what makes it bump between gear selections

[JointTech]

I dont really have to pull back on the shift lever to get out of park and I can barely fell any bump when moving between gears.
nontilt automatic column shift th400.
any ideas?
I found one thread but it sortof ended without a good answer on the bumps being on the plate or in the tranny.
http://67-72chevytrucks.com/vboard/s...d.php?t=469765

[SS Tim]

Best thing to do is start with the adjustments. Condition of the linkage is also a concern. But the primary load you are working against is a leaf spring loaded roller on the manual shift linkage comb. It is internal to the trans. Good news is that if you really wanted more tension it is servicable by dropping the pan. Being able to shift without a pull back indicates an adjustment issue that needs to be addressed. Pick up or download a factory service manual and review the adjustments. First is the shift tube (Section 9) then the manual linkage (section 7) then the indicator (Section 9). After this the neutral safety switch might need adjustment as well (Section 12).

[JointTech]

should that have been replaced/repaired during a rebuild?
Ill fiddle with all the linkages outside the trans tomorrow.

[SS Tim]

The roller/spring is not really a wear item. I'd suspect there is simply a fair amount of wear and slop in your shift linkage making it loose and giving it inertia as you select gears.

Fiddling is not likely to correct the shift issues there is a very specific clearance on the shift tube and that is the first adjustment. Like I said read the adjustments and check them. Don't assume you can gloss over the steps and expect it to work like new.

Besides is a free download.`
http://67-72chevytrucks.com/vboard/s...d.php?t=558016

[JointTech]

what!!!>??? no fiddling?
I had the service manual but not the overhaul. tons more info in there. thanks.

[JointTech]

Automatic Transmission
1. Place the shift tube lever in "Neutral" or "Drive".
2. Loosen adjusting ring clamp screws and rotate the
shift tube adjusting ring to obtain .33" to .36" cle a rance
between the shift tube lever and adjusting ring
(fig. 7).
3. Tighten the adjusting ring clamp screws to 70 in. lbs.

MANUAL LINKAGE
Manual linkage adjustment and the associated neutral
safety switch are important from a safety standpoint.
The neutral safety switch should be adjusted so that the
engine will s ta rt in the Park and Neutral positions only.
With the selector lever in the Park position, the parking
pawl should freely engage and prevent the vehicle
from rolling. The pointer on the indicator quadrant should line up properly with the range indicators in all
ranges.

ill give it a shot tomorrow. NSS I have covered. been there..

[LockDoc]

Originally Posted by JointTech

I dont really have to pull back on the shift lever to get out of park and I can barely fell any bump when moving between gears.
nontilt automatic column shift th400.
any ideas?
I found one thread but it sortof ended without a good answer on the bumps being on the plate or in the tranny.
http://67-72chevytrucks.com/vboard/s...d.php?t=469765

Read through this thread.

http://67-72chevytrucks.com/vboard/s...d.php?t=555640

I bet your shift lever tube is stuck in the "up" position and if you spray some penetrating oil (not WD40) in around the shift lever in the cab and some at the bottom of the shift tube under the hood it will free it up. Read the whole thread and follow the instructions in post #15, in the link I posted...

LockDoc

[JointTech]

lock doc you had it with the stuck lever. I hosed it down with PB blaster and I can feel the detents and it locks in P and wont go from N to R without pulling back. so thats good!! I sprayed the actual shift tube (why do they call it a tube? its a lever and its not even round) and pulled the steering wheel apart down to the upper bearing and hosed down the inside of the column.

While it was soaking I went to the chevy dealer to see about getting a new upper bearing but they didnt have one.

So my next task was the indicator is way out of whack to the left.


I started by trying to set the adjustment on the adjusting ring.


When set to the proper clearance the detents "feel" correct but the indicator on the column doesnt change.

I tried loosening the nuts above the adjusting color but theres no adjustment to the peice that has the stops.

I loosened everything on those pic and tried to twist the collar the shift lever is attached to but that doesnt move.

Then i somehow torqued my back and had to hobble back home. lol. I need to go with somebody else to move the shift lever while I watch what happens to the pieces under the hood.

It also looks like my linkage has been cut and spliced back together.


for posterity..

loosen the blots pointed to in red. Spin the collar and the part pointed to in green goes in and out limiting the amount of travel the shift tube can make up and down. Spin it to far and you cant get out of park.

[LockDoc]

Originally Posted by JointTech

lock doc you had it with the stuck lever. I hosed it down with PB blaster and I can feel the detents and it locks in P and wont go from N to R without pulling back. so thats good!! I sprayed the actual shift tube (why do they call it a tube? its a lever and its not even round) and pulled the steering wheel apart down to the upper bearing and hosed down the inside of the column.

The shift tube is a tube, and it is round. It runs almost the full length of the column (see arrow in picture). The shifter lever connects to the top and the flat arm connects to the bottom.

So my next task was the indicator is way out of whack to the left.

Did you do this, also in post #15??

"After you have done that open the hood and loosen the adjustment bolt at the top of the rod that connects the transmission and the shifter arm on the steering column, crawl under the truck and manually shift the transmission into Park. Hold it in Park while someone puts the shift lever in the park position up above, then tighten the adjuster bolt back up. This should correct your problem."

Be sure and block your wheels before you start this.

LockDoc

[SS Tim]

Think you problem is out of order adjustments.
Shift tube to spec.
Manual linkage to spec.
Then the indicator.
Finally check NSS and adjust as required.

[JointTech]

i did that but didnt have a second person to help. But even with the linkage bolt loose moving the shfit lever doesnt "fix" it being off. Its like the actual detent peice needs to move. But I loosened all those peices and couldnt make it move any.

I feel like if the peice I call the detent since I dont even see it at all in the service manual pointed to in green would move it would fix the indicator.





im still going through the service manual trying to find where it talks about indicator adjustment.

[LockDoc]

Originally Posted by JointTech

i did that but didnt have a second person to help. But even with the linkage bolt loose moving the shfit lever doesnt "fix" it being off. Its like the actual detent peice needs to move. But I loosened all those peices and couldnt make it move any.

I feel like if the peice I call the detent since I dont even see it at all in the service manual pointed to in green would move it would fix the indicator.


im still going through the service manual trying to find where it talks about indicator adjustment.

OK, did you check to see if the indicator housing (behind the lense) was straight with the column? Sometimes they are broken or installed incorrectly and sit crooked.

Where does the indicator sit when the transmission is in Neutral?

LockDoc

[JointTech]

The indicator looks straight but I'm going to check it again tomorrow. When I had everything out yesterday I didnt see a way to move that but I wasnt really looking at the time.

Why doesnt your picture have the detent thing to keep you from pulling into reverse or out of park?

[LockDoc]

Originally Posted by JointTech

The indicator looks straight but I'm going to check it again tomorrow. When I had everything out yesterday I didnt see a way to move that but I wasnt really looking at the time.

Why doesnt your picture have the detent thing to keep you from pulling into reverse or out of park?

I added this to my earlier post..

"Where does the indicator sit when the transmission is in Neutral?"

I just found that picture on the net because it showed the tube clearly...

LockDoc

[JointTech]

it sits close to R when its in N.

[LockDoc]

Originally Posted by JointTech

it sits close to R when its in N.

Then I still think using two people and adjusting the linkage as mentioned in post #10 will fix it. You can't do it with one person...

LockDoc

[JointTech]

ok ill drag the wife out there tomorrow after we take her mom to lunch.

thanks for sticking with me guys!!

[SS Tim]

Think I have at least some of this figured out.
Couple of things to start.

It is called a shift tube because it is inside the column jacket and coaxial to the steering shaft. The fact there is a tab off the end does not make it less of a tube.

The entire adjustment is based on the detents in the transmission not the column.

So you do the basic gap setting first of the shift tube then adjust the manual linkage.

When you get to step 4 on page 7-27 the transmission must be in Neutral.

Nothing else is a reference.

The manual valve lever moved by the linkage rotates counterclockwise looking at the transmission from the drivers side.

Or the top rotates forward if that helps.

The positions are Park (fully clockwise), then one notch counterclockwise to Reverse, then one more to Neutral.

So that is the second bump from park (again fully clockwise). You might need to disconnect the linkage to get this correct then adjust the linkage to fit with the manual valve in the neutral position. I have notated a drawing to illustrate this and the positions are greatly exaggerated for clarity.

The adjustment of the indicator is not specified as such in the manual and my interpetation is that the shift tube is readjusted again after everything else is done and correct to align the dial/housing to the shift tube mounted needle. The inital gap is setting a baseline within design adjustment limits.

[SS Tim]

If it will help any here is a cutaway from the overhaul manual and I have notated the comb gear detent positions. The trans. is shown in neutral.

[JointTech]

hmm somewhere it got in my head the lever was called the tube... makes sense now.
tim thanks a lot for all the detail. great posts! im going to go out tomorrow with a clear head and try it again.

[JointTech]

ok im not getting much farther. After 4 hours adjusting and readjusting I have come to the conclusion im not very mechanically inclined. For some reason this shifter and my brakes are trying to get me. Engine, fuel, lights and electrical went much better. I like a challenge but its getting ridiculous.
but i digress...

For my piece of mind can somebody tell me if your detent is in position A or B when the truck is in park.
Figure A:




Figure B:



On my column, Fig. A makes my indicator go to here:


Figure B puts it here:



If B is correct like I think it is; what keeps the shift lever from going pass that point and falling off the lip? Just the fact that the transmission wont go any farther?

you can see I got a new universal shifter linkage from CPP. didnt help.

[JointTech]

fixed it. just kept at it and finally it all fell into place. the CPP linkage helped because the ole one was a welded together frankenstein and i didnt like the way it pivots off that nub on the frame. my brain cant work that many angles.
anyway it locks in park, wont go from R to P or N to R or from D to L2 without pulling back. and the indicator is lined up the whole time.

thanks for all the help guys.

[68shortfleet]

JT, how about a picture of where the linkage ended up at the base of the column like A and B in post #21?

I am dealing with the same issue, I just have not spent much time on it yet though.

[LockDoc]

-
Glad you got it sorted. In a thread like this it is important to mention every little detail. If you had mentioned that the linkage rod had been modified early on, my recommendations would have been different. I would have recommended that you replace it with a stock rod as a first priority.

LockDoc

[JointTech]

heres some pictures of the truck in P. It kind of a pain to get my phone in the there.










sorry some are blurry. my hands shake when im hungry...