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Standard Plus
[Standard Plu]
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| by Jeff Thomas |
Date Added: Wednesday 02 August, 2017 |
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Before I tell you about David's work, let me tell you the backstory: I had my TH200-4R rebuilt by another performance builder in December 2016. After installing it I found out the builder used many of my old parts, forgot to modify the governor, never disassembled and cleaned the valve body, and failed to block the 2-3 control as part of the dual feed setup. There was a nasty 2-3 bind, second gear starts, a vibration and leaking seals. After multiple calls to the vendor and several repairs, it was never right. The vendor also sent me another valve body, but it was an early non-performance OG valve body that was worse than my original CZ valve body. I found David on the Turbo Buick forum and called him for help. He always answers his phone and he spent many hours talking me through potential repairs. David had me use the original CZ valve body and clean it. In the process I found an old Transgo shiftkit spacer in the 1-2 shift valve lineup which he had me remove. That solved my second gear starts. I also had issues with the servo. I developed a lot of respect for David after so many calls, so I bought a servo from him and he walked me through the installation. That solved my 2-1 downshift clunk. He also helped me fix the separator plate to resolve the 2-3 bind as much as possible, but the other vendor's separator plate was not drilled correctly to support a good 2-3 shift at lower shift points. It was fine at WOT. In spite of all the above, the transmission still had noise and excessive clearances with only 1200 street miles on it.
David's Work: Based on the above, I decided to bite the bullet and have David do a full Standard Plus build. I am extremely happy with the outcome. David air checked the unit and then tore it down to fix all the issues. He found the following: a missing splash shield, blown seals on the direct, hot spots in the direct clutches, a reused and cracked stator thrust washer, excessive clearances in the clutch packs, an incorrectly machined 4th clutch/overrun drum housing which caused chatter marks and hot spots on the 4th clutches after only 1200 miles, a plugged 3-4 accumulator with the old piston jammed up in the bore, old transgo springs in the valve body which were causing issues with the shifts, a bad sprag, and a missing wave plate. The other builder did rebuild the OD planet and the rear planet and those were well done and in spec. Finally, David found that although the other vendor did install the billet shaft forward drum, it had excessive runout and had to be replaced. We compared the other vendor's billet shaft drum to David's version and David's showed no visible runout compared to the other. David also checked the direct drum and it had holes drilled in it and it had a curve to the surface which prevented the band from making 100% contact across the face. David replaced the drum with his, which had no holes, and it was flat across the face. He replaced all seals, gaskets, thrust washers, bearings, bushings, clutches and the band. He also tore the valve body down completely, washed the parts, reassembled and checked for smooth operation. Where the valves were sticky, he micro-polished them and rechecked. He made some spring changes, removing the transgo parts and replacing for the correct calibration. He also used a brand new GM "X" separator plate and made his modifications for the dual feed direct setup. He repaired the pump and then reassembled the unit doing air checks on everything and checking clearances on all the clutch packs and other sections where required. Watching David do this showed me how meticulous he is on every transmission he builds.
Outcome: I got the transmission home, reinstalled it in a 1970 Camaro and all I can say is this thing is fabulous. All the previous issues are resolved. The shifts are clean and firm, not harsh. There are no flares. The 2-3 shift has no binding! Shifting from D to R and back is a smooth transition...no clunk or bang. The 1-2 shift is nice and firm, but not harsh. The downshifts are cushioned, clean and firm. Engine braking has been restored and I get the correct detent downshifts now. The shift points rise with throttle position and remain clean at every level. I made a filter change after 500 miles and cut the filter open and there was no notable debris. I couldn't be happier. If you want someone to build a solid TH200-4R, David is the guy to go to. I would be happy to talk to anyone in person...just ask David for my phone number.
Jeff
Rating:  [5 of 5 Stars!] |
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