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Jetaway 315 tv rod adjustment help


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hi Guys, as you may know i have had my super hydromatic ( jetaway 315) in the 64 Bonneville rebuilt and i have an issue with it slipping when it tries to shift from first to second while in D selection. my trans builder thinks its the Throttle valve rod from the carb that needs adjusting but i have read the chassis shop manual on the issue and it goes on about fitting a tool but does not show any pictures of it or really how to do the adjustment.

 has any one out there mastered this adjustment and can help me out with advise on what to do ? 

 i think the trans guy is correct as when i take my foot off the gas pedal it will drop into 4th, and you have to remember my 64 was in a frontal smash, the rod will most certainly need adjusting as the whole motor jumped clean out of its mounts and was stopped from shooting out through the radiator by the cross member hooking on the sump !!!

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https://www.jalopyjournal.com/forum/threads/please-explain-cad-jet-away-hydramatic-kickdown-operation.599420/

Start with this: there's some discussion (and confusion) re TV rod and something else called a throttle pressure rod. You'll have to get her up on the hoist and make sure those cables (or rods) are properly connected and into their proper factory brackets. It sounds like road testing & fine tuning after each subsequent test is the way to go. Good luck!

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20220307_165854.jpg

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1 hour ago, Fitzy said:

https://www.jalopyjournal.com/forum/threads/please-explain-cad-jet-away-hydramatic-kickdown-operation.599420/

Start with this: there's some discussion (and confusion) re TV rod and something else called a throttle pressure rod. You'll have to get her up on the hoist and make sure those cables (or rods) are properly connected and into their proper factory brackets. It sounds like road testing & fine tuning after each subsequent test is the way to go. Good luck!

haaha funny that mate!!! i read this one today !!

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14 hours ago, 64 kiwi boni said:

hi Guys, as you may know i have had my super hydromatic ( jetaway 315) in the 64 Bonneville rebuilt and i have an issue with it slipping when it tries to shift from first to second while in D selection. my trans builder thinks its the Throttle valve rod from the carb that needs adjusting but i have read the chassis shop manual on the issue and it goes on about fitting a tool but does not show any pictures of it or really how to do the adjustment.

 has any one out there mastered this adjustment and can help me out with advise on what to do ? 

 i think the trans guy is correct as when i take my foot off the gas pedal it will drop into 4th, and you have to remember my 64 was in a frontal smash, the rod will most certainly need adjusting as the whole motor jumped clean out of its mounts and was stopped from shooting out through the radiator by the cross member hooking on the sump !!!

Kiwi, presumably we’re talking about the same thing, there is a cable that attaches to the carburetor left side linkage. This runs to the tranny, but don’t confuse it with the gas linkage. This cable adjust the shift pattern of the tranny. The shorter you make the cable adjustment, the harder and later the shift. The longer the cable adjustment the earlier and softer the shift. This is to a degree the mechanical version of a vacuum modulator. Do not confuse this with a kick down cable. This cable will usually have a center wire that moves in a sleeve, like a choke cable. Changing the length of the center wire is the adjustment. There are many arrangements and variations of this cable and how it’s adjusted so I don’t know what exactly yours is, but I have no doubt you’ll be able to see how yours is done.

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16 hours ago, Last Indian said:

Kiwi, presumably we’re talking about the same thing, there is a cable that attaches to the carburetor left side linkage. This runs to the tranny, but don’t confuse it with the gas linkage. This cable adjust the shift pattern of the tranny. The shorter you make the cable adjustment, the harder and later the shift. The longer the cable adjustment the earlier and softer the shift. This is to a degree the mechanical version of a vacuum modulator. Do not confuse this with a kick down cable. This cable will usually have a center wire that moves in a sleeve, like a choke cable. Changing the length of the center wire is the adjustment. There are many arrangements and variations of this cable and how it’s adjusted so I don’t know what exactly yours is, but I have no doubt you’ll be able to see how yours is done.

yes mate its the rod system on my 64, and that rod is linked at the carb and actuates a lever on the side of the trans 

it has adjustment sleeves but i am really finding it hard to get good information on how to adjust it..

my trans guy says, go drive the car adjust it and work from there as to lengthen or shorting  the rods action

the pontiac shop manual is really hard to get your head around as it talks about using a special tool.

i will keep googling and see if i can find an answer.... the problem with hunting through forums is there is soooo much not quiet right information!! or they are talking about caddy super hydromatics or buick jetaways and each has its own different tv rod system ..i am not finding a lot about pontiac jetaway transmissioins... guess we are special aye!!!!:rofl:

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11 hours ago, 64 kiwi boni said:

yes mate its the rod system on my 64, and that rod is linked at the carb and actuates a lever on the side of the trans 

it has adjustment sleeves but i am really finding it hard to get good information on how to adjust it..

my trans guy says, go drive the car adjust it and work from there as to lengthen or shorting  the rods action

the pontiac shop manual is really hard to get your head around as it talks about using a special tool.

i will keep googling and see if i can find an answer.... the problem with hunting through forums is there is soooo much not quiet right information!! or they are talking about caddy super hydromatics or buick jetaways and each has its own different tv rod system ..i am not finding a lot about pontiac jetaway transmissioins... guess we are special aye!!!!:rofl:

Can you take a few pics of the setup at the tranny & couple at the carb? That said, I would say you need to lengthen the cable. By what you described the cable is short enough that the mechanism sees hard throttle, so it holds in gear, I.E. doesn’t upshift. Lifting your foot relaxes the mechanism allowing an upshift. So by lengthening the cable you reduce the tension on the mechanism. This will allow an earlier upshift.

This is how a vacuum modulator works. It sees Venturi vacuum when you accelerate. There are vacuum set points that trigger a upshift, but if you press down more on the accelerator you change the input signal, vacuum, which then holds the tranny in gear longer. Likewise if you lift your foot off the pedal some it will cause the tranny to upshift earlier.

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22 hours ago, Last Indian said:

Can you take a few pics of the setup at the tranny & couple at the carb? That said, I would say you need to lengthen the cable. By what you described the cable is short enough that the mechanism sees hard throttle, so it holds in gear, I.E. doesn’t upshift. Lifting your foot relaxes the mechanism allowing an upshift. So by lengthening the cable you reduce the tension on the mechanism. This will allow an earlier upshift.

This is how a vacuum modulator works. It sees Venturi vacuum when you accelerate. There are vacuum set points that trigger a upshift, but if you press down more on the accelerator you change the input signal, vacuum, which then holds the tranny in gear longer. Likewise if you lift your foot off the pedal some it will cause the tranny to upshift earlier.

i will get her on the hoist on the weekend Last indian and take some pictures..👍

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  • 2 weeks later...
Posted (edited)

So today i got time to have a go at adjusting the TV rod i have attached a picture of the shop manual instructions on how to adjust it.

at first they are really hard to understand but if you do one part at a time and understand what the heck they are talking about terminology wise, you will be away laughing.

here is the rod aka the tv rod

 D0EB699A-82B7-4E2D-BE2D-1756CDE39A46.jpeg

it unclips and can be adjusted

BA4B3147-CE15-474A-BE4D-A82A9007DA30.jpeg

i measured mine so i had a reference point.... and after mucking around with lenghts and test drives x5 i ended up in the same place i started !!!!😡

9263555A-F925-4906-9230-DA5A6D0B58D1.jpeg

the manual calls for a pin to be located in the pivot arm and thats where you lock it to make the adjustments with not only the rod to the carb in the picture above BUT also the vertical rod coming up from the transmission, this pivot point is NOT equal so there is a ratio involved here.

i followed the instructions and test drove the car....   

74785269-1EF5-4EE2-8179-C963BF144AB4.jpeg

554A4C22-A3CE-445B-BFB2-12E204C62711.jpeg

the car shifts from 1st to 2nd then slips trying to bite third... you lift you foot off the gas and slowly you can hear it bite and its in 4th not 3rd!!! a wtf moment !

if you stop and just boot the gas it launches clean, you can feel 1-2 shift then it revs way out and wont engage 3rd.

if you stop and just drive off with a light push of the gas pedal ... same result

when i first drove the car today( cold Trans) it was the same so its got nothing to do with the cold oil bypass valve.

so now that i have tried the "as per factory" adjustments i went 10mm each way on the vertical tv rod adjustment and sadly, no difference except  i lost the kick down that i had at the factory setting.

 if i manually shift the car from L to S it slips and if i then shift to D no difference, still slips and the more power i put into it, the more it slips.

i will be seeing Bill the trans guy on Friday afternoon and i will be explaining what i have done. 

Edited by 64 kiwi boni
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Good luck buddy

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1 hour ago, Fitzy said:

Kiwi - I've lost track because it has been some time, but is there any vacuum involved with your auto? I'm going to assume that mechanical linkages take care of shifting & kickdown duties, in your case. The only reason I mention it is that once we discovered that my brake booster had a vacuum leak, now that it's fixed that SHOULD sort the shifting problem I had with my trans - being that the vacuum modulator runs off the same vacuum line as the booster. I'll find out tomorrow if it made any difference. Anyway, it really threw me and I'm mentioning it just in case some tiny sneaky little vacuum leak may be causing you problems.

no mate ! super hydros dont use vacuum . it is this rod from the carb to the trans that basically does the same job of regulating the oil pressure and doing the kick down too!.

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I don’t believe the shift down adjustment rod is your problem. If you disconnect it, it should still drive great except it won’t do a fast downshift on big acceleration. The more you tighten the rod nut, on the rod coming up vertically, the earlier it will shift into 2nd on hard acceleration. Again, If it was too tight(shortened) it will shift into an easier, higher rpm gear. So if you disconnect it or loosen the nut almost all the way off it will not shift out of 4th into second or 3rd with pedal to the metal. I think there is another issue causing your trans problem. I noticed the two I had rebuilt shifted hard from 2nd to 3rd but never ever slipped. As i rack up a 2000 miles it shift better. The only problem is the trans oil will drain from the converter overnight causing a decent warmup to start driving right. It is a known issue I guess.

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Posted (edited)

Thank you Del ! 

Thats exacly what is happening 

I shorten the vertical rod and I lose the down shift 

if I put the rod back to exactly where is was... every close to the factory setting 

I get my down shift again 

what is happening is 3 rd is not engaging and the trans slips 

I take my foot out of it 

it goes straight into drive and I can then put my foot down again 

I do think he has something wrong in the valve body 

and he’s coming to my place next Sunday (bill the trans guy that is )

and I bet we will be putting it in the hoist  and pulling the valve body

👍

he did give me a written warranty and has been very good about it so fingers crossed he can fix the issue 

Edited by 64 kiwi boni
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Hope he stands behind his work and makes it right. BUT didn't you take the trans in to him?  So he's not on the hook for install and adjusting.

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1 hour ago, 64 kiwi boni said:

Thank you Del ! 

Thats exacly what is happening 

I shorten the vertical rod and I lose the down shift 

if I put the rod back to exactly where is was... every close to the factory setting 

I get my down shift again 

what is happening is 3 rd is not engaging and the trans slips 

I take my foot out of it 

it goes straight into drive and I can then put my foot down again 

I do think he has something wrong in the valve body 

and he’s coming to my place next Sunday (bill the trans guy that is )

and I bet we will be putting it in the hoist  and pulling the valve body

👍

he did give me a written warranty and has been very good about it so fingers crossed he can fix the issue 

Yeah it’s not the kick down! Either a valve body issue or, if I read everything right, that the tranny never shifts into 3rd? Is that right?  If so the builder left out a clutch plate or friction plate.

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2 hours ago, Last Indian said:

Yeah it’s not the kick down! Either a valve body issue or, if I read everything right, that the tranny never shifts into 3rd? Is that right?  If so the builder left out a clutch plate or friction plate.

thats the strange thing Last Indian, the trans worked correctly BEFORE the rebuild it was justA leaking oil majorly.

when i first drove it after the rebuild 3rd was there, now its not. its got to be shit in there or a sticking valve....  

4 hours ago, JUSTA6 said:

Hope he stands behind his work and makes it right. BUT didn't you take the trans in to him?  So he's not on the hook for install and adjusting.

yes he seam to be standing by his work mate, now i have been worrying that i didnt flush the cooler and lines properly! 

but i think i am over thinking it again!!! 

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On a side note, I’ve had several people tell me they drove the 64 Bonneville over 120mph back when they came out.

Edited by Bonneville convertable64
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2 minutes ago, Bonneville convertable64 said:

On a side note, I’ve had several people tell me they drove the 64 Bonneville over 120mph back when they came out.

i would believe that mate, but good luck doing 120 on a new zealand road!!! haaha :rofl:

hay how are the twins? have you done any new upgrades ?

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13 hours ago, 64 kiwi boni said:

thats the strange thing Last Indian, the trans worked correctly BEFORE the rebuild it was justA leaking oil majorly.

when i first drove it after the rebuild 3rd was there, now its not. its got to be shit in there or a sticking valve....  

could be a valve body issue as I said, but the slippage makes me think friction plates. Why? Usually a valve piston is either applied or not! But if what you describe is slippage, that tends to be clutch plates! So he could have left out a steel or fiber plate. He could have not installed a piston seal correctly or missed it altogether. He could have done something wrong with the piston springs. All of these would cause slippage.

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3 hours ago, Last Indian said:

could be a valve body issue as I said, but the slippage makes me think friction plates. Why? Usually a valve piston is either applied or not! But if what you describe is slippage, that tends to be clutch plates! So he could have left out a steel or fiber plate. He could have not installed a piston seal correctly or missed it altogether. He could have done something wrong with the piston springs. All of these would cause slippage.

Thank you last Indian ... it will be interesting to see what it is next weekend 👍

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37 minutes ago, 64 kiwi boni said:

Thank you last Indian ... it will be interesting to see what it is next weekend 👍

I guess I should refine that statement a little better. When I say a piston seal not installed properly or left out, I mean for the clutch pack of 3rd gear. The same applies for the spring comment. You may very well know this, but if not, there is a large diameter piston, 5” or so, in each clutch pack. These pistons a have a seal around them that seals them to the clutch pack housing. These pistons operate much in the same way a brake piston operates. Pressure is applied to the piston which in turn squeezes the clutch pack together. A clutch pack is an assembly of alternating steel plates & fiber plates. The fluid in between them creates the adhesion between them when the piston applies pressure to them. If the fluid is burnt the fluid losses it’s additives that create adhesion and the plates can slip. If the fiber plates are worn there can become clearance between the plates that allow slippage. So the same would hold true if a single fiber plate were left out or an incorrect clearance issue between the plates and their respective interface components existed.

Edited by Last Indian
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Very good information last Indian 

when we get to that point I will be asking the questions on what’s going wrong with the 3 rd  gear clutch pack 

ijusta hope I don’t see crap in the pan 

or I have failed ! 

My trans cooler is part of the radiator (factory) and was rebuilt by my radiator mate 2 years ago 

the oil lines to and from that cooler are brand new along with the 4 sections of hose connecting these lines to the trans and radiator 

One thing I do remember about the trans before it was rebuilt was it had a sharp shift into 3 rd way sharper than the 1-2 or the 3-4 shift 

 

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  • 2 weeks later...

so a update here, my transmission guy arrived back with the valve body and reinstalled it and everything working and shifting like it should.

so clearly the issue was in the valve body, yet the guy said he had added a ball bearing that helps with the 2-3 shift. i am not sure that was all that was the issue but, he was true to his word and fixed it free of charge . this i really appreciated considering how much i paid for him to rebuild it.

 

 

AND it was a Sunday along with it being his 77th Birthday !!  Bill really enjoyed our"test" drive as the 64 ran super smooth on the road and is very quiet! 

The sun was out and justA nice day to be cruising :cheers:

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