Gearcase compatibility - V4 Crossflow question

[ct1762@gmail.com]

Anyone know if its ok to use a 1991 and up lower on a 1989 v4 crossflow? Ive got a gt100 (1989) and a 1993 88spl with a good lower. The driveshafts are different, but I bolted up the 88 spl to the GT100 and it seemed to go toghether fine, but hope the newer gearcase isnt a tad bit longer as i can hear a slight wine at idle and the flywheel is harder to turn. Just curious if anyone knows. Im taking this one off and will swap to the 91' and older once I get to the shop. that slight whirring/whine has me worried. didn't go above a fast idle in neutral.

 

[havoc_squad]

Driveshaft splines are completely different. Have to change driveshaft on lower unit to match powerhead.

I would seriously pull that lower unit off and verify those splines very closely and not run it any longer until that is verified.

For lower units made 1992 and afterwards for V4 crossflows 1978 and up, the upper part of the driveshaft can be changed out more easily without having to re-shim the gearset with special tools.

I don't remember if you gain access by merely pulling the driveshaft seal cover or if you have to remove the propshaft bearing carrier and remove the lower driveshaft part to separate the two pieces.

 

[racerone]

The driveshaft spline count has been the same on V-4 and V-6 ( also those V-8 1986 to end ) motors from 1973 to year 2005 or so.-----But the length of that spline and seal arrangement on end of crankshaft changed.-----So if you back off all the bolts 2 turns does flywheel turn easier ????

 

[ct1762@gmail.com]

The driveshaft spline count has been the same on V-4 and V-6 ( also those V-8 1986 to end ) motors from 1973 to year 2005 or so.-----But the length of that spline and seal arrangement on end of crankshaft changed.-----So if you back off all the bolts 2 turns does flywheel turn easier ????

id bet dollars to donuts it will. correct case going on soon. I hope i didnt jam the splines up into the crank. that was not my smartest move.

 

[ct1762@gmail.com]

Driveshaft splines are completely different. Have to change driveshaft on lower unit to match powerhead.

I would seriously pull that lower unit off and verify those splines very closely and not run it any longer until that is verified.

For lower units made 1992 and afterwards for V4 crossflows 1978 and up, the upper part of the driveshaft can be changed out more easily without having to re-shim the gearset with special tools.

I don't remember if you gain access by merely pulling the driveshaft seal cover or if you have to remove the propshaft bearing carrier and remove the lower driveshaft part to separate the two pieces.

thanks great info much appreciated. The splines are 100% the same as Racer mentioned which is why i bolted it up, stupidly not measuring the driveshaft lenght. its a long story why that happened

 

[havoc_squad]

thanks great info much appreciated. The splines are 100% the same as Racer mentioned which is why i bolted it up, stupidly not measuring the driveshaft lenght. its a long story why that happened

I knew it wasn't the same specs to where it won't fit, just couldn't remember if it was splines, shape difference, length, or a mix of these.

 

[ct1762@gmail.com]

I knew it wasn't the same specs to where it won't fit, just couldn't remember if it was splines, shape difference, length, or a mix of these.

im sure bolting it up to torque was not bright. then again, ive done dumber things!

 

[racerone]

You put extreme load on on the lower ball bearing.-----And you forced the driveshaft down so that it could not move up.-----This results in the pinion and forward gear not meshing properly !!----Easy to correct all this.----Do not run the motor without making corrections.

 

[ct1762@gmail.com]

You put extreme load on on the lower ball bearing.-----And you forced the driveshaft down so that it could not move up.-----This results in the pinion and forward gear not meshing properly !!----Easy to correct all this.----Do not run the motor without making corrections.

right. done. new gearcase on. flywheel turns like a fluffy pillow. cheers racer.