Having a piece of basic knowledge on how to service your 700R4 transmission is not a bad idea, so coming down here to read the step-by-step approach on how to get it done will be a worthwhile journey.
But before then, you must note that the 700R4 automatic transmission, also known as the “hydramatic,” was designed and launched by General Motor’s company in 1982 as a perfect substitute for TH350.
The 700R4 automatic transmission is a four-speed trans with powerful 30% overdrive situated at the fourth gear. This magnificent design was built to improve and economize fuel, among many other things.
That being said, doing an absolute auto transmission rebuild is an interesting option left only to the professionals, but adding one or two shifts or doing the overall trans service is something that anyone can tackle with the help of this guide.
How to Service Your GM 700R4 Transmission
The first thing to tackle in your sojourn to service your 700R4 transmission is the fluid. While it plays a key role in the auto trans, you can begin by replacing the filter. After all, that’s what the servicing is all about. So changing your 700R4 transmission filter regularly can extend the auto life cycle.
Without mincing words, below are the step-by-step approach on how to service your 700R4 transmission. This procedure is practically feasible for all seasoned General Motor (GM) automatic transmissions.
Step 1: Remove the Rearmost Bolts
The first thing you need to do in other to home-service your automatic transmission is to remove all the rearmost bolts. But before losing them, you should have a big drain pan waiting and ready.
That way, when the bolts are loosened toward the front rail, you will be able to control the pool of fluid that will flow out of the trans pan, and as such, you won’t make a big mess of yourself.
Step 2: Remove, Scrape and Clean the Gasket
After loosening the rearmost bolts with a stream of fluid flooding out of the trans pan, gently and completely place the pan on a clean earth surface so that the gasket can come off it with ease.
Sometimes, the gasket may come off in pieces, and at times, you may have to remove them manually. After which, you will scrape and clean the mounting surface. Take notice, it requires a thorough cleaning.
If it pleases you, you can use the solvents and carb washer to get the gasket pan cleaned up. And you can equally use a water-based degreaser (if you have it) in your garage sink.
Step 3: Remove the Transmission Filter
Having removed and cleaned the gasket, what is next in your 700R4 transmission services is to remove its filter. While attempting to remove it, what you see next is called valve body.
If you’ll be modifying and installing a shift kit, the valve body is what you are going to remove, but our main focus here is the filter and not the other way round!
So while you don’t have anything to do with the valve body, try to focus on how to safely remove the filter as this is exactly where many people do encounter problems when doing the transmission service themselves.
The problem there is that the seal that plugs the filter into its case often gets stiffed, harden, and stuck-up there. And if you attempt to shove another filter on top of it, it won’t seat, and it won’t fit into the pan.
So if you encountered a similar problem along the line, a plier with a pick and needle-nose will solve the problem.
Step 4: Trash the Drained Gasket Pan and Filter
If you are reading step 4, it means you’ve successfully removed the filter, and your gasket pan is fully drained. If yes, then keep reading but if the reverse is the case, repeat step 3 and check if your gasket pan is drained or still flowing.
At this point, the drained filter and gasket pan should be dropped into the dustbin, the fluid should be recycled, and the rearmost bolts should go into the sink.
Thereafter, everything should be cleaned up, and get ready to reinstall the transmission back, including the new filter and gasket.
Step 5: Install the New Filter
Remember that the old filter and gasket pan had to be trashed, so there is a need for new ones to be reinstated. Before you install the new filter, add a little fluid to its seal so that it can easily seats well in the case.
Having applied the fluid, gently push it into its place and after that, get the gasket pan ready. In doing that, wipe down the gasket pan mounting area with a lacquer thinner to ensure that it is free of debris.
Step 6: Install the New Gasket Pan
When you are sure that the gasket mounting area is free of any debris, apply a little adhesive to the pan, set it in place, and start tightening the bolts again.
In case you encounter any problem in so doing, try snugging the bolts down using another alternating pattern. But before then, make sure that the pan bolt you are using on the torque specs is not more or less than 80-inch-pounds.
Step 7: Top up the 700R4 Trans with Fluid
If you are reading this, it means you are almost done servicing your 700R4 automatic transmission for good. All that is left is for you is to add some fluid to replenish the lost ones in the cause of servicing it. Usually, auto 700R4 will take nothing less than six quarts of fluid after a service.
Step 7: Testing
Having added some fluid to your 700R4 transmission, your job is completed. However, you may have to run the vehicle to temperature, check your dipstick and carefully study its overall response to see if it is balanced or not.
But if you carefully follow the above steps, your vehicle will produce some sounds that are appealing to the ear.
There is no big deal on how to service auto 700R4 transmission, all that matters is to open the trans and change its filter and gasket pan. If you can keep repeating this process occasionally, your engine lifespan will increase.