pentiuman

HELP! I removed my dead 350 engine from my 91 GTA, auto transmission (of course). Before I did, I jacked up the trans a little, and put some wood blocks (four 2x4's stacked and nailed together, and a square peice of T-11 wood siding) underneath the trans pan. I believe this was what the book advised. Old engine came out pretty easy after I removed the two motor mount throughput bolts. It's possible the transmission fell down a little as we pulled out the engine, but if so, not much. Before I was ready to put the new engine in, I thought I noticed that the transmission had moved / fell a little and/or to one side. But since my blocks were undisturbed, thought I was imagining things.

But today/tonight, I was trying to install the new engine, and couldn't. The transmission seemed too low and/or to one side, or too far forward! If we lowered the engine to the same height of the bellhousing on the transmission and then tried to move the engine backwards, the part of the motor mounts that stay attached to the engine would hit their lower halfs that are on the car frame. If we raised the engine high enough to get over them, the flywheel on the engine would be going down against the transmission, and/or the two studs on the engine that go into holes on the bellhousing, and then we couldn't lower the engine.

It got dark, but before we quit, I got under the car and tried to jack up the transmission more. That's when I noticed that the transmission mount was broke - the rubber part of it was split right in two. (This is the mount right behind the transmission pan that attaches the transmission to a crossmember. The trans mount has two bolts at the top that bolt to the transmission, rubber in the middle, and a stud on the bottom facing towards the ground with a nut). Of course, I'm going to buy a new transmission mount and then try to install the engine. again.

Perhaps replacing the trans mount, some rest, and a good look of the situation in daylight will solve the problem. But now I'm stressing over how high to jack up the transmission after installing the new mount, and whether I should fully tighten the nut on the new mount before installing the engine, or leave it loose until the engine is connected? I don't want to break my transmission. If I install and fully tighten the new trans mount, should I jack up the trans at the pan until just enough weight is lifted for the rest of the car to start to move, or what? Can I safely jack up the transmission so that the engine mates with the bellhousing and the two studs, and then lower the engine into the engine mounts? I do NOT have a transmission jack - just a regular hydraulic one.

Pat Hall

iTrader: (31)

Personally, I'd recommend leaving the new mount detached from the crossmember until you get the motor mated up to the bellhousing of the trans. Just make sure you have the trans supported good with the floor jack and a nice, wide piece of plywood under the pan. There's no sense in binding up the trans by having the tailshaft bolted down while you're trying to line things up. The next suggestion I have is a no-brainer. Make sure to replace that crummy, stock, rubber mount with an Energy Suspension polyurethane mount. The stock ones are notorious for breaking too easily. It's only about $21 for the poly mount versus about $8 for the stock one, and they're worth every extra penny. I've managed to break a couple of the stock ones with an anemic TBI 305 motor if that gives you any idea of how weak they are. Haven't had any problems since putting the poly one in.

pentiuman

Pat - Thanks for the tips! I have a condition where I get confused easily under stress, so I always need help on some things. -I would have bought the better trans mount, but I didn't read your post until I had already got back from the parts store w/ the cheap one. Oh well. At least I know that if it breaks, that a better one is available. I'm gonna install the new trans mount at the transmission, and as you suggest, consider leaving the nut off where the stud goes into the crossmember at the bottom. May have to change plans if the threads are getting messed up. But if they're not, having the trans mount in (bolted at the top) can help me center the trans (from going right or left).

EDIT: The new trans mount has a plastic protective cap over the threads, so I may be able to leave the bottom nut off for more transmission movement during the engine install.

One person suggested I take the motor mount brackets off the engine, drop the engine in, bolt the engine to the transmission, then raise the engine and trans together enough to re-attach the motor mount brackets to the engine, drop them back down, and put in the thoroughput bolts at each side. I already have (kept) the following parts off, for more room: starter, oil filter, oil pressure sensor, and the exhaust manifolds.

Got to go do some de-greasing and try to install the trans mount. I'll check this later and post the results. THANKS!

pentiuman

Got engine in w/out removing motor mounts. But now I'm worried (maybe needlessly) about whether it's straight, and the engine hoist is rented and due back in just 6 hours. So, I'm starting a new thread to try to get faster replies from members who may have seen or read this initial post and moved on. Thanks everyone!