Starter grinding, Th700 swap

[Chevy1981]

Here's my first post, so I figured I'd make it a good one!

First, I have a Goodwrench 350/TH350/NP208 in my 81 k10. I have had starter woes since the old 305 was buried with full honors. I have about 3/16-1/4" of shims on the outboard pad of the starter. I also ground off part of the material on the inboard pad, but it still grinds the flywheel. Checked clearance with a paper clip and a metal rod, it is way to much. The flywheel was replaced about 35K miles ago (along with a new TH350). It has a couple of chipped teeth, but is not in bad shape. My starter has the offeset bolt pattern, I've had at least 10 stock-replacement starters, and have replaced the starter pinion on 6 of them, no matter what, it still grinds the flywheel. I was thinking about trying an aftermarket high-torque starter to see if it would work better. Has anyone here had similar troubles? Are these high-torque models adjustable at all, with regard to proper clearance?

I can't afford to drive the old truck anymore 'cause of gas prices (gets about 6 lightpoles to a gallon), so I want to swap in a TH700, for the OD gear (plan to do this in July-August '06). Has anyone done this? What years did Chevy/GMC put Th700s in 4X4s with 208 t-cases? It should be a bolt-in deal since I have a Th350, right?

[NastyGMC]

83-87 on pickups is where you'll find the 700r4. Not necessarily a bolt in, the 700 is a little longer than the 350 so changing crossmember location and maybe driveshafts.
I'd take the milage with a grain of salt, maybe stay off the go-pedal a little bit more. and stick with the th350 for strength reasons.

[orangefj45]

so with the 35k on the setup, has the starter always had a grinding issue? if so, you'd have to do a process of elimination which would leave you with a possible bad flexplate.

[Brendanpotter]

Hey, I just did a complete 700r4 complete swap on my 1978 Chevy C10. Im no expert, but I can give you an quick idea of what I ran into...

Its a pretty easy deal, especially because the th350 and 700r4 share the same 27 spline output. If you get a newer 700r4 (preferable something 1987 or after) they work well because those were the years that the kinks were finally worked out.

NastyGMC is right, the 700r4 is about 3 inches longer than your TH350, which pushes back your crossmember location. Its not that big a deal, just a little drilling.

Your definetely will need a shorter rear driveshaft, and a longer front.

On mine, when I swapped the 700r4 did not use vaccum, so I need for the line coming out of the carb any longer.

The bolt pattern on the 700R4 is the same as the TH350, 6 bolts to the block. If your using a stock torque convertor, 3 bolts will hold that to the flywheel. I reused my old flywheel so I wouldnt have to change my starter out and it worked just fine.

You will need to swap out your TV cable (kickdown cable) as the TH350 and 700r4 cable are not the same. There are some good aftermarket cables you can get, however remember that there are about 30 different lengths of TV cable that GM used over the years if you deciede to rip one off of a donor vehicle.

Especially if your doing the swap to save on mileage and you dont wish to burn up your new tranny, make sure to get a Torque convertor lockup kit. TCI makes a cheap one, however I decieded to go with the B&M with in Cab control. Its a nice feature, and allows you to adjust lockup whenever you want.

Not a huge deal, but if you want to have full access manually of all your gears, you will need to change out your steering colum shifter. However, if you don't mind not being able to access your first gear manually, you can leave your stock colum in no problem. Your Drive becomes Overdrive, your second becomes your third gear, and your first becomes your second. ( Hope this makes some sense)

The Stock Tranny cooler lines connect right up, however if you were not running an extra cooler before, now is the time to look into this. The 700r4 makes alot more heat, and its not really a want but a need. B&M makes some pretty good coolers I dropped a 11"x11"x1 1/2 B&M and it does its job.

The OD is a nice feature, and I had never before driven around 50 miles an hour only doing about a grand. PM me if you have any other questions, I might be able to help, but hopefully this will give you a rough idea at what your looking at.

~Brendan

[PsychoticDeadGuy]

Hey, Brendan, glad to hear you got everything worked out. How is it running? D-Shaft work or did it need to be lengthened? I have almost everything I need to finish up my K5. It sure sounds like the 700 swap was easy.

Just make sure you get everything that you need. I got Brendan everything I had out of my K5, and it sounds like a pretty easy job.