I had asked about this earlier but never got a response. i have a 1987 s-15 jimmy that has a vibration in OD and occasionally in D too. when driving around town it doesnt do it but after about 30 highway miles and when i begin to drive around town again it starts. it does it when i push the throttle down and stops when i let off and once it starts it doesnt do it all the time. the fluid is clean and the filter has been changed. i currently have the tranny out and am going to change pump bushing and converter with my father so if someone could tell me what the cause of the vibration is and what i could look for in the tranny it'd be appreciated.
thanx,
micah

 

My first guess would be u-joints. A broken or sagging tranny mount can do weird things, too.

I suffered with a major rattling and shaking for over 2 years and 20k miles until a month ago. When I did the mods in my sig, I replaced the torque converter with a rebuilt/restalled/balanced unit from a local wholesale rebuilder. Smooth as glass now.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

Since you're doing seal and bushing on the input side, why not go ahead and do the output side, too. The output shaft bushing could cause problems too, like u-joints. The bushing in mine is worn out and it has a slight vibration to it and I can't keep it sealed. I'm just waiting to have the time and money to build my new one!

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Working on:
'84 Z28 LG4 305 with 209,000 original miles!
Dual electric fans (from a formula).
9 bolt posi disc rear with 3.27 gears.
145 MPH IROC Speedo
430 HP 350 (ZZ430) Coming soon! (Building it myself, so I don't get those AWESOME valve covers!)

Starting to look like the Kicker poster child!

ASE Certified Master Tech
+ L1 Advanced Engine Performance
+ X1 Undercar Specialist

And....A sig. that's getting way too long!