Don't know Stacey... I met a few people years ago when it was on the road.. Met Carl in Carlisle Pennsylvania , yourself around the same time, I know there's a guy with a red rag top around Long Island somewhere, I can't remember his name... I know Paul in Connecticut that sells all the Buick parts, and Bruno of course....But hopefully in a couple of months this thing is finally on the road and then I can meet everybody again...
I don't know Stacy... I met Carl from the GS Club in Carlisle Pennsylvania a long time ago.. I know Paul who sells the Buick parts in Connecticut... And Bruno of course. But hopefully it's on the road soon and I can meet everybody again.
Larry the "Wizard" is so thorough....I'll bet he could have brought back Apollo 13 from the moon single handedly! Eric / Oregon
I have '71 TH400 that I pulled from an Electra in my 70 Skylark. Had it rebuilt in the mid eighties and converted to a short tail. I have an assortment of Driven gears , hoping I have the correct one for my application as I have replaced the original 12 bolt 2.56 rear with a '71 8,5 with 3.42 gears. I'm going to pull the housing and verify what Drive gear is in it, as it has been rebuilt, althou I would think that the guy probably just installed the Electra one back into it. Chart indicates that it should be an 18 tooth Drive gear if original. When I use the TCI calculator, input my tire size 26.5, differential gear 3.42, and drive gear tooth number 18, it spits out Not Available Now for an answer. Not sure where to go from here.... I'm sure that there are plenty of builds that utilized TH400s out of Electras that upgraded to 3.42 gears and run a stock 26" tire. What color Driven gear are they using? Thanks for any replies in advance, Jim/Rott
I'm curious if the OPs speedometer was accurate with the yellow 18 tooth Drive gear coupled with the brown 39 tooth Driven gear with the 3.42 geared differential? If so, I'm thinking Brown may be the ticket. ...Jim/Rott
You have 2 choices, change the DRIVE gear, or run one of those reducers. The DRIVE gear is a press on and off in most cases. You need a 16 or 17 tooth.
With an 18 tooth DRIVE gear, you would need a 47 tooth DRIVEN gear, which does not exist. With a 17 tooth gear, a 44 DRIVEN gear will work. A 16/42 will work as well.
Thanks for the reply, Larry. So I am assuming from your post that OPs original combo was inaccurate ? Someone probably just installed the highest numerical Driven gear that would fit in that housing (39) .Changing the Drive gear doesn't look like something I wanna try with trans in car. I'll have to look into the reducer box . Jim
I just use a calculator. 20168/tire height. Take the result and multiply by gear ratio and by DRIVE gear tooth count. Then divide the result of that by 1001. 20168/26.5 =761 761 X 3.42 X 16 =41642 41642/1001 =41.6 42 tooth DRIVEN gear.
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I've done some reading and I'm pretty sure I can change the Drive gear in the car. Pulling it seems to be tbe most difficult. Internet says use a long puller or cob something up, then heat new one a lil and slide in using a pipe. I will go that route when I tackle it. It looks like I need a Drive gear and a higher numerical housing for Driven gear. I may have tbe correct Driven gear, just have to look. Thanks for all your help Larry. Jim
Yup, maybe a local transmission place can help. The extension housing comes off easy enough. Might as well replace the bushing in the housing while you are in there. You might be able to replace the press on gear with a plastic one that is retained by a clip. Not sure.
As long as the Drive gear is plastic, apparently the metal Drive gear is a real PITA to pull. Won't know til I get in there. Should be able to tell if Drive gear is metal or plastic if I pull Driven gear housing and look inside. If it is indeed a metal Drive gear, I may leave it be and use a custom made adapter/reducer. Jim
Yes, easily, the opening is 2". Just look inside, you'll be able to tell. The 1971 BC and BT have the 18 tooth gears, BA BB, and OW, 16 teeth.
