Well, OB, oils age. We all know that. The same goes for automatic transmission fluid.

IIRC CB is from 1990, so that makes the fluid, if not changed yet, 27 years old. You wouldn't drive a car with engine oil of the same age, would you? You changed the oil (again IIRC)... The ATF has a change interval of around every 3-4 years (recommended by tranny experts). Purposely without any distance driven... Reason: 100.000 miles with say 20 cold starts is better for the tranny fluid than 100 cold starts in 25.000 miles. Every cooling to cold draws water (hygroscopic fluid, like brake fluid). Water causes rust. Rust causes wear. Wear causes tranny death... Tranny death causes OB to to fork out more money for a repair that could have been avoided by changing a fluid as recommended

 

Good Point Daim

May have to rethink and put it top of my to do list.

 

OB,

If that fluid has never been changed, then I'd suggest it's VERY overdue, irrespective of mileage. Here's a suggested approach that won't cost you too much:

Suck out old fluid with an extractor (I assume the GM box has a dipstick tube?). You'll only get about 2.5 litres out. Replenish with the same amount. Run for 10 miles. Suck out the fluid again. Drop the sump, change the filter, replace sump and fit new seal. Full with fluid. Run for 10 miles. Suck out fluid and refill. Total cost £40 of fluid plus filter and sump seal. Then do a suck and refill of 2.5 litres every year after. Cheap and quite effective maintenance regime.

Cheers

Paul

 

The TH400 has a dip stick. But you get a lot more out of the sump than 2.5l! As I removed mine to change the gasket and filter, I had something like 6l poor all over me...

 

Hi Paul@Daim

That sounds like a Plan!

Will the Colour of the Fluid tell me anything?

 

Yes it will.

Medium Red: all healthy
Dark Red: worn but still okay
Brown: badly worn
Black: really badly worn

Then the smell. It shouldn't smell burnt. If it smells burnt, then the oil is really damaging the tranny or better the tranny has been abused badly...

 

My fluid was red but the trans started slipping and when I pulled the trans pan there was quite a bit metal paste in the bottom.

So colour alone will not tell you the condition of the trans

 

I will try and get some fluid out, so I can see the Colour just to start with and then go from there.