I took my 1989 S10 Blazer in for a new transmission filter and to have the pan magnet cleaned. It had never been done since I've owned the car. Car has about 170,000 miles on it, bought it with 120,000. Anyway, went to pick up the car after garage had closed, got the car back and it would not shift out of first gear until over 35 mph, and when it did it would shift hard. All other gears were fine, but first gear was a continual problem as I drove back home from mechanic. Anyway, long story short, I decided to try a product I bought from the local auto store that claimed it would stop hard shifting and slipping. I figured $10.00 was better than a new transmission. Tomy surprise, this product actually worked. I don't know the rules for posting recommendations for products here, but if anyone asks, I'll let you know. Really, I was surprised it worked.

Question: why would a normal running transmission suddenly develop this problem after only having the filter changed, the magnet cleaned, and some new fluid added?

Thanks.

 

Recommend away! I'm betting it was something to the tune of Lucas Trans Fix...

But anyway, sometimes when a transmission gets serviced after a long lack of service the result can be problematic. The phenomenon is called 'transmission shock' and it is when the new fluid mixes with the old fluid, sometimes causing foaming. Most of the currently available transmission fluids have anti-shock / anti-foam addatives to them, but it still can occur. The addative you used probably pushed the balance back to where it was supposed to be.

 

Thanks for the information. Yes, the product was Lucas.