In my first car refurbish attemp im a little stuck.Im in the process of putting a 455 with a th400 in a 69 gs that had a 350 and the driveline that was in the car is too long.Is there a driveline made that I can use or do I need to get mine shortened?also the rubber bushing[dampner] is cracked.How far into the main shaft does the bushing go? thanks in advance Al
Stock '67-74 GM A-body Turbo400 driveshafts were 5/8 to 3/4" shorter than same chassis Turbo350 or SuperTurbine300 ('65-69 2spd) driveshafts. This measurement is with the exact T400 yoke that each GM division spec'ed for the car. Where many T400 conversions hit a snag is when installer picks the wrong T400 yoke & then uses the correct factory length driveshaft. One will then end up too long... IF using one of the "long" yokes with factory spec driveshaft. Over the years, have had a ton of driveshafts cutdown & "made" & have found there were at least 10 different T400 yokes used by GM in GM cars from '65-79. U-joint size, length, & whether splines go all the way to end, are the main differences in all these yokes. Have never liked having to do something twice, or using adaptor u-joints, so have always concentrated on using the correct yoke with correct length driveshaft. Original '67-72 BOP A-bodys with factory installed T400 used what I like to call the "medium" length T400 yoke. T400 yokes to be careful in using when using stock length T400 driveshafts, include: * the really looong T400 yokes used from the factory in: - '69-72 396-402 powered pickups, - '70 Chevelle SS's, - '70 1/2 TransAms, Formula's, & Camaro with factory T400 installation. - '71 TransAm & Formula with T400 & factory 3.42 gearing. All of the above used a shorter factory driveshaft to make up for the extra length of the looong T400 yoke. * the really short T400 yoke used in '75-79 Sevilles & '77 GrandPrixs. Would bet it was used in other late '70's applications as well... This is a very common Pick-N-Pull yoke. * another to avoid is the T400 yoke used in '66 Buick big cars. Have one of these I pulled years ago in a crusher yard, & the splines are different...will not work in the most popular T400 transmissions, only in '65(?)- 66 Buick T400's. Experience with 20-30 year old rubber insulated driveshafts has not been good. Most are dryrotted... if driveshaft has not twisted & destroyed itself:eek2: On these, we have found it best to remove the yoke, then pitch the rubber insulated shaft, then go back with a correct length "normal" driveshaft. Hope this helps gets you on the road. Later this Spring will have taken pics & will have dimensions of all the different T400 yokes & will post a link. :3gears: Roger
Help..again roger Hi roger, Wondering if you can tell me again if you remember if you have ever run across a 27 spline Pontiac rear differentaial. I have a cross pin type posi that has the springs stacked inside each other big spring with medium spring inside of it and even a smaller spring inside of it. I rebuild a GTO rear for a guy with one of these posis and disassembled it and cleaned the wholr thing. It had 433 gears ORIGINAL TO HIS CAR 66 Goat. The gears were too steep and he really wanted to just shelf the gears and save them for the future. I did not bother to count the splines. It is the same as that one was inside and out posi unit. So I guess only Pontiac used a 27 spline rear for a while or what? Sorry for hijacking the thread...Your just kind of tuff to get a hold of. lol Thanks for any info you can give. Jim
Jim, Hello, regret being hard to get a hold of. Putting in 75 hour weeks, unfortunately little time for boards, & on v8 my PM box seems to constantly get full :eek2: BOP 8.2's... Have had quite a few original 4.33 GTO rears over the years. All have had 4 pinion HD Safe-T-Track carriers with the "good" axles. Axles would be 28 spline, though, only pinion was 27 spline. Currently have 2 sets of nice 4.33's BOP gears, both from Goats. One set dated J65, another set dated in '67 or '68 o No: Can ck if have serious restorer needing a set. The HD 4 pinion Safe-T-Track 8.2 posi carriers am aquainted with are "clamshell" bolt-together design (8 long bolts hold the two sides together. If you can put up a pic or two of the posi carrier you have, I'll try & identify. Sure its not a 2 pinion unit, any large open windows? Or is it clamshell design, 4 pinion, with small windows? Thanks, Roger
Hi roger Glad to hear from you but not what I wanted to hear...lol. I will post pictures. The unit has a + cross pinion with a hollow center for the 3 springs to load the cones. The cones and side gears are separte from each other and there are 4 spider gears on each of the cross shafts all the same size. It has one window about 1" by 1" it also has the small right hand thread ring gear bolts with the large bop 3/4 head. They are NOT reverse thread bolts. Is it possible some one switched the side gears from another unit?? Auburn? Like I said the cone and the spider gear spline fit a 7.5 " pinion spline which is 27 perfect no slop and i cannot fit a 28 in and the 26 spline is very sloppy. o No: o No: o No: o No: o No: ou: ou: ou: ou: I will post pictures and even disassemble it again for you to see. Jim
