Shifting issues with a 700r4

[MDc10]

Has anyone else had an issue when changing from a th350 to a 700r4 with the shifting. Ever since I changed trannys I haven't been able to shift past overdrive. When you make the switch are you suppost to lengthen the linkage? Does anyone have the answer? Its like the shifter bottoms out on OD, I haven't been able to take it down to 1 or 2. I would really appreciate if someone could answer this question for me. Thanks in advance.
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[INSIDIOUS '86]

You change the shift gate in your column. A th350 column has ably three gear grooves. 700r4 column has four.
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[MDc10]

Originally Posted by INSIDIOUS '86

You change the shift gate in your column. A th350 column has ably three gear grooves. 700r4 column has four.
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No I didn't know I.needed to. To be honest with you im not really to sure what your talking about when you.say shift gate. Where can I get one and what do they run?
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[INSIDIOUS '86]

It's the gate inside the column that gives your column shifter it's pattern. You can either completely diss assemble you column or put in the O/D column.
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[gmclowsierra]

The column has no shift gate. It gets its detents from the trans. You probably are having a shift linkage problem. I would look at the length of your shift linkage.
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[INSIDIOUS '86]

Originally Posted by gmclowsierra

The column has no shift gate. It gets its detents from the trans. You probably are having a shift linkage problem. I would look at the length of your shift linkage.
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It does. You think it holds itself with magic?
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[gmclowsierra]

Ok your right. When you have half the experience with these and any other trucks ill listen to what you think. Obviously you have no clue on what your talking about. If you unhook the linkage at the trans the shifter will move freely without any detents.
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[1LowToy]

Sounds like the linkage is wrong to me. Either adjustment or your linkage rod to the trans is the wrong length. Oh ccheck for anything that would be opstructing the linkage too. Please admit defeat and let us know what you find.

As for the clicking between gears thats the trans. However the column will have detents so that you will have to pull the shift lever towards the driver to move from park to reverse, pull towards you to move the shifter from neutral to reverse or park. As for having 4 positions for forward gears I hope there is enough range or movement available in the column. Maybe someone could chime in that has had this experience. For mine I just got the OD shift indicator to swap out. If there is more I'm sure we would all like to know.

[MDc10]

Originally Posted by 1LowToy

Sounds like the linkage is wrong to me. Either adjustment or your linkage rod to the trans is the wrong length. Oh ccheck for anything that would be opstructing the linkage too. Please admit defeat and let us know what you find.

As for the clicking between gears thats the trans. However the column will have detents so that you will have to pull the shift lever towards the driver to move from park to reverse, pull towards you to move the shifter from neutral to reverse or park. As for having 4 positions for forward gears I hope there is enough range or movement available in the column. Maybe someone could chime in that has had this experience. For mine I just got the OD shift indicator to swap out. If there is more I'm sure we would all like to know.

ok that being said how would I go about lenghthening the linkage, to be honest I've never done it. Can I weld a rod the same diameter as the linkage to give it length or what. Is there a standard for this procedure or what? I appreciate you guys help.
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[1LowToy]

I'd measure what you have and snag one from the wrecking yard. I have one for mine (somewhere) as I had parted out a truck that had the 700r4 for my future swap. I have no idea if they are different lenght or not. I've heard that the crossmembers are different so I kept that of the parted truck too. There is a torque converter lockup switch and the proper throttle pressure cable setup too. Make sure you have that setup correctly too.

Let us know what you come up with.

[MDc10]

Originally Posted by 1LowToy

I'd measure what you have and snag one from the wrecking yard. I have one for mine (somewhere) as I had parted out a truck that had the 700r4 for my future swap. I have no idea if they are different lenght or not. I've heard that the crossmembers are different so I kept that of the parted truck too. There is a torque converter lockup switch and the proper throttle pressure cable setup too. Make sure you have that setup correctly too.

Let us know what you come up with.

I've hooked up the lock up switch, but what are you talking about when you say pressure switch? I figure my linkage is too short, just because when you shift it feels like it's bottomed.out in OD.
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[MDc10]

Alright fellows I.finally figured out what it was,(had some help from a tranny builder) he said it was the detents. Said I needed to change the column to an of
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[kalbert]

You don't need to change out the whole column, just get the right gate for the lever from something with a 700 like Insidious said earlier.

The rooster on the shift shaft inside the transmission has detents on it That's what holds the transmission in gear.

The gate in the column is what lets the lever move the full range, also with detents which provide the means to prevent accidental shifts from high gear to neutral etc. without pulling back on the lever. Generaly there's a notch for park, reverse, neutral, and forward gears. Sometimes the pin on the lever that engages in the gate is so worn you just about don't have to pull the lever back before moving it from forward to reverse, etc.

The problem you're having is the gate in the column does not have notches in the right places to allow a full range of motion for the lever to be able to select every position. The rooster on the 350 has different spacing than on the 700, and the 700 has one more notch. Generally when you have a 350 gate and a 700 transmission no matter how you adjust the linkage you can either not get park or not get 1st and the reverse/neutral doesn't line up quite right.

[MDc10]

[QUOTE=kalbert;5790946]You don't need to change out the whole column, just get the right gate for the lever from something with a 700 like Insidious es the right places to allow a full range of motion for the lever to be able to select every

When you say shift gate, where is this located in the cab or.under the hood? Cause if it's in the cab that's not the problem. Under the hood where the linkage hooks to the column there's a collar with a split ring holding the collar on the column and when I shift down as far as I can it bottoms out on the collar. So if the shift gate is in the cab that's not the problem. Also shouldn't the "gauge" have the OD indicator on it? Mine does so theoretically there should be enough notches if it has a OD on the column, correct?
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[beamn7]

Even if you don't have enough range of motion, you should still be able to obtain P, R, N, OD, D, 2 as long as it is adjusted properly. Don't pay attention to the indicator when adjusting as you may need to adjust that as well. Disconnect the linkage at the trans when in Park (be sure the parking brake is on) move the connection on the trans by hand 2 clicks so that the transmission is now in Neutral. Back in the cab, while holding slight forward pressure (towards the windshield) on the shifter move it slowly down allowing it to walk over the gate in the column for "R". As soon as you are able to move it back forward towards the dash.... stop. You will notice that you will not be able to move it back up now without pulling back. That means you are in what would be "N". Have a buddy hold the shifter in that position and now go under the truck and reconnect the linkage adjusting it to line up. Once you have done that your buddy can let go of the shifter as it should not move now.
Remove the small lower portion of the dash bezel just below the column (4 screws) and on the column will see a clip with a wire / string attached to it. Move it up or down on the colmun to align the shift indicator with "N".

It should work properly after this point unless the shift rod is too short. At that point you can either lengthen the shift rod or obtain one from the junkyard for a 700r4 truck....

EDIT: Did some research and looks like the MD8 (700r4), M40 (THM 400) and MV4 (THM 350) trans all use the same rod. GM # 6271387. (An old number at that..........) MT1 (4L80E) used 15614394 (R/V series)

Hope this helps.

[1LowToy]

Review this post on the t350 to 700r4 swap. (see item 7)

http://transmissioncenter.net/700R4_Swap_Info.htm

Sounds to me like you need the check the range of motion on the tranny it self. Second thought. Will this tranny shift into low range (1st) gear and stay there? If so this may be just you shift indicator stuck.

Nice info for me since I have a factory carb on a 250 I6 I should be able to bolt up my 700r4 once I get it built without mods to the carb like the others. (See item 5)

[MDc10]

I'll give that a try when I get home this evening and see if I can get it to work. Thanks for the help.
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[kalbert]

If your truck was originally a 700, and someone swapped in a 350, then you put a 700 in you could have any combination of parts now and it's hard to say what might be there.

If you're certain the gate in the column is correct, another area to look at would be the bracket the rod connects to the shift shaft on the transmission. There are several variations between cars, trucks, vans, chassis, transmissions, etc. They all look pretty much the same but the flats where they line up on the shift shaft will clock them at different positions making it difficult or impossible to connect or adjust the linkage to get full range.

[Greenlee]

It seems odd to me that people are saying there are shift gates in the column. I had mine apart not too long ago and I could have sworn that the shifter moved freely until I hooked up the linkage to the transmission.
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[kalbert]

Originally Posted by Greenlee

It seems odd to me that people are saying there are shift gates in the column. I had mine apart not too long ago and I could have sworn that the shifter moved freely until I hooked up the linkage to the transmission.
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The rooster on the shift shaft inside the transmission is what gives you the positive positions when you move the lever.

The gate inside the column is what the end of the shift lever engages in. It is what makes you have to pull the lever toward you before shifting from park, reverse, and neutral. It prevents bumping or moving the lever from forward to reverse without first pulling it toward you. The forward gears usually are in a block together and can be selected without pulling on the lever. The end of the shift lever wears out or breaks off, as do the notches in the gate, and the spring that pushes the end of the lever into the notches in the gate. Its possible yours is worn and moves freely without pulling back, I've had some that were pretty loose.
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