Transmission trouble in my 48 Chevy...

Hi!

I hope somebody here can help me, because I have got some problems with the transmission in my 48 Chevy. It is the stock three speed manual, and it works with my 261cui straight six engine. (Or at least it did work...)

I was driving the car to my parents place, and when I was like 100km from their place, I could hear this little noise, going "drrrrrrrr". I could'nt really figure out what it was at that point.
But when I was 70km from home, the transmission jumped out of the 3rd gear, and it had never done that before! When I was like 50km from home it started to jump out of the 3rd gear more and more often. The interval when it jumped out started to get shorter and shorter, and the last 10km it jumped out like every 100-300m. A bit annoying if I should say so...

I havent done anything to it yet, but Im going down south again this weekend to visit them (and my Chevy who is in their garage now), and will try to fix the problem.

If anyone in here might have an idea of what the problem is, it would really help me a lot.

Mikael

 

Step 1 check trans to bellhousing bolts.Sept 2 check all bolts relating trans, motor,bellhousing.

 

Thanks for your reply, I will definately go home and try that. Hope it will be that simple!!

 

...had a 50 Chev pickup that did the same thing, what happens is the shifter forks in the trans get worn on one side of the "u" shaped fork. All I did was pull the side cover off the trans,(no need to unhook the shift linkage) and pull the cover strate out, turn the "u" shaped shifter fork 180 degrees (it just swivels)and re-install cover. It worked as brand new after that.
I was given this tip from an oldtimer, it seems only one side of the shifter fork "u" get used all the time so it wears out; by turning it 180 degrees it's just like new.
This may or may not be your problem, but it's somethin easy to try. Good luck.

 

My vote would be the shifter forks too.

 

Does it still have the vacuum shift?

I've heard that the old vacuum shift Chevies,and especially 48s, had a real bad problem with jumping out of gear, especially on the highway. Don't know much about it, but that's what I hear. Anybody else know of it?

 

Yes, in fact I've seen old aftermarket kits at swap meets that consisted of a special shift arm and rod to eliminate the vacuum can.

 

Hmmm.... I actually dont know if it still has the vacuum shifter! But I will check that to!! I´m still running 6v on the car, and most of it is pretty much stock. My wipers are not running on vacuum anymore, but I havent changed that!

Sounds interesting with the u-fork, think theres is a great chance that it might be the problem!

Thanks for all your replies, It helps me alot!!!

Mikael