A little help- Transmission Mechanics please...

[speednmark]

Ok so this is the second tiime ive had to send my baby off to the trranssmission shop in three weeks. This time i actually have no idea what caused the tranny to seize, but yees it froze on me. Its a 3 speed tranny. i think the munsie, anyways is it possible to take the core(guts) from a 3 or 4 speed transmission and install it using the same trannny casing that belongs to the origional 3 speed as of now(the three speed thats with thee truck right now- stock)?? if so what would i be looking at as of cost for the product, and does anyone have any suggestions as to where to go for such a thing- i live in austin texas, and by the way in case i get asked, its a 350 small block- stock....thanx - Mark taylor -

[Tx Firefighter]

You can't swap 4 speed internals into a 3 speed.

My money says it's the linkage locking up on you.

I've rebuilt a few 3 speeds and there is not much to go wrong with them. Most trouble stems from shift linkages causing two gears to engage at the same time, causing the trans to lock up.

[Brad]

Sounds like you should ditch that transmission. I have a Muncie that I just took out of my truck-it was the one that was rebuilt years ago and is running excellent. I would like to offer it to you, but I need to make sure my current Saginaw is going to function. If you can wait a week, I should be able to drive it and know for sure, if you're interested. We can talk price if you are interested.

[speednmark]

to: tx fire fighter, what do i do if this is the case.....do i go all out and replace the tranny all together or do i work piece by piece replacing, or do i crack her open, slide the gears back into place and hope it doesnt happen a K miles down the road???thanx for the help...also my speedometer gear is all messed up so it must be replaced, can i just replace the speedometer gear or do i need a whole new tail end of tranny to go with?

[Tx Firefighter]

You slide underneath the truck with a small mallet and tap the levers on the trans to where they are both in neutral.

Each little shift lever has three clicks. You want each one in the middle click. Sometimes, you have to jack up the back wheels to take the load off the trans.

This is a very common problem. The linkages get worn after time and allow the trans to engage two gears at the same time. Fix is to repair the linkage slop.

There are two speedo gears, the drive gear and the driven gear. The drive gear is very easy to change. All it takes is a 7/16 wrench and a minute or two.




The driven gear is harder to change, it's on the tailshaft. No need to change anything but the gear, but it is much more difficult to swap.



9 times out of 10, all you have to mess with is the driven gear, so it's no big deal.

[GMC AMI]

3 on the trees have a problem for the linkage to lock up in between gears
when there is wear and tear. If this is the case then mount a floor shifter
instead of using the 3 on the tree. I just so happen to have a nice one I almost sold to TX. One time on a very steep hill mine did that. I had to get a 18 wheeler to pull the truck a little bit so I could unlock the linkage. It took the pressure off the rear wheels so I could put it back to neutral allignment.
A little scary being under a truck on a steep hill when putting in to neutral. LOL.

[VetteVet]

Great pictures TX and I just wanted to add that damage to the speedo gears is not that common so be sure to check the cable making sure it turns freely in the housing. Sometimes they bind and if they don't turn then it will strip the plastic gears. Check the driven gear unit as well. VV