Turbo 400
I am frame-off restoring my '70 LS5, automatic. I have tranny on bench and removed the pan last night. Very slight amount of sludge on very bottom of pan. No chunks and no burnt smell. Low mileage on car, so I am planning on doing only a fluid, filter, and front / rear seal change. And freshening up the aluminum housing with aluminum cleaner (unless anyone has other suggestions for getting factory like finish). I have the 1970 Chevrolet Chassis Overhaul Manual. It says to check end play of front turbine shaft on pg 7-247 of manual. It should be between .003" and .024". Mine is at .032". Apparently it can be adjusted with selective washers (colored and with various thicknesses) between the pump cover and the forward clutch housing. Has anyone run accross this before? Do you know where I can get these washers (and new gasket) and do you believe this is an indication of a more serious problem / should I reconsider a complete rebuild of tranny? thanks, Steve
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Re: Turbo 400
Steve------
I'll post the part numbers for the still-available-from-GM washers here in case they're of use to others. Each carries a GM list price of about 30 bucks.
GM #8625401-----.074-.078"
GM #8625402-----.082-.086"
GM #8625403-----.090-.094"
GM #8625404-----.098-.102"
GM #8625405-----.110--.112"
GM #8625406-----.118-.122"
The pan gasket is GM #8655625. However, it's also included with the filter kit. I would suggest replacing the filter if it's been in there a long time.In Appreciation of John Hinckley -
Re: Turbo 400
Steve you have a low mileage turbo 400. My original owner 70 turbo 400 has over 160,000 miles on it. I have only replaced the seals/fliter/fluid in just over 40 years, that is a long time and it performs great. I do not believe a low mileage turbo 400 would require a complete rebuild. My turbo did not get new seals until after it had 100,000 miles on it. I did replace the shift selector seal as well as the front and rear seals. I always have changed the fluid and filter as regular maintenance.Comment
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Re: Turbo 400
Steve,
The selective-fit thrust washers between the front pump cover and the forward clutch housing are part #'s 8623300, 8623301, 8623302, 8623303, 8623304, 8623305, and 8623306. They cover a range from .060" to .130" and are color-keyed to indicate their thickness. All are discontinued from GM but you should be able to find the one you need as leftover inventory at various dealers around the country.
LarryComment
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Re: Turbo 400
Larry and Steve-----
Yes, these are the shims required for Steve's situation and not the shims I previously listed. These are all GM-discontinued but in addition to GM dealer stock, I would think that a good automatic transmission shop should be able to supply these.In Appreciation of John HinckleyComment
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Re: Turbo 400
Great - thanks for the info. Any thoughts as to whether or not the larger than specified end play is an indication of a problem inside the tranny? Also - any thoughts on how to clean up the cast aluminum body? I tried aluminum wheel cleaner, but it didn't take off the oxidation. I am looking to clean it up without making it look 'non-factory'. SteveComment
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