Shift Points Too High???
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I have driven a 1999 Blazer LT for some years with no problems. I recently purchased a 1998 Blazer LT that has an issue I'm thinking is transmission related, but it could be electronic or control related.

At highway speeds or on level ground there is no issue. But going up steep hills either at launch or at slow speeds (up to 25 - 30 mph), the engine makes too many rpms before it shifts. We live in the mountains of WV so this is annoying. Going up a steep hill the 1999 that will shift from 1st to 2nd and 2nd to 3rd at about 2000 - 2200 rpm. Going up the same hill the "new" 1998 will shift at about 2600 - 2800 rpm.

I trust my mechanic very much -- he's a former Chevy service manager and knows his stuff. He has gone over the whole car and made many repairs. But he is miles away on much flatter ground in Virginia so it is hard to show him the exact problem. He says the transmission looks good in terms of oil pressure and computer codes. He has replaced transmission oil and filter and updated the transmission software, but it has not made any significant difference.

This could be a safety issue because accelerating uphill onto a highway produces too many revs and not the speed you expect.

Any ideas what this could be? Is there any computer input item or sensor that could malfunction and cause shift points to be too high?

Thanks guys.

 

Do they have the same differential gear ratio?

 

Yes, both are 3.73.