700r4 / 4 L60 into 55 Pontiac behind 389
 

After all the trouble with my 55 Star Chief and the dicussion on keeping the original Slant Pan Trans or the Sucsessor Turbo Hydra (oo ), coupled with the price of gas, I have lubhed into a non computer 4L60 trans. It is missing the tailhousing, Shift arm, Trans level housing &evel stick. A couple of minor things, the adapter goes between block & trans, TV cable, and need you'all to tell me what I don't know.

Anyone else put one in larely, Where new & used parts. Especiall a driveshaft yoke, Still cannot count that high for the splines. Kingman man

Have you thought about what you are going to do for motor mounts? When you remove the installed hydramatic, you remove attachment points for the rear motor mounts. Sounds like an ambitious undertaking, especially starting with missing parts.

... but he states "behind a 389" Larry. 389 blocks had side mounts. Getting that 4L60 into the '55 X frame will be a trick.

Had not thought about motor mounts specifically, my first thought was come here for advice. And Bill, the 4L60 IS about 6" longer, so really need advice, I have read where they are swapped into other cars. The 389 still has the front mount, If I continued to use the Strato Flight That has the rear mounts, but the price of gas!

If you plan to keep the front mount, you'd need to provide a set of side mounts about at the bellhousing to hold the engine in place (as Larry said). I don't know if you could hang the 4L60 on the back with no support like the HM did or if you'd need another mount there (very tight that close to the X of the frame).

And think about how much gas you could buy with the money you are going to spend of the tranny upgrade.

Yes Bill, the 389 has side mounts but the 55 frame does not. The frame would have to have adaptor pieces welded into each side of the frame for the side mounts. Plus a cross member under the engine should be added to prevent twisting of the frame at those mounts. Then you will need an additional crossmember at the rear transmission mount.

Then there is linkage to deal with, don't know what's involved with that but probably doable without too much headache.

I don't know if the 6" extra length will cause the trans' tail shaft to extend back into the car's X member. If it does then you probably want to scrap this idea.

I hear ya about gas prices. Weigh the cost of gas savings against the cost of this mod. If you aren't driving it a lot, it will probably take years of savings to pay for the cost of the mod.

First step for you, in my opinion, is to find out how you would do the engine mounts. There is no easy solution to that.

I SUSPECT that the the 4L60 would hang off the back without another mount point. I read that the 4L16 weighs about 150 lb, which is quite a bit lighter than the Dual Range trans.

The 4L60 has a rearTrans mount, had not considered side mounts! Thank you for bringing to attention. This is a long term project, First is engine with original trans and mounts. Trans is Chevy so will tahe adapter as well as rebuilding,then linkage and othr small stuff to sweat oc, but doing that first. One thing as I can afford it.

And lots of thought and work. Like What HM did? Dan

Anybody here actually done this???? Know where to find parts & info?:welcome:

"like what HM did" is in reference to the original Dual-Range HydraMatic (HM). Original HM bellhousing is in 2 pieces. The forward piece attaches to the back of the engine block and has "motor" mounts on each side. Then another piece bolts onto the forward piece. The HydraMatic transmission bolted to the back of the second bellhousing piece.

Thank you, could not figure it out and so simple.

I have seen an article or 2 about doing thie, Had not planned to do it but will have to find the article, believe on "Safari" and probably on my disk.

If the goal is to save money on gas, I suspect it will take a very long time and many miles of driving to make your money back on this swap.

What Stuart said. Saving gas is the last reason to do this swap even if you're putting 20k miles a year on the car.

Bill,

As the only one I know to answer this, As the ifo on "Safari" is only about "in car: repairs and as I would not turn my slant pan over to jest anybody. do you know of a full service manual? Dan

I have an original 1957 GMC Truck X-5706 Hydra-Matic manual that pretty much covers theory, maintenance and overhaul. 1957 GMC V8 engines were slightly detuned Pontiac V8s. GMC continued to use the dual-range Hydra-Matic until 1962 (Rolls-Royce until 1966). Shift points and throttle linkage setup would be different, but otherwise it would be pretty much the same. There is a 3 month old listing on eBay for two of them here:

https://www.ebay.com/itm/32525008155...Bk9SR8yhm_PkYA