debugging manual shift linkage
 

hi folks,

i know the shift rods had to be shortened as part of my 617 swap and i think they may be loose or otherwise out of whack. i'm looking for information on accessing and checking them. i've got a couple of illustrations of the system and i understand that with the cabin shift lever in neutral, the three levers on the transmission should be at rest.

i removed the assembly below the shift lever and it looked intact; presumably i need to work from underneath to see the linkages.

here are the specific symptoms i have experienced; anything in particular i should look for when the car's up on a hoist?

* a too-rapid shift from 1st into 2nd causes the lever to pull out half an inch, as if i were pulling it to enter reverse, resulting in grinding gears.

* i have twice gotten stuck in gear (lastly 2nd) and barely been able to get the mechanism moving again. luckily, i can mostly drive around town in 2nd, but obviously i want all four gears to work.

Did you change the fluid in the transmission?
Should be Type F ATF or one of the good transmission lubes like Redline MTL or the LubroMoly one. Old fluid can make shifting more difficult
Outside that, it sounds like you've got worn synchros.
I haven't done the Auto ->manual tranny swap myself but if you haven't changed the fluid in your new transmission, you can do that yourself with just a few tools and a few quarts. It's a cheap piece of maintenance that needs to be done anyway and it can't hurt trying.

Phil Forrest

Could be that your Shifter is worn and needs a rebuild kit.

How are the bushings on the ends of the shift Rods? sloppy or gone?

There is a hole in the each of the 3 levers hanging down from the shifter. It is right under the shifter, look for the 2 upside down "V`s" on either side. using a Drill Bit, nail etc... of the appropriate size keeps the levers lined up in natural.

Then adjust the length of the rods. make sure each of the Transmission levers is in the natural position.


Charlie

thank you phil and charlie. the transmission is original to the chassis (200K miles) - i do have a spare here if it goes south. i looked over the invoice for the swap and didn't see that the oil had been changed, so i can do that; it did say the linkage had got new bushings. i couldn't tell much from looking under the shifter so i assume i have to look from underneath next.


i still figure they may have got one of the rod angles wrong and the force sometimes goes the wrong way, so i mean to examine how they move together - if there's any slop in the system, busted bearings, etc.

adjust your shift rod length.
 

You could have them mixed up as well, Or they need to be bent so they don't bind together.
If the rod length is improper it will cause issues like you describe. If a rod is too long it wont come out of gear fully. If it is too short it wont go in fully. both issues will cause gear grinding. If the rods are not bent properly they will bind together when shifting. I bet if you readjust and re-bend the rods you will be in the clear. You can get under the car while someone else does the shifting and look at the linkage to see what is going on.

x2

to x2 charile- the shifter levers under the stick handle have a pass through hole that locks them all in place in slightly different positions. This is neutral. You can use an allen key close to the right size to lock them, when you do this all the levers on the transmission should be in the neutral position. if they arent, then they are misadjusted lengthwise.

Secondly binding issues can cause this problem to x2 C.doner, make sure you do as stated above, get someone in the driver seat to shift through while you watch. even a slight bend thats off will cause a binding and could prevent a full gear change.
Ive done this to myself a few times on projects where I had a bad bind and skipped over it to assuming major problems with the gearbox, the bend of the levers is really crucial to a clear shift

Well it is not hard to make it a mean thing to shift. There are a number of small things that can be wrong. You had to shorten them and if you shorten them all about 4 inch, that should be OK. Did you put new bushings in the eye of the adjustable ends, it is pretty cheap and easy to do. The shifter can be worn out. It is also rather inexpensive and not too difficult. But in doing all that, I still had trouble getting mine to shift nice and easy. So I made that little 6mm tool from a 6mm bolt. I cut the head and threaded part off the bolt and welded the threaded part at 90 degree to the smooth short piece of rod for a little handle. Then I ground the smooth piece at the other end to a point to make it easy to insert. Then make sure the transmission is in neutral and with that pin holding the shift levers in alignment, put the long shift rods in place and at the same time adjust there length at the clevis end to fit just right. Now here is a picture of the rods and there placement. If your transmssion is a late one they may differ - then let me know and I will fix you up with the correct one. This picture is of the shift rods through 81.

http://mb.ilcats.ru/part/class/1/ccode/F/cat/68K/type/123/subtype/123/group/26

They should all align evenly.

great advice everyone. just one question, in the exploded diagram, which parts are the "shifter"? the whole horizontal sliding apparatus?

#59, "shifting tube spring", i am wondering if it's too slack. it's easy to raise the lever half an inch and kind of rattle it around top-to-bottom.

i will stick a tool in the alignment slots and check that the three levers are all centered in neutral afterwards. great tip.

Items, 53, 80, 41, 11, 4, 92, 86, 93, 47, 38, 29, 56, 32, 26.
Slide them into #5 and that is the Shifter assembly.

Unscrew nut #68 and the shift lever should pull straight up and out. maybe # 62 Bushing is worn? Could be the spring is weak.

Take it apart and look at it.

Charlie