3208 cat transmission options

[Tinker Fabrication]

I have an 89 GMC TopKick with a 3208 cat with a 5-speed transmission. Was modified from a box truck to a toter with a sleeper. When they cut the frame they took the two speed rear end out. Should I simply replace the two speed rear end or consider changing to something like a 13 speed. Needs a new clutch. So transmission has to come out anyway. I just don't know what's available that will bolt straight up? I tow primarily a flatbed for a skid steer and trackhoe. And 32 ft Plus campers Multistate toes. Five just isn't enough. Any suggestions would be appreciated. Thanks

 

[Coaldust]

Holy cow! She was made to haul and She tows it all!
Definitely needs a 13 speed.

 

[Delmer]

Five isn't enough how? do you need more down low? more overdrive? or more HP and RPM all the way through?

As far as I know, the five is a granny low and direct fifth. The two speed ratios were 4.88 and 6.something. I'd guess you have a lower numeric ratio than 4.88 now to get a little more speed on the highway, and you have to use granny more than you'd like? I don't think I'd want to go back to the two speed ratios, but I don't think I'd go for more trans either, how about a new engine while you're at it?

 

[Coaldust]

I’d drive that rig anywhere. No matter how many gears it has. One of these days, the judge will give me my license back.

 

[Birken Vogt]

I know it sounds like you probably like that truck, but from a dollars and cents perspective, its best days are behind it. I would scrounge a good working 2 speed axle from a junkyard somewhere, they can't be very hard to find these days. Then let the truck earn and save pennies for the inevitable replacement down the road sometime.

 

[Coaldust]

My goodness. We all know that. Don’t mention it out loud: Don’t shatter his hopes and dreams. Let Tinker maintain his youthful innocence, just a little longer. Even though, 1989 wants that 3208 back.

I graduated in 1989 from community college with the same hopes and aspirations. Let’s not spoil it.

 

[Tinker Fabrication]

Five isn't enough how? do you need more down low? more overdrive? or more HP and RPM all the way through?

As far as I know, the five is a granny low and direct fifth. The two speed ratios were 4.88 and 6.something. I'd guess you have a lower numeric ratio than 4.88 now to get a little more speed on the highway, and you have to use granny more than you'd like? I don't think I'd want to go back to the two speed ratios, but I don't think I'd go for more trans either, how about a new engine while you're at it?

Takes off fine. Good to about 60mph. Will do 72mph on the open road with governor holding her back. Just need a few in between to help keep speed up in the hills. 5th is to hi and 4th to low. Thats why it had a 2 speed rear from the factory.

 

[Tinker Fabrication]

Holy cow! She was made to haul and She tows it all!
Definitely needs a 13 speed.

Im old school. Love shifting gears and a good CB. Cant drive heavy anymore because of health. But me and "Big Red" have a lot if fun.

 

[Tinker Fabrication]

I know it sounds like you probably like that truck, but from a dollars and cents perspective, its best days are behind it. I would scrounge a good working 2 speed axle from a junkyard somewhere, they can't be very hard to find these days. Then let the truck earn and save pennies for the inevitable replacement down the road sometime.

Yup. Shes not an earner. Im retired. Just cant give the road up. Only has 215k miles on it. Turns a lot of heads lol. Ill be dead long before ol Red is.
Kind of what i was thinking. Just put her back factory. Im not smarter than the engineers that designed it. Have the original build sheet. So i know exactly what rear to look for. Maybe ill take advantage of rear being out and put air on the rear. Shes a little harsh on the rough stuff lol. Thanks.

 

[Tinker Fabrication]

My goodness. We all know that. Don’t mention it out loud: Don’t shatter his hopes and dreams. Let Tinker maintain his youthful innocence, just a little longer. Even though, 1989 wants that 3208 back.

I graduated in 1989 from community college with the same hopes and aspirations. Let’s not spoil it.

I know she ain't worth nothing. But ol girls got a lot of heart. Only has little over 200k on the clock. Turns a lot of heads too lol. Just a toy not an earner. Its actually my daily. Grocery store and all. Im retired. Just cant give up the road. Ill hook her to anything thats safe and mostly legal.

 

[Truck Shop]

What is the final ratio now? A RTO 6610 1st would be around 9.00 and OD of .80
RTO 6613 1st 14.00 and OD of .80.

 

[MG84]

How easy is it to come by a 2spd rear end with highway gears? I’m sure they are out there but I feel like most are geared pretty deep. I’ve got three medium duties and two are around 6.50/8.50 and the other is 6.65/8.85 I believe. Might be easier to find a transmission that’d suit your needs.

 

[terex herder]

Parts for the old two speed rears can be really hard to come by as well. Some of those old Spicers the driver and driven for 4th can be swapped for an overdrive, but doesn't sound like it could handle the jump from 3 to 5.

 

[crane operator]

I've had 3208's with small box 6613, and 9513 big box. Just have to find a small bellhousing, and I'd imagine those are getting scarce. Its probably not even going to be easy to find a 6613 anymore. I think mine were both push clutch.

Willie B did a bunch of work to a topkick like yours, his hood had all broken up under the headlights. I think his is 3208 also.

 

[Birken Vogt]

Shes not an earner. Im retired. Just cant give the road up.

OK, that is a different story. I thought you were earning money with it.

In that case I might look for a 13 speed also. Better to drive. Don't count out a 9 or 10 speed either. Anything that has twice the gears is going to be better than the 5. It will come down to whatever you can find for the right money.

 

[JaredV]

Put a brownie behind it.

 

[CM1995]

Welcome to the Forums TF! Glad to have you.

I think you'll fit in here just fine..

Ill hook her to anything thats safe and mostly legal.

 

[Coaldust]

He’ll fit in just fine.

Ol’e Tinker will haul your $hit. But, if you B$tch, he’ll unhitch.

I’ll be watching for Big Red out on the road. We’ll be able to smell that 3208 from a mile away, rolling coal with a flame out the stack.

 

[Tinker Fabrication]

I've had 3208's with small box 6613, and 9513 big box. Just have to find a small bellhousing, and I'd imagine those are getting scarce. Its probably not even going to be easy to find a 6613 anymore. I think mine were both push clutch.

Willie B did a bunch of work to a topkick like yours, his hood had all broken up under the headlights. I think his is 3208 also.

I've had 3208's with small box 6613, and 9513 big box. Just have to find a small bellhousing, and I'd imagine those are getting scarce. Its probably not even going to be easy to find a 6613 anymore. I think mine were both push clutch.

Willie B did a bunch of work to a topkick like yours, his hood had all broken up under the headlights. I think his is 3208 also.

Thanks for the info. I'll have a look see what I can find. Same problem with my hood. Just wasn't a lot of structure under the headlights for the hinge. Mine is on its second repair already. Changing hood and doors this year and respraying. I know it's stupid. I can easily buy a 2000s Peterbilt for what I've stuck in this old truck. I just got to have a soft spot for the old girl.

 

[Truck Shop]

There's more RTO6613's out there than one thinks. I wouldn't put a 9513 behind it, better
buy stock in ear plugs if you go the Howler Monkey route, 9513's were howlers even new.
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