looking into putting a turbo 400/np208 from a cucv in my k5 with a 5.7. do i need to make any changes to the 400 to make it work with the gas engine ?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
turbo 400
- Thread starter riflerk20
- Start date
Torque converter and governor both need to be changed.
wage92
1/2 ton status
i did this swap and i put a different torque converter on, but never changed the governor. Is a diesel governor different because of the lower redline?
Just different shift points. It will still run with the diesel parts, just not the way it is supposed to.
wage92
1/2 ton status
ah makes sense. i will have to further investigate mine once i start driving it more in the spring. The governor can be removed from outside the trans correct?
OP sorry for the hijack, it looks like you just need to make sure converter and governor are changed, and if the truck didnt originally have a th400 in it you will need to move the crossmember and possibly play with driveshaft length
OP sorry for the hijack, it looks like you just need to make sure converter and governor are changed, and if the truck didnt originally have a th400 in it you will need to move the crossmember and possibly play with driveshaft length
Greg Ducato would know better than I,but I would say you could keep the six bolt diesel converter--far as I know three out of the six bolts will bolt up to a gas engine's flex plate,and GM did use them behind some gas engines factory,the lower stall speed was desireable in the heavy duty applications..less slippage means cooler running and better mpg..
I remember parting out a 80's G30 van that had a TH400 with the six bolt torque converter behind a 292 straight six,all factory installed...was a school bus van..also GM had service bullitens back around that time saying to use the six bolt converters in trucks that had a "shudder on acceleration" problem...(dont know if it cured it,but that was their "fix" I guess)..
If you didn't change the govenor,it would want to upshift too early ,but it wouldn't hurt anything except your 0-60 mph time probably..its so easy to pop one in from another TH400 there is no reason not too though..
I remember parting out a 80's G30 van that had a TH400 with the six bolt torque converter behind a 292 straight six,all factory installed...was a school bus van..also GM had service bullitens back around that time saying to use the six bolt converters in trucks that had a "shudder on acceleration" problem...(dont know if it cured it,but that was their "fix" I guess)..
If you didn't change the govenor,it would want to upshift too early ,but it wouldn't hurt anything except your 0-60 mph time probably..its so easy to pop one in from another TH400 there is no reason not too though..
you'll need a vac line for the 400 also if you're currently a 700r. Putting the 700r in my M1009 there was no length difference in the mountings.
You could get away with using the stock 400 diesel converter using 3 lugs to mount as Robert suggested. The stall speed will be kind of low but it will be good for crawling around in low gear and will deliver lower rpm in high gear due to less converter slippage. The governor is located behind the square 4 bolt metal plate at the rear of the case. Take off the plate and the governor slides right out. Get a gas governor and new gasket and you will be good to go. You might want to get that kickdown switch off the throttle pedal of the CUCV so you will have kickdown function. Run 12 volts to the switch, then to the vertical spade on the case connector on the drivers side. Be sure you adjust it so it is fully depressed at wide open throttle. As was mentioned, you will need a vacuum line from the engine intake manifold to the modulator on the trans.
this is what i was looking for, thanks all
You might also check for governor recalibration kits. I know at least at one time they were available for some GM transmissions.
I would assume Greg would mention it though, if that were a viable option?
I would assume Greg would mention it though, if that were a viable option?
Yes, forgot about that, these are still available as far as I know, from B&M ,but you could probably buy two or three gas governors for the price of a kit. The kits are geared more toward the very high rpm end of the scale, for racers mostly wanting to dial in a much higher shift point than what is possible with stock style governor calibration.
