I have a 2004 H2 Hummer with a new Road Ripper 3 gearbox put in 18 months ago. Over the last couple of days the Hummer has problems changing up into gear. If your in drive and drive off slow it will rev up and speed up but wont change up a gear untill you take your foot off the pedal. Also if you use the auto in manual and start in 1st then go into second the gearbox itself will not go into the next gear unless you take your foot off the pedal. Now if your going down the box it will quite happily change down. I have changed the mass flow air meter and it is still the same, oil is fine no loss of oil. Can anyone help

 

Welcome. Always READ before you post anything. They are more likely to be able to help now that I have moved this to the H2 Vehicle section instead of the New Member Area where the top stuck post says: https://www.hummerforums.com/forum/n...questions-116/

 

Have you scanned it to see if there are any codes stored? A bad TPS might cause those symptoms. But you really need to scan it first.

 

Hi Ive had it scanned and no codes came up, we took it for a drive and scanned it on the move but still no codes. If you accelerate it wont change gear untill you take your foot off the pedal. I had the gearbox from certifiedtransmission but still waiting for replies at the moment no one seems to no anything. Any information would be good. The Hummer is a 2004 auto

 

Have you called Certified? They have some sharp guys on tech support.

 

they have told us to get a machine that will plug straight into the gearbox to controll the gearbox and see if that works so wont no untill monday on that

 

Keep us updated and good luck.