Re: ultramatic issues

Posted by Randy Berger On 2009/6/26 22:03:27

If the fluid is very thin due to heat then the rear pump will not be able to create enough pressure to cause the upshift into Direct. When my friend first rebuilt my tranny in 92 he didn't notice the back neck of the rear pump had two grooves worn into it. He checked the pump rotor and it was within tolerance, so he installed it. It would shift fine for the first 10 minutes or so and as soon as the fluid warmed up and thinned out, it would not upshift because the rear pump could not maintain proper pressure. We tore the tranny apart and discovered the bad rear pump. We installed another pump and it has worked fine since then. I've never had it over 105.