корвет

In late 2007 my 1995 lost 3-4 at 153,000 miles.

I decided to rebuild it myself. Took me a year to do it, here and there. I got over 100K on the rebuild. The trans did have a small leak immediately after the rebuild. I never found where it was coming from, but suspect the front pump seal. I added a pint/quart about every 6 months or so.

Yesterday, at 260,000 the 3-4 went out again (I think). This time some grinding noises were heard upon take off, but disappeared about 30 miles later. I drove the car to work today in 2nd. Classic 3-4 burn out symptom, except the 107,000 mile ATF is dark cherry red with no apparent grit like I saw in 2007. Could it be something else?

Anyway, the fact that this amateur got 107K on my only Auto rebuild means I am going to do it again. I hope to complete it in under a month this time!

What I did in 2008: Lucked out and got AC Delco rebuild kit from eBay for $75! Included washers, frictions, steels, drum pistons and bands. Only 2 bushings, front pump and rear. Replaced all mentioned with homemade tools.

What I did not do: Change TC. I took my old one and drilled, drained, cleaned, tapped, sealed. I also did not change any bushings other than the two supplied.

I understand that worn bushings may be the culprit of my 3-4 failure due to wobbly/leaking shaft.

How hard, and what do you need to replace all the bushings? Do all the bushings need replacing, or are there some 'must do' bushings?

I noticed many kits today do not offer steels, bands or replacement pistons. Do all these components necessary need replacing?

My car is basically stock. The only aggressive driving I do these days are maybe a monthly spirited mountain run. Both failures occurred during mountain driving. I have a 1986 Z28 purchased new with a 700R4 that was parked with 336,000 miles and no 3-4 failure, never rebuilt. The Vette has 260K and 2 rebuilds.

Please provide your thoughts on my next rebuild.

Thanks!

tunedport85inject

i would replace all bushings if i was you,but it's a critical part of rebuild.you need lot of drivers to change the bushings.You could have the bushings replaced by a shop and complete a DIY rebuild .Lots of hard parts in a 260k miles trans need to be inspected for wear,front e rear planetary may be worn out now,sun gear front and rear too,you need to replace all accumulator pistons and ceck for wear into accumulators housing,if excessive wear you need to put a sleeve,the pump at 260k may show big wear where the rotors and vanes spin,some guys here change the pump and internals (rotor ,vanes,pump slide,spring,seal n' bushing.2-4 apply pistons,pin may need replacing,even the imput reverse drum ,where the band acts need to be cecked with a straight edge for wear...it's an old hi milleage unit...

confab

1) It should always get a pump bushing.. TS is usually bad also. The rear sun bushing should always be replaced. All others are test and replace.

2) You should replace the converter.. There's two clutches in there that you can't see or check. Even if both are fine? The vanes will collect garbage from the old transmission and deposit them into your new one.

3) It should always get a forward sprag, sun shell (The hardened ones are nice) and an EPC if it's an E unit. It should get always get rings and vanes. It really should have a TCC (the one in the pump) also.. (Because the quality is terrible on those)

4) Watch the recessed capsule in the servo housing. I replace those with a plug, but the capsule is replaceable as well. Pull it out with a tap.

5) EVERYTHING ELSE is check/test and replace.. INCLUDING CLUTCHES AND BAND, for a street driven car. ( I always do these anyway, but there's no technical reason to.)

6) Late E Units need to watch the TCC mod valve for wear..

confab

7) Do not discard the 3-4 clutch release springs.. As some transmission rebulders (Even some trade organizations) recommend.

confab

8) Disregard any spec for the 3-4 clutch. Set it at 45 to 55 thousand (You can go a little looser on a street car) hit it with compressed air, and check it again to verify the clearance.

Check the separator plate for wear, replace all checkballs with torlon plastic.