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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 77 cc lb on June 16, 2012, 03:37:16 pm

Title: trans shift
Post by: 77 cc lb on June 16, 2012, 03:37:16 pm

I recently bought an 88 R20 suburban with a 454/th400 trans. The trans. was rebuilt a couple years ago. It doesn't want to go past 2nd gear, was wondering if the modulator could be bad or something else. I added a qt of fluid because it was low and still no difference. Any ideas would be appreciated.

Title: Re: trans shift
Post by: slammed79 on June 16, 2012, 07:39:13 pm

Can you manually get it in to third? If not it could be gone.

Title: Re: trans shift
Post by: Lt.Del on June 16, 2012, 11:36:02 pm

you sure your vacuum line (to modulator) is still hooked up to the intake vacuum behind the TBI?  I guess the '88 TBI th400's are that way.
Passing gear stuck in passing mode?

Title: Re: trans shift
Post by: 77 cc lb on June 18, 2012, 04:03:30 pm

Thanks Lt.DeL and slammed I will check those out. I am going to try and get a hold of prev. owner to see who did the repair and a couple other things. Thanks guys