automatic to manual in 89 Suburban

[magneticanomaly]

I have 1989 Suburban 2500 350 eng 4WD with dead TH400 auto trans
(VIN 1GKGV26K6KF517392)

I want to put a manual trans in it, instead of fixing the auto.

I have a 1988 Chevy 2500 pickup with a 350 and 5-speed manual trans.
(VIN 2GCFK24K2J1141685)

Transfer case in the pickup has front shaft on left instead of right, but it is the same model ((NP 241C). The manual transmission is the same overall length as the dead auto. Starter and starter mount are the same. Bolt patterns from transmission to transfer cases seem the same.

Looks like it will fit IF

1. Flywheel from pickup will fit on Suburban's engine

2. manual trans bellhousing will bolt onto Suburban engine

3. output shaft splines,length,etc. on manual trans is same as on auto, and therefore will fit into transfer case.

Can anyone tell me if it will work, before I take everything apart?

If dreams come true and I should happen to find some day a 6.2 Diesel, will THAT then work with my new 5-speed transmission?

Thanks for any suggestions!

 

[Motor_Head_Jr.]

These years 350 small blocks have a one piece rear main seal and you're in luck because they are all the same casting therefore the flywheel should should transfer over, the bellhousing pattern is the same, ans as far as I know the New Process transfer cases are pretty much interchagable from anything, I have done thransmission swaps on older models like the muncie 4 speeds from turbo 350s and never found an issue. The biggest problem you are gonna have is the center hump on the floor board in the cab. Last one I changed i had to hunt around wrecking yards for a couple months to find one tall enough to fit the manual transmission under, then cut it out wider than it needed to be, cut out the old hump, weld in the new one then figure out exactly where the holes needed to be cut to fit the shifter. However if you're taking that other truck apart then you should already have this hump. Oh and also if I am not mistaken your crossmember and tranny mount will need to be swapped and your spedometer checked to make sure that the ratios are the same (Probably are both being 2500 and about the same year but good to double check before you get a ticket, and usually spedo gears are cheap and easy to come by if you can figure out how many teeth you need to make the ratio correct). It'll be labor intensive with wiring swaps and possibly some cutting on the cab but I would suggest it I have always preferred manual transmissions to automatics.

 

[magneticanomaly]

Thank you, Motorhead!

I should have no speedo problem since I am keeping my old transfer case.

I went to the Chevy dealer this morning and checked part numbers for the transfer case input gear between the NP 241C in my right-offset transfer case and the donor pickup's left-offset NP241C, and they are the same P/N, so the output shaft on new transmission should fit the old transfer case. The fellow there confirmed what you said that the flywheels will interchange.

Thanks for warning me about transmission hump problem, but as you say I have the whole donor truck to borrow a hump from.

Time to go out and start pulling them out.

Thanks!

 

[Motor_Head_Jr.]

Glad to hear it. Post an update when you get her done would like to hear how it turns out. Also don't forget to get a good pilot bushing and install it before you put the clutch on the flywheel or that transmission will buck like crazy and cause damage to your ceankshaft. and double check the cab underneath the dash to see if there is a pre-cut spot for the clutch pedal linkage to go through the floor board and if there is a spot on the frame to hold it in place, there should be the cabs were all generally made the same as well as the frames, it was cheaper for them to do it that way.

 

[johnboymize]

i am trying to find out what all is needed to be changed out from a automatic to a five speed in my 91 z71 im not good on these computers so any help would be awsome