Author Topic: TV linkage for mid '70s Q-jet  (Read 12868 times)

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #15 on: April 07, 2017, 07:59:02 AM »
Probably best to get a gauge, usually 2nd gear starts are caused by line pressure being too high at minimum TV. Do you know if the cable is adjusted right? Is it tight at WOT?

It is tight at WOT. Even with the TV cable disconnected, it still starts in 2nd. I can always manually select 1st from a stop, but then it refuses to upshift whenever over 25% throttle. I can let completely off the gas, then sometimes it upshifts.

Offline 77cruiser

  • Qjet Hero
  • *****
  • Posts: 625
Re: TV linkage for mid '70s Q-jet
« Reply #16 on: April 07, 2017, 01:26:32 PM »
Did the trans shop that installed it rebuild it? Usually trans shops, unless they've done a lot of 200-4r's mess them up.
Jim

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #17 on: April 08, 2017, 04:55:16 PM »
Probably best to get a gauge, usually 2nd gear starts are caused by line pressure being too high at minimum TV. Do you know if the cable is adjusted right? Is it tight at WOT?

The cable is tight at WOT.  The transmission starts in 2nd even with the TV cable disconnected, as I found out when driving home from the trans shop last Monday.  I got a bracket from TCI for the TV cable, and now it drives as before, downshifting by itself when necessary, but still starts in 2nd, lock-up is hit and miss, won't upshift unless I completely let off the gas.  I'm sure it will be a great tranny when it is correct!   Trans shop inisists I get the proper baseplate/linkage alignment before they will do any more.  Good news is I have not paid them for the transmission or the  2400 stall yet, so I'm not out that ~$2k . If I fix it myself, there will be some negotiatiing on that price for sure, since they said they could do this conversion no problem.

My thoughts are it is an internal valve body issue, or a problem with the TV spring in the valve body.  The shop said they rebuilt this transmission.  They have been around for 30+ years, that's why I trusted them to do this.  They did install 3.55 gears with an Auborn limited slip differential in my BOP differential, and that works perfectly, and I paid them for that.  It was a package deal, replace my peg-leg 2.52 gears with that and do install the 2004R to replace the Powerglide. 


Grrrr, getting frustrated since this started last November.

Offline 77cruiser

  • Qjet Hero
  • *****
  • Posts: 625
Re: TV linkage for mid '70s Q-jet
« Reply #18 on: April 08, 2017, 06:27:42 PM »
Had a similar experience about 15 yrs. ago, had a shop with 30+ years exp. Had him build one for me & if wouldn't even hold a stock 305, so I studied up & did one myself & haven't looked back. It was good till the cheap conv. I bought from the first guy Fragged kept with & the one I have now is behind a 530 hp 421 sbc so far so good.

http://www.ckperformance.com/View/GM-2004R-TECHNICAL-MANUAL

Good book if you are interested in having a go at it.
Jim

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #19 on: April 10, 2017, 05:54:06 PM »
Thanks 77cruiser.  I'm gettting a 1" spacer, so I will know I have the exact pull on the TV cable.  It isn't quite right, it pulls at a slight angle instead of a direct line.  The spacer will allow a correct pull.  Then, I may install a pressure gauge to see what pressures I have in each gear.  From what I've learned, anything over 85-90 in D or OD will not allow a 1st gear start.

I really think I have four problems:  Won't unlock the torque converter sometimes, starts in 2nd always, won't upshift from 1st sometimes. Also won't lock the convertor sometimes. I know it will be fun when it's right!

Offline 77cruiser

  • Qjet Hero
  • *****
  • Posts: 625
Re: TV linkage for mid '70s Q-jet
« Reply #20 on: April 11, 2017, 08:25:20 AM »
If you haven't checked in here do so, lots of 200-4r info.

http://www.turbobuick.com/forums/transmission-talk.12/
Jim

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #21 on: April 11, 2017, 05:34:12 PM »
Thanks Jim.  I checked out some at that forum but didn't find my problem there, yet. 

I have a pressure gauge hooked up, seems like I have too much pressure at idle.  It's 115psi, never lower, in P, N, OD, and D.  From most sources, that high pressure will not allow a 1st gear start, unless the trans has been modified for it.  That's why I say most sources.  I do have instant pressure rise when I touch the gas, so the adjustment on the TV cable should be close.  With the cable connected, at ~1500 the pressures are up about 10 psi. 

I read somewhere that if the pressure isn't lower than at least 90, it won't allow 1st gear starts.  A check they said was to put it into neutral after a drive, then OD or D, and see if it starts in 1st.  Mine will that way, but won't upshift out of 1st!  Then next stop, starts in 2nd again then will upshift to 3rd, then sometimes 4th.  Lock-up is a crap shoot. 

I'm getting a carb spacer so I can be sure my geometry is perfect.  If I can't with the spacer, then I'm changing the base plate, then I'll either go back to my original trans place or get a second opinion.  I'm sure the connected pressure gauge will help. 

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5418
Re: TV linkage for mid '70s Q-jet
« Reply #22 on: April 12, 2017, 03:15:30 AM »
What method or methods are you using to get lock-up?

The TCC system is completely independent of the TV valve and everything else related to transmission function.

The factory used several different methods to utilize the TCC as you will find various different wiring diagrams for the valve body and LU solenoid. 

Is this a "retrofit" into an older vehicle?.....Cliff

Offline 77cruiser

  • Qjet Hero
  • *****
  • Posts: 625
Re: TV linkage for mid '70s Q-jet
« Reply #23 on: April 12, 2017, 05:16:41 AM »
Try to find out what he put in for a shift kit & what else is done to it. Did you check pressure @ max TV?
Jim

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #24 on: April 12, 2017, 04:19:01 PM »
Cliff, the lock-up is purely mechanical.  No wires.  It probably should unlock when the trans downshifts to first, but since it never does, I suspect that's part of its problem.  Yes, it is a retrofit, into my '68 Le Mans with a 400 Pontiac.  I'm more concerned with the shifting right now, trying to get that right, before I worry too much about the LU. 

Jim, full stroke on the TV cable at about 1500 RPM equals 265-270 psi.  I don't know what type of shift kit they used, I asked for something very firm.  The 2 or 3 times it has worked normally shifting, I'm pretty sure the firmness I want will be there, just don't know positively since the only somewhat reliable way to get it to upshift is by letting off the gas to allow the shift.  Absolutley will not upshift over more than 25% throttle. 

1" 4-hole spacer for my dual plane intake should arrive tomorrow or the next day, then the pull on the TV cable will be a perfect straight pull, no slight angle.  Really don't think it will make any difference (except to cool the carb/fuel some and maybe a small bump in torque), but I'm going to be sure it is all perfect before I take it back to the trans shop.  Can't wait for this to shift correctly!

Offline 77cruiser

  • Qjet Hero
  • *****
  • Posts: 625
Re: TV linkage for mid '70s Q-jet
« Reply #25 on: April 12, 2017, 07:19:27 PM »
The high pressure at min. TV could probably be fixed with a different pressure regulator spring. The no 1-2 could be dirt in the shift valve or another valve, or something else.
The lockup thing has me puzzled though the solenoid had the have power to it.
Jim

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5418
Re: TV linkage for mid '70s Q-jet
« Reply #26 on: April 14, 2017, 02:05:43 AM »
I don't know how the TCC could be employed mechanically either?

At a minimum the LU solenoid should have 12v supply and be grounded on a 4th gear pressure switch.  At least you wouldn't have it coming it at a stop light and killing the engine, and it wouldn't lock-up till 4th gear.

I suspect that you have much bigger troubles here than just the TV cable geometry after reading the entire thread......Cliff

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #27 on: April 15, 2017, 03:20:14 AM »
I agree about bigger problems with the tranny.  I'm just making absolutely sure the TV cable is right so they can quit blaming that.  I told the shop exactly what I wanted before they did any work, they positively assured me they can handle the job.

Offline Too Fast

  • Garage guy
  • **
  • Posts: 38
Re: TV linkage for mid '70s Q-jet
« Reply #28 on: July 08, 2017, 03:08:24 PM »
Wanted to update anyone who sees this.  Finally got the transmission back July 7th, after giving the trans shop another go at it.  It is finally fixed!  They admitted to a mish-mash of valve bodies and separator plates in the tranny.  Now it works as it should, always starts in 1st gear and upshifts/downshifts as it should.  Torque converter locks in 3rd and OD, strictly mechanical.  The shift isn't as firm as I'd like, but for now I'll take it.  I connected the TV cable to a stud I drilled on the carb linkage, with a detailed diagram I found on the web and here.

Also, since they had the car for a 6 week period last fall, then another 3 weeks this spring, and now for about 9 weeks, he gave it to me all at no charge for my inconvenience, mild stall converter included.   

Glad to have my Le Mans back for the (rest) of the summer ;D