Hello all,

I had my transmission rebuilt (allegedly) about eighteen months ago.

It has started to feel a bit sluggish at gear change and also in second gear I get a short rev just before or after the change, sometimes the revs fluctuate, normally when cold. Could this be a mechanical or electrical fault. The gearbox oil seems fine and I've had a look but could not see anything loose on the box itself.

Does anybody have a manual or link available that could help me out?

Does it always shift this way when cold? Does it shift better when its warm? Is it a diesel or petrol , or a V6? There could be several things causing the shifting , if the detent cable is not set correctly. The detent cable controls shift pressure via the throttle position . Also a restricted transmission filter will also cause this.

D teh shifting symptoms go away after the engine and trans warm up?

Yeah it seems to occur when the engine is cold at the moment, I can't say I have noticed any problems when warm. It is a petrol carby model. If there is anything I can check myself then please advise.

So it is carby and not injection, hmm our models here that year abandoned a carb in 1991. Nun the less if its car or injection. If the improper fluid was used , or the filter was not changed when the transmission was "rebuilt" will cause a fluid pressure issue when cold. The transmission fluid is thicker when cold , so if the wrung fluid is used or the filter is dirty , hasnt been changed when serviced , the fluid can have a hard time goin thru the filter when cold causing a slight pressure issue when shifting.

A dirty/old filter is restricting fluid pressure. When the fluid warms up its a little thinner so it flows thru the filter easier. If the wrung fluid is used this can also cause an issue. As different transmission fluids , like engine oil have different viscosities. Yu can service the fluid and filter and see if things get better.

Also , the transmission Detent Cable. Which is a cable that is connected to the transmission pressure servo in the transmission valve body via a cable attached to the engines throttle body. As the throttle is pressed and let go it varies the shifting pressure in the transmission. If it is not adjusted correctly it can cause cold shifting issues to a certain degree. Yu can check the detent cables firmness at the throttle body.