tansmision issue

[bthrmbndts]

98 gmc blazer: shifts from first to sec. with no prob. at about 25mph it revs. high to about 3000 to 3500 rpms before shifting to third sometimes it doesn't even feel as if it shifts to third. just changed trans. filter and gasket, was told could be clutch.. please any advise would help?1

[MT-2500]

Originally Posted by bthrmbndts

98 gmc blazer: shifts from first to sec. with no prob. at about 25mph it revs. high to about 3000 to 3500 rpms before shifting to third sometimes it doesn't even feel as if it shifts to third. just changed trans. filter and gasket, was told could be clutch.. please any advise would help?1

If a standard transmission.
A weak clutch/pressure plate lets engine race up in higher gears.

Going down the road Put it in 4 or od and if engine races up you need a new clutch kit.

If a auto matic transmission get it on a engine/transmission capable scanner and see what is going on.
Any check engine lights on?
Make sure fluid level is good engine hot in park.
Make sure filter is the right one and on good.
Was there any metal or clutch in bottom of pan?
Does reverse slip or hold good?
If any codes post back codes.

[bthrmbndts]

automatic.fluuid is good hot in park, and reverse holds good, pan was clean , just dark fluid and filter black . picked up new filter from shop looks same , have friend that has dio. machine will hook it up next day or so.. what about idle air control or
?IAC

[MT-2500]

Originally Posted by bthrmbndts

automatic.fluuid is good hot in park, and reverse holds good, pan was clean , just dark fluid and filter black . picked up new filter from shop looks same , have friend that has dio. machine will hook it up next day or so.. what about idle air control or
?IAC

You need a transnmission capable scanner.

[bthrmbndts]

will get capabal scanner as soon as i can. Thank You for your help.

[MT-2500]

Originally Posted by bthrmbndts

will get capabal scanner as soon as i can. Thank You for your help.

You are welcome.
Read out all transmission slipage and shifting data.
Post back any codes.
Engine or transmission.

Was the transmission you took out doing the same thing or what was it doing?