700R4 reliability questions...

[bnoon]

FYI... one fact I do know is that late '84 to early '85 was the switch over year for 27 vs. 30 spline, at least in F body cars. I've replaced the converter in my car and I have a spare '86 trans from a friend's '86 Trans Am parts car, both 30 spline. The thirdgen.org site and forums would confirm this info for argument's sake, but the site has been down since last week...

Thanks for the rest of the tips though. Some good info in there! The only thing I've heard about up to this point was the vette servo and a few line pressure mods... I will be doing the rebuild myself and it's my first 700R4/4l series rebuild, but I have been into auto transissions before TH350/400/C4/C6 etc, so at least I know the theory behind the bits involved.

I don't need the "brutal" tricks though. This car will be mostly a street car for cruise nights and such. Thanks!

[myclone]

I'll have to go back and check my info on when GM decided to start using the 30 spline input shaft but like I said Ive found 27 spline shafts in units up through late 87. The units could have been gone through before I got hold of them though so that may explain that in some or all the cases. FWIW/BTW, the GN/Turbo Buicks use the same small 27 spline input shaft on their 200R4 which has gone low tens fairly reliably so the small shaft isnt a huge issue as much as the early slush boxes not having a proper lube set up and/or pressure for hi po use as well as other fairly weak parts.

In general the later the unit the more updates or factory "fixes" will have already been done for you from the factory like one piece apply plates versus failure prone multi piece plates, lube mods for better reliability, etc. Try to get a vette unit or at least one out of a TPI car (IROC or GTA preferred) as it will already have stiffer servo springs and the big 2/4 servo which gives you nice crisp shifts but wont rattle your teeth at light throttle. One plus of the vette unit is that it will shift into OD at WOT where as some of the F body boxes will and some wont.

Pick up a "Beast" sun shell as the stock sun shell is a failure prone factory part and the beast part is cheaper than the updated GM 4L60E part if you shop around ebay.

If youre going to build the unit yourself then pick up an ATSG manual (ebay for ~$12) as well as a rebuild video of some type. Both those will help quite a bit if youre not familiar with building the unit.

If I can help just shoot me a PM or email as there are a few things you can do to help reliability that arent mentioned in the ATSG manual.

[bnoon]

Yeah, I've got a Vette servo setup ready to go since it's a rather popular thirdgen mod and I've also got a related line pressure modification/fix how to somewhere around here for better second gear holding power (quite a ratio change shifting to second). Where do I pick up a "Beast" sun shell though?

Searching for net for that and ATSG manual...

[bnoon]

Nevermind, found them both.

[bnoon]

By the way, would you know the part number for the new GM 5 gear planet?

[myclone]

Front planet: 24218063 ($127.40 last I time I bought one)
Rear planet: 24218069 ($257 last time)

[myclone]

Here are some more part #s you should check into for greater reliability.

8685044 One piece apply plate for the 3-4 stack (replaces failure prone 3 piece. $6)

8585043 A little heavier duty apply ring than whats normally found in a 700 ($14).

24200290 3-4 apply piston with molded rubber seal. Replaces piston that has seperate seal which can blow off under high press/hi po driving ($27).

24205272 Forward piston with molded rubber seal. Ditto on the reason for upgrade as above piston ($27)

24210961 High torque input sprag assembly package. Used on H2s and includes sprag, overrun clutch hub, retainer, inner/outer races, snap ring, and sun gear ($168).

24217328 Torrington roller bearing coversion for the reaction shaft to shell. Replaces a bronze thrust washer that can fail when driving "spiritedly" ($9)

8642191 Another torrington roller bearing replacement for thrust washer for the front planet and reaction carrier shaft ($4).

The "kit" for clutches, steels, seals, and gaskets for hi po use I like is from Transtar and is about $285.00 which includes blue plate clutches, Kolen steels, and a High Energy 2/4 band (wider 2/4 band). Part # K6100HP.

BTW, if you replace the trust washers with the torrington bearings then total thrust end play is CRITICAL. Too loose and you beat the torringtons to death and too tight you will end up with negative thrust clearance which will shatter the bearings and pieces of the bearings will ruine other expensive parts as well. With the bronze thrust washers they just get ground up into fine dust if the thrust clearance is less than optimum with no harm really done. I set my total thrust clearance at .005" but Im also VERY aware of fluid temps when racing so as not to over heat the alum pump and close up the thrust clearance. You can set your clearance to around .010" if you want and you should be ok if you dont run a trans fluid temp gauge. If you do install a temp gauge, which I highly recommend, plumb it into the "fluid out" line (the line carrying hot fluid to the cooler) as close to the trans as possible so you will get a more accurate reading of the internal temps of the trans. Plumbing a temp sending unit into the pan or anywhere else will only give you the temps of the fluid at that point not the heat its picking up where the stresses are highest in the gear train of the trans.

If you dont mind the cost use Red Line High Temp trans fluid but if the $100 a case cost of it is too much to swallow for a trans that sees limited track use then just use Dextron III with the biggest cooler you can fit in front of the radiator. The bigger cooler the better. Keep temps as low as possible and if you are racing and the temps get above 270deg let the trans cool some before going back out. At around 270 regular Dextron III is starting to break down and death to the trans cometh shortly. If you make a pass at the drag strip and the temps temporarily spike to 270 or slightly above but come back down quickly youre ok but spend any length of time running at or above that temp will kill the fluid (and the trans) after a while.

HTH

[bnoon]

Thanks man! http://www.gmpartsdirect.com has them for $121.46 and $245.52 shipped, so your prices are still pretty close!

I'm having trouble finding the 10 vane pump you mentioned though. Who did you get that part through?

Also, a question for this portion "Reverse input drum MUST be flat where the 2-4 band applies." I'm having trouble visualizing... Will this become more apparent when I'm looking at that portion of the rebuild? Is there anything you can do to expound on the description?

[myclone]

Where do I pick up a "Beast" sun shell though?

Searching for net for that and ATSG manual...

Ive seen the beast shell for sale on ebay by doing a search under "car and truck parts" then going to "transmissions" then typing in "700R4" and doing a search. You could prolly just do a search for "beast" in the trans section since there are usually several pages of 700 parts if you dont want to wade through all of the other pages. If memory serves me correct is seems that at times I would find several beast shells for sale while others there werent any so it may take scouring ebay for a few days to find one if there arent any listed on the day you look. There are usually several auctions for the ATSG manual though but be sure to get the one that covers the year trans youre working on since there are two different ATSG manuals available for the 700 (83-87 and 87-up).