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Tranny question and other driveline issues

Green Monster

Green Monster

1/2 ton status
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Aug 10, 2013
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Location
Thousand Oaks, CA
Hey everyone, I just bought a 76 K5 and the PO blew the rearend and tranny right before I bought it. A tranny shop replaced the gears in the rearend and installed a used TH350. A couple of times, I've backed it out of the driveway and when I put it in drive, it won't go into gear until I give it a little gas. After that, it's fine. Good, firm shifts. Also, it won't kick down (passing gear) and I'm getting a slight clunk in the rearend when I take off from a stop. The transfer case (203) i think has a part time kit installed because it has locking hubs. there is also a driveline disconnect for towing. I put it into 4wd, and the only position the shifter will go into is all the way forward, which I think is 4L. Other than that, the shifter is loose, feels like neutral. Can't shift it to the rear. Any suggestions?
 
A lot of potential issues going on here. First thing to do is check all of the obvious things. Is the front driveshaft engaging? Enough fluid in the trans? Is the TC shifter linkage out of whack?, how about the U-joints, vacuum line/modulator for TH-350?, rear yoke?, etc. Any one of those could have been affected during the transmission install. Odds are you will find issues with some or all the above. If you don't, then the next step would be to look at internal issues.
 
Govenor could be apple cored, or the kickdown isn't adjusted for WOT. Does it do it when cold/hot? I just went through this, ended up being a bad pump, my th350 is being rebuilt right now.
 
Having to "help it" into Low/Reverse (same assembly) is a sign of low line pressure.
You are having to "manually" shift that clutch, by forcing more fluid into the pump.

Just an FYI, that line pressure issue is carrying over to almost every other shift.
Which will take a good bit out of the life of the tranny. :waytogo:

It's one of those dormant issues, that you never feel, but the soft parts in the trans. Do...

as per yer other issues.

1) Check tranny fluid, with vehicle warm/running.
2) Check T-case fluid. (Not sure if 203's are tranny fluid, or gear oil. :dunno:
3) Check SHIFT LINKAGE, AT T-CASE.
4) Now... Check the tranny's Gov Gear, by removing its cover, and sliding it out.
*The Gov Gear is partially responsible for kickdown, as well as upshifts.
*a slightly stripped gov gear will cause nuisance problems, but fully stripped, and you only get 1st.

5) You should have already checked this, but make sure yer kickdown assembly is where it should be.
 
The 203 takes 30 wt. non detergent motor oil. Hopefully your trans is just low on fluid cause slow going into gear with the fluid level fine and your due for a rebuild
 
blazinzuk said:
The 203 takes 30 wt. non detergent motor oil. Hopefully your trans is just low on fluid cause slow going into gear with the fluid level fine and your due for a rebuild
Click to expand...

Exactly what mine was doing going into gear when cold wouldn't go in at all when warm.
 
I checked the tranny fluid after warming it up for about 5 minutes, shifted it a few times. Fluid was low, think I need a pint. Would a pint low cause this? As for the kickdown, I don't know how to check that. Won't kick down warm or cold. As for the t-case, oil is full. I don't know enough about the linkage to attempt diagnosis. All I know is that with the shifter all the way forward, it's in 4wd. When I pull it back, it feels real sloppy and is in 2wd.

Thanks everyone for your help, I really appreciate it. Steep learning curve!
 
The 203 shifter SUCKS unless it is working good and then its awesome look around on here lots of info on fixing them and modding them
 
blazinzuk said:
The 203 shifter SUCKS unless it is working good and then its awesome look around on here lots of info on fixing them and modding them
Click to expand...


Yes, you can pull the detent spring out and shim it with a 5/16" nut ground down.

Search "203 detent mod"
 
Looks like I'm taking it to the tranny shop that did the work. A little off topic, but does anyone know if oil coolers came on 76 K5s? I have one and the lines are leaking like crazy. Should I replace the lines or ditch the cooler? If I keep it, what are the best lines to use? And if I ditch it, do I need to do anything other than removing it (will the filter just screw into where the adapter used to be)? Thanks for your help.
 
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