1988 Monte Carlo 305 no forward gears

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Tyler

Not-quite-so-new-guy
Feb 7, 2015
14
4
3
hi I just got a 1988 Monte carlo ls 305 it has no forward gears can I fix it or sould I just swap a th350. I think it is a 200r4 but I could be wrong
 

thepcsurgeon

Master Mechanic
Oct 10, 2013
252
26
28
Orange County, NY
If it's an SS and If it's stock, it's a 200 4r. Good transmission but sounds like you may have snapped the main shaft, don't ask how I know this.......
If you use the TH350, you will loose the overdrive. The stock rear, 3.73, is a good match for the Monte SS. The 200 4r rebuilt will be expensive unless you do it yourself, not for the faint of heart.
 

Tyler

Not-quite-so-new-guy
Feb 7, 2015
14
4
3
It it a Monte carlo ls and it has reverse would a th350 bolt right up
 

thepcsurgeon

Master Mechanic
Oct 10, 2013
252
26
28
Orange County, NY
I think the th400 bolts up with the stock cross member. I think the 350 needs a different cross member, but I not 100% on that.
If you still,have reverse, you killed the clutches or one of the sun gears, either way, a rebuild is in order, no easy fix there. And still no overdrive. Good luck. Maybe some one else with expertise in the transmission department can sort out the internals for you.
 

truracer20

Master Mechanic
Feb 16, 2014
492
31
28
western PA
You need a different crossmember for the TH350. Otherwise it's an easy swap but if you have 3.73 gears the RPM's will be pretty high on the highway.
 

truracer20

Master Mechanic
Feb 16, 2014
492
31
28
western PA
The 200R4 uses the same exact drive shaft as the TH350 with the 6" tailshaft, The TH400 uses a different slip yolk and shaft length than either of the others. The 200R4 torque converter won't work with the TH350 or 400.

Also since your 200R4 has internal mechanical issues you should not reuse the torque converter even if you find a used replacement 200R4 transmission.
 
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