1990 JDM LJ78 1st gear slipping.

[markhc]

When the truck is cold from a complete stop or after I break hard to a stop, when I try to go again the engine revs up but the truck doesn't move (as if I'm in neutral).
I have to relax on the accelerator or the when the gear does kick in (after a second or two), the truck kicks forward too hard.
I've noticed these symptoms when the truck is cold. The truck is having no problems shifting in any other gears while driving. It's just the initial slip from a stop that I am experiencing.
It is an automatic transmission. Some people have suggested the shift solenoid may need to be replaced?

 

[kbushnz]

The first thing I would check is fluid level...
With it hot... and engine running and trans in N, check trans dip stick..
Should be in the "HOT" zone. I like to shoot for the top of the Hot zone.
Second I would check the cable which controls line pressure is set correctly.
If its still not right, get the trans flushed and renew fluid.
Then if its not working properly look at solenoids etc etc.
There is a great website Automotive Training and Resource Site
Goto Technical articles, and there is excellent write ups on how the Toyota transmissions work and testing procedures.

 

[markhc]

kbushnz...thank you for the link to the transmission articles. Which transmission is in the LJ78?

 

[kbushnz]

The LJ78 has a variant of the A340...They are all pretty much the same but change end letters like A340E A343F etc etc the difference mainly comes about which transfercase they are bolted to. And some have an extra solenoid to control line pressure where as ours uses a feedback cable attached to the throttle body.
But the trouble shooting is much the same...