding.

If above checks out okay, then another common cause for a 700R4 to not upshift is a broken/siezed/worn out governor.

On the pass. side towards the rear of the transmission case is a dome looking cover. Remove the cover (cover is pressed in, no clips or bolts) and pull the governor out. Look at the green plastic helical gear for wear or stripped teeth. Also check to make sure the vavle inside the governor (you can see the vavle between the windows of the governor shaft) move freely and next make sure the weights and springs at the end are not broken or missing.

If it turns out that it is neither the TV cable nor the governor, than you have internal transmission failure that will require removal and overhaul of the transmission.

Good luck

Aaron.
__________________

79' K10 350 FI/ TH350/ Triple sticked Doubler/ Locked 1 tons/ Tube chassis / 42 Pitbull's


91' Silverado K5/350TBI/700R4/NP208/Posi D44/Detroit 14FF/35's. AC blow cold, cruise works and clean interior
79chevyk10 is offline   Reply With Quote
Old 05-18-2009, 08:28 AM
Posted in reply to 79chevyk10's post starting "I understand from your above post that..."
  #4
4X4HIGH
Supporting Member
Registered User
 
4X4HIGH's Avatar
 
Join Date: Dec 2001
Location: Pleasanton, CA.
Posts: 21,503

i Trader: (20 )

GM of the month Winner
I broke the sun shell in my 700R4 and i still had reverse and 1st but no 2-4.
__________________
1989 blazer, 350/700R4/NP241, 8" lift, D60/14FF w/4.56's and Detroits, hydro assist, 35" BFG Mud
Scott
4X4HIGH is offline   Reply With Quote
Old 05-18-2009, 08:41 AM
Posted in reply to 79chevyk10's post starting "I understand from your above post that..."
  #5
scooter122983
Supporting Member
Registered User
 
scooter122983's Avatar
 
Join Date: Oct 2006
Location: Fond du Lac, WI
Posts: 296

i Trader: (0 )

One thing that wasnt discussed was adjusting the TV. To do this there is a adjuster on the bracket that holds the TV cable and throttle cable. This adjuster has a button on it. You may need a screwdriver or such to get to push this button. Push the button and slide the adjuster sleeve all the way up into the adjuster and release the button. Now go in the cab and depress the skinny pedal all the way to the floor. You should hear a a sound like a zip tie. If you dont hear that sound then you probably have a problem with your adjuster in which case you will need a new cable.
scooter122983 is offline   Reply With Quote
Old 05-18-2009, 08:43 AM
Posted in reply to 4X4HIGH's post starting "I broke the sun shell in my 700R4 and i..."
  #6
79chevyk10
Supporting Member
Let's go wheeling!
 
79chevyk10's Avatar
 
Join Date: Dec 2003
Location: Central Coast
Posts: 611

i Trader: (0 )

Quote:
Originally Posted by 4X4HIGH View Post
I broke the sun shell in my 700R4 and i still had reverse and 1st but no 2-4.
Impossible. The reactions sun shell is meshed to the rev. input drum and then splined to the reaction carrier sun gear. They always break at the splines or strip out at the splines. The 2-4 band clamps and holds the reverse input housing from spinning. It is all splined/meshed together. You lose the sun shell it is impossible to have any one of the gears.
__________________

79' K10 350 FI/ TH350/ Triple sticked Doubler/ Locked 1 tons/ Tube chassis / 42 Pitbull's


91' Silverado K5/350TBI/700R4/NP208/Posi D44/Detroit 14FF/35's. AC blow cold, cruise works and clean interior
79chevyk10 is offline   Reply With Quote
Old 05-18-2009, 09:36 AM
Posted in reply to 79chevyk10's post starting "I understand from your above post that..."
  #7
renstyle
Registered User
 
Join Date: Mar 2007
Location: Boone, Iowa
Posts: 28

i Trader: (0 )

Quote:
Originally Posted by 79chevyk10 View Post
I understand from your above post that you are not that knowledgable about transmissions so bare with me.

I assume that during your initial test drive that it shifted into all gears at normal shift times (i.e. 1st thru 4th with TCC lockup felt). As you manually down shifted thru the gears is when the problem started? Or sometime after that?
The manual downshift felt like it performed normally, each successive shift down allowed the engine to "wind up" with the corresponding lowering of intertia (dunno exactly how to explain, but it felt like a totally normal downshift). It was at this point, when I tried to shift back to (over)drive that I realized that I wasn't shifting up out of first. Took a while to get home at 7MPH!

Quote:
Originally Posted by 79chevyk10 View Post
You state that it has reverse so we can rule out a broken reaction sun shell (a commom part to break on a 700R4 that will cause no reverse, 2nd or 4th gears)
Others have mentioned the sun shell, and the fact I have reverse is a good sign!

Quote:
Originally Posted by 79chevyk10 View Post
I would start by looking under the hood and make sure the TV cable is attatched to the throttle body (the cable that is below the throttle cable, as you apply throttle the TV cable with become longer opposite to the throttle cable).
Maybe another n00b question here, but better to test this linkage with the engine running? no? doesn't matter if you're not moving?

Quote:
Originally Posted by 79chevyk10 View Post
Just a note here: There are two pressures that dictate when a 700R4 shifts. Throttle Valve pressure (TV pressure) and Governor pressure. As you apply throttle the cable is pulled and moves the throttle vavle cable inside the valve body increasing TV pressure. At the back of the trans there is a governor valve that is driven off the output shaft. As speed increases the governor spins faster off the output shaft. Once the governor pressure exceeds the TV pressure the 1-2 shfit valve is able to move directing pressure to the 2-4 band servo allowing a 2nd gear shift. The relationship between the TV pressure and governor pressure remains the same for all upshifts.
Quote:
Originally Posted by 79chevyk10 View Post
Make sure the TV cable is attatched. If it is, pull on it to make sure that it did not break. You should feel a "spring back" feeling when you pull on it. Make sure it doesn't feel like it is binding.
I will assume again this test should be done at the throttle body connection under the hood? This should be obvious once I roll back under the truck, the other end of the cable prolly just runs into the tranny...

Quote:
Originally Posted by 79chevyk10 View Post
If above checks out okay, then another common cause for a 700R4 to not upshift is a broken/siezed/worn out governor.

On the pass. side towards the rear of the transmission case is a dome looking cover. Remove the cover (cover is pressed in, no clips or bolts) and pull the governor out. Look at the green plastic helical gear for wear or stripped teeth. Also check to make sure the vavle inside the governor (you can see the vavle between the windows of the governor shaft) move freely and next make sure the weights and springs at the end are not broken or missing.
This again I assume will be more evident when I remove the cover. Never having seen an actual governor (tho I do have some idea of how it works), I'll check for those weights and springs. Would taking a pic with the cover off and posting help to diagnose here?

Quote:
Originally Posted by 79chevyk10 View Post
If it turns out that it is neither the TV cable nor the governor, than you have internal transmission failure that will require removal and overhaul of the transmission.

Good luck

Aaron.
Thanks for all of the great suggestions! Very clear and concise. Would you recommend I hold off on the fluid/filter change until after checking all of this or does it matter? I've already bought the supplies and can eat the $30.00 I paid for it all even if the tranny is bunk.
renstyle is offline   Reply With Quote
Old 05-18-2009, 09:40 AM
Posted in reply to scooter122983's post starting "One thing that wasnt discussed was..."
  #8
renstyle
Registered User
 
Join Date: Mar 2007
Location: Boone, Iowa
Posts: 28

i Trader: (0 )

Quote:
Originally Posted by scooter122983 View Post
One thing that wasnt discussed was adjusting the TV. To do this there is a adjuster on the bracket that holds the TV cable and throttle cable. This adjuster has a button on it. You may need a screwdriver or such to get to push this button. Push the button and slide the adjuster sleeve all the way up into the adjuster and release the button. Now go in the cab and depress the skinny pedal all the way to the floor. You should hear a a sound like a zip tie. If you dont hear that sound then you probably have a problem with your adjuster in which case you will need a new cable.
Thanks for the tip! If all of this goes south would you have a good rec for a replacement tranny in the central Iowa area? As much as I'd love to try a rebuild myself I certainly am not up to to the task in the near future.

I'd be willing to consider swapping the tranny myself if I can find a good replacement. Got somebody to give me a hand and some experience with a swap. What does a used (prolly untested?) 700R4 go for these days? I'm hoping not much more than 500-600. Just need to get this truck moving more than anything else right now.
renstyle is offline   Reply With Quote
Old 05-18-2009, 10:11 AM
Posted in reply to renstyle's post starting "Thanks for the tip! If all of this..."
  #9
scooter122983
Supporting Member
Registered User
 
scooter122983's Avatar
 
Join Date: Oct 2006
Location: Fond du Lac, WI
Posts: 296

i Trader: (0 )

Unfortunately im new to IA. I moved here in Dec 07 and dint get back into the offroad world until this Feb. You could try Smittys in Des Moines. A guy at work got a Chrysler 12 bolt for a 02 Dodge for about $700.
scooter122983 is offline   Reply With Quote
Old 05-18-2009, 10:18 AM
Posted in reply to scooter122983's post starting "Unfortunately im new to IA. I moved..."
  #10
renstyle
Registered User
 
Join Date: Mar 2007
Location: Boone, Iowa
Posts: 28

i Trader: (0 )

Quote:
Originally Posted by scooter122983 View Post
Unfortunately im new to IA. I moved here in Dec 07 and dint get back into the offroad world until this Feb. You could try Smittys in Des Moines. A guy at work got a Chrysler 12 bolt for a 02 Dodge for about $700.
Just called Smittys, they have a trans from an '88 C1500 with 160,000 miles on it for $400. At least it gives me a baseline.

Thanks again!
renstyle is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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

Forum Jump


All times are GMT -7. The time now is 04:56 PM.


Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.